Ok, imgur on the phone is giving me fits tonight so no photos. So far I'm following the Dark Pixel build referenced in the Let's Build Something thread.
Day 1: Mounted the motors to the arms. Stripped the ESCs, desoldered the motor wires from ESCs and lined them up to trim the motor wires. Soldered them all, clockwise and counterclockwise.
Installed the red standoffs on the PDB. I intended it to be above the arms.
Helpful tip: take a soda cup lid and invert it on the table. The little buttons for cola, diet, etc hold 2 drops of loctite and make a perfect little bowl to dip the screws in. Use a magnetic screwdriver and you can mount the motors with no mess.
The motor wires on my motors were insulated and did not want to solder well at all. That or I have crappy solder, it might not be flux core (came with my soldering station). Couldn't tin the wires very well, even after scraping the coating off them with an xacto.
Day 2: I thought about it while I was at work, and when I stayed working tonight I removed the standoffs from the PDB. It will be much cleaner with that board on the bottom and all the wires hidden.
Hooked up the receiver to each ESC to test rotation direction. Good thing, one of my motors had a wire crossed that didn't look crossed yesterday, so I ended up with one of my clockwise motors spinning counterclockwise. Double check the wires are flat all the way out of the motor to avoid this mistake. Since the wires were so short, when I switched a pair of wires I had to use one of the unused pads on the edge of the ESC instead of the original placement in the center. Since those 20A ESCs are overkill i hope it won't give me problems later.
Considered heat shrinking the ESCs to the arms after testing, but realized I want to remove the excess wire and the BEC power wires., and I'll need to do a test fit to get those lengths right.
@djslack The motor wires have a varnish insulator coating since they can be used as windings. So yeah, it's not your solder or soldering skills... :) My ESCs are between the plates that hold the four arms.
@djslack Sounds like it's really coming along! Back when I was doing this kind of stuff for a living we used to use acetone or denatured alcohol to wash a surface (or wire lead), then a dab of flux before soldering. Flux core solder is convenient, but it just won't do the same job as a good solvent and liquid flux.
@ruouttaurmind If I have the time I should post pictures of my quad. I got my pigtail yesterday so I'm pretty much done except setting up the flight controller. I'll wait for the pdb and put that one in instead.
@ruouttaurmind thanks for the tips, I'll make sure to have some before the next time I do motors. Everything else I usually do all right, but those leads were tricky.
Day 3: Desoldered the servo leads from the ESCs. The first time I used the bigger general tip on the soldering iron, and bridged two of the tiny resistors next to the signal lead. Used desoldering braid to clean that up and switched to the fine point tip. The helping hands and magnifier came in handy here.
I got my motor orientations and labeled each arm. Started preassembly to determine my signal wire lengths. Considering rotating the cc3d to expose the usb port, and also shortening the fc-rx harness to clean up the wiring.
@djslack Man, you are doing great. I'm falling WAY behind you and Gary. I haven't seen any updates from @DJMajickMan in a bit. I expect he's prolly ready to fly by now. I gotta get crackin'!
@ruouttaurmind I wish. Think I need more parts. I don't have a 5v out on my PDB so I've got to find another way to power the KK. Also awaiting standoff's to get my layout finalized, the wiring harness in order for any of this to work, and I'm sure some other surprises as they come up.
@DJMajickMan You can pull 5v from one of the ESC's. Since they're all running to the KK anyway, just leave the center power line connected on one of the 4 and bippity boppity boo, instant power.
@DJMajickMan Surely. I'll snap one when i get home. But in summary, the ESC servo lead has a black wire, red wire and white wire. Black is ground, white is signal, red is +5v. Usually the red wire is removed from the JST connector on all but one ESC, and that ESC is the one that will provide +5v to the flight controller or radio.
@ruouttaurmind okay I think I see what you're talking about but a picture is worth 1000 words or a few bucks not spent on a BEC or another PDB with 5v out. Sorry for the thread jacking :S
@DJMajickMan Removing extranious +5V wires from 3/4 of the ESC's may not be necessary, depending on your FC. In the case of the CC3D it's not necessary to remove the additional power wires. In the case of the KK... I have no idea. I have done it with my CC3D just to be safe and avoid potential problems. It only takes a second to pull that center pin from the JST, and either snip the red wire, or simply shrink tube over the exposed Dupont connector on the end of the red wire and leave it in place. If you're unsure how to remove the pin without damaging the connector, here's 39 seconds that will serve you well! Note that some Dupont pins are held in place by a little plastic tab on the plastic connector itself. In that case, just gently pry up on the plastic with a knife, Xacto, small screwdriver, and slide the pin out.
@ruouttaurmind@DJMacickMan our connectors have the plastic tab. Since I'm running the PDB I removed power and ground wires from all the ESC harnesses and desoldered them from the ESCs, running only the signal wire from the FC to each ESC. I trimmed these wires to a reasonable length and resoldered the shorter wire to the ESC.
Day 4: Attached arms and cc3d to base plate, measured signal wires, disassembled everything, trimmed wires and soldered to ESCs. Put heat sinks and thermal pads back on and secured ESCs to arms with heat shrink tubing.
Decided to go with the FC rotated 90 degrees so that the USB connector is exposed on the side and the transmitter port is at the rear next to where the transmitter will be.
Learned that my RGB LED plans may not be possible without having a PPM receiver for a single wire connection. My Tactic transmitter doesn't have any PPM receivers available. I'll probably just go with the included light bars and try Openpilot first, and see what I can find out about the LED situation later. Cleanflight docs aren't entirely clear on the subject.
Also, all the nylon screws included in my standoff kit were longer than the short standoffs I used for the FC. I took an all-female standoff that was the same length as the FC standoff and threaded screws through it, then trimmed the excess off the other end with an xacto knife. Voila, perfectly shortened screws, about 3mm shorter than they started out.
@djslack Good find at HF! Price is good if I can find it in my local store. If not... I HATE to wait another two or three weeks for China Post, but I will probalby order some bright colored tubing. I think I'd like that bright green and bright orange on front and back.
Day 5: last night, i fixed the arms to the pdb and soldered all the esc power leads down. The power leads are just about the same thickness as the arms, I hope they fit well. The battery pigtail from banggood is significantly thicker than the arms so I took some of the trimmings from the ESCs and extended the leads to fit in the small space. I'm hoping to not run spacers.
Put some heat shrink around the DuPont pins for power and ground that I removed from one of the ESCs and soldered to the big 5v pads to power the rx. I'll probably do the same to the signal wires and lose the big plastic plugs; I may even undo what I did here and use an actual servo connector to make the power connection easier, but only if I end up plugging and unplugging it several times. Even though it won't be as clean, I'll probably just loop the receiver harness because i don't have crimpers and pins to shorten it.
@djslack I guess it really doesn't matter, but I put the pdb above the arms and putting the CF piece at the bottom. If you land on a shopping cart or a car, you can short out the underside of the pdb unless you somehow insulate it.
@garyhgaryh I started it that way, then changed my mind as I wanted as much wiring hidden as possible. That, and since I'm skipping the rgb leds for now, running the pdb on bottom exposes the included light bars.
I also currently have the included landing gear on the arms, although they may come off. I've been thinking about spraying the bottom with plasti-dip when it's done, as well as investigating hydrophobic coating for the cc3d board as it's exposed and caseless in my build.
Days 6-8: sparse work here and there. I got all the ESC wires routed around the arms with the plates sandwiched together. I used two nylon screws per arm stuck up from the bottom as sort of alignment pins. I then used a pick tool to push and pull the wires from the various access holes until I could see that they all went around the arms and wouldn't be pinched.
I then screwed the final bolts and nuts through the other two holes in each arm, removed the nylon screws and replaced them with the supplied bolts and tightened everything down.
The wiring harness supplied with my cc3d didn't match that on Openpilot's documentation. There are two blue and two yellow wires, and the white wire with the power and ground wires doesn't go to pin 3, but instead to pin 4. I opted to follow the cc3d documentation and connect the signal wires to my receiver by pin location. I looped the wires in a loose knot to take up the slack, i hope this doesn't cause any induction issues. I tacked the rx down with double sided tape.
I also wired my voltage display up to the battery pads on the pdb, running the wires up next to the standoff to the top deck and fixing the display with double sided tape.
The pigtail for the battery is way too long. I'm going to remove it and solder a male connector directly to the extension leads, putting the power plug maybe a half inch outside the back of the lower deck. This should make the wire length just about right. The hxt60 connector on the pigtail is much easier to remove that that on the Phantom, which is a welcome change. It still feels secure, you just don't have to fight to break it loose. I hope the individual connectors I ordered work that well, as that's what I plan to use.
I'm going for as few exposed wires as possible. The camera will add a couple more, and possibly a few more than that depending on whether I go with the board camera and vtx or the ilook camera @ruouttaurmind is sending me. But so far it's fairly clean. I may break down and get the tools to repin that receiver harness and trim all those wires to length, but that'll be down the road.
BTW, PDB guys, I don't know if this was as non-obvious to you as it was to me, but I just realized today the tiny solder pads along the side of the fc are for the esc signals - they each terminate at another tiny pad at each corner. Since I turned my fc sideways they don't line up for me (and I'm actually running mine backward to have the 5v at the rear by the rx and 12v up front for camera). But if you're exposing the pdb up top, this can clean up your wiring.
It would have been nice if any of this kit came with even a one page quick documentation set. Figuring it out has been fun, but a quick sheet with the kit and one with the PDB would have made a lot of things very clear very quickly.
@djslack Wow! Throw some rotors on that sucker and send it up! :-) I had the same issue with the CC3D harness colors not matching the CC3D documentation. I followed the docs and ignored colors, matcing the pinout. Everything worked as designed when I installed it in my (previously) crashed QR X350 Pro a couple of weeks ago.
@djslack RE: the solder pads on each corner and the row of pads on the edge... I did a continuity test and found they each trace to the row of pads on the edge, but it didn't occur to me they were intended for ESC signal. Great find to figure that one out! I searched high and low for some kind of documentation for the PDB and have found nada. Thank you for the tip! I think I'll put some header pins on the ones along the edge and put them to use.
Day 9: fought with a bad mini usb cable for a while, tried gcs software on my tablet and laptop but they couldn't detect the fc. Finally tried a new cable and got gcs to work.
Went through the setup wizard and I have a problem. When setting idle speeds Motor 1 would not spin. I set it the same as the others to get me through setup, thinking I had a bad solder joint on its signal wire. It passed the test before I disassembled everything, but I wasn't paying attention to idle speeds or throttle position; just a quick up and down to verify they spun and in the right direction.
When I armed the quad and ran up the throttle, three motors spin. At about 55-60% throttle motor 1 kicks in, and doesn't spin as fast as the others. It doesn't sound bad, but it sure won't fly like this. Now the question is, do I have a motor problem or an ESC problem?
Problem solved. Redid the ESC calibration, all motors spin up harmoniously now. Somehow the esc calibration must have gone wrong in the configuration wizard.
A little work on the pigtail, some prop balancing, and a few touches here and there, and she should be ready to get in the air!
P.S. I was worried about not having a calibration harness to plug 4 ESCs in at once. Calibration is trivial with the GCS software. Enable live testing of the motors, set throttle to max across all channels, and plug in the battery, then set throttle to zero and calibration is done.
@garyhgaryh Thanks! I'm currently puzzling over wiring the camera and vtx, all that exposed wiring bothers me.
I'm going with the surveilzone cam and TS832 transmitter, the whole setup is 30g lighter than the ilook and I can mount the camera within the frame. Unfortunately the vtx doesn't fit between the frame standoffs. So far I'm thinking I can move my voltage meter and put it in the back on top, or I can mount it sideways under the upper frame.
Day 10: Haven't gotten to touch this project for a few days. Last night I balanced props and soldered in some wire from one of the removed esc leads to the 12v pads on the pdb. Planned on using the dupont connectors to connect to the pins in the JST harness for the iLook camera.
Installed the vibration dampers to the camera platform, and the platform to the frame.
I also removed the pigtail from the battery leads and soldered an XT60 connector just outside the rear of the frame on my wires that connected to the pigtail previously.
Day 11: My surveilzone order showed up after lunch today, so I weighed the board cam/vtx/wiring (50g) versus the iLook and wiring (80g). I'd been playing with mount ideas for the iLook since last night and hadn't come up with anything better than zip ties to the camera platform. For weight and a clean setup I decided to go with the original plan for the board camera and ts832 transmitter.
Trimmed the camera board down to the inner 32mm size. Drilled out the holes in camera board and cf mounting plate to fit the nylon screws I have, it took a 1/8" bit.
Thought for a bit about vtx placement. The ts832 is too wide to go in between the standoffs on the frame. I thought of moving the battery display from the top rear and mounting the vtx on the top rear. The way the antenna connector comes off the vtx that end has to be hanging off whatever it's mounted to. This position would end up with wires running from front to rear for both power and camera.
I opted to try mounting the vtx sideways, under the top frame with the antenna coming out the right side. This keeps all the wiring short, within the first set of standoffs. It also puts the antenna directly above the tip of the front right prop. I don't think the props flex nearly enough to hit the antenna, but we'll see. I could use a smaller antenna with a fixed 90 degree bend and not be over the prop.
Because I'm not sure how well this will work, I left the camera harness intact and the power wires long and did everything with zip ties. This prevents me from using the upper camera platform as I'm using the holes it mounts in for zip ties. If I keep this arrangement I'll work the mounting out better.
Tomorrow I'll work on battery mounting. Not sure if I want to use Velcro or straps. If I had straps on hand I'd use them to keep from putting Velcro on my packs. I might even try to make some Built NY straps.
I want to keep the upper platform so I can mount my Midland action cam from Meh to do recording on occasion. This will wind up being 50g heavier than if I just used the iLook, but it won't be on there all the time and it requires no wires. The Midland 720p cam with battery weighs the same as the iLook and wiring.
Day 12: One battery strap made, there's really only room for one with this battery (it rides more forward than shown in the pic to get the cg right) but a second is in progress. If you bought Built NY cases from Meh you might recognize the neoprene:
Quick tip: the sticky back Velcro is not meant to also be sewn. You end up with glue all over your needle and thread. But glue is no good on stretchy neoprene, the Velcro also needs to be at least tacked down for structural integrity.
I can't resist, booting up the gcs to quickly verify which pids i loaded and going out for a test hover.
So I'm trying to figure out what exactly happened here. Either power glitched or the front right prop did strike the antenna. There aren't any marks--anywhere. Either my get out of the throttle reflex is really good, or all the escs shut down for some reason (radio failsafe?)
The vtx to camera wire loop got snagged in the front left prop when the antenna pushed the vtx to the left when it hit the pavement. The wires were around the prop but unharmed, so i know the prop wasn't powered at the time.
The rx case (safely caged in the rear) was popped apart. At first I thought my double sided tape had failed. No damage noted, snapped it back together.
I hooked it back up inside in the light, armed it and spun it up, everything appears normal. Man, this thing is loud, and it really moved some air in my kitchen.
I need to investigate what the receiver does for failsafe and see how to control that.
So I secured the vtx and wire loops better and took her out for another spin. This time not trying to hold the phone and fly at the same time. I also flew over the grass instead of out by the light.
Hovered for maybe two minutes. Noted a bit of roll oscillation, pitch seemed good. Yaw had a little drift to it, very slow and it might have just been my thumb's fault.
Just about the time I started to get comfortable and consider taking it for a circuit, it did the same thing from about 2' high. Roll right, crash inverted. This time the front left motor stayed at idle, all others had stopped. I pulled the battery and called it a night, i have work in the morning.
@djslack Wow, it looked great before the incident. I have to say, as crashes go (and I'm a guy who's very experienced in that subject) it looked pretty clean.
In slow motion you can see that it completed it's inversion before hitting the ground. Watching frame by frame it looks like the port side just... stopped, and the starboard side continued to run causing an inversion. My Syma X-1 has flips built into the firmware and yours had exactly the characteristics of my Syma when I execute a port side flip. Well, except the Syma continues around of course.
No damage to speak of? Looked like it hit pretty square on the lid.
@ruouttaurmind No permanent damage at all. I can't even find a scuff from the concrete. I think it landed squarely on the vtx antenna (which folded/moved) and then the cushy neoprene battery strap.
I'll be researching it until I can get to play with it tomorrow after work. I'll hook up gcs and get it to display my radio inputs and try to simulate the failure to see if it's a radio glitch.
@garyhgaryh only full stick in rate mode or rattitude mode, that I'm aware of. I was flying in attitude mode so there shouldn't be any inversion or any sudden moves like that.
Day 13: Made up a safety rig with string threaded through the landing gear holes, tied to the posts of two of our patio chairs. It's not perfect but it keeps it from going anywhere. Tested live display of radio input but it's super laggy (updates maybe 3 times/sec) and wouldn't show a brief glitch unless I was lucky.
Armed and flew. No real problems until I gave it right yaw input, at which point it immediately fell off in what surely would have been a roll to the right. When I killed the throttle, #1 motor stayed up at idle.
Swapped #1 and #3 connections at fc, problem followed motor #1, indicating the esc. Recalibrated escs and tried again-had to set the idle level way lower on #1 than on the rest (1006 vs 1065). This is weird because before they were all 1023 across the board. Lowered sync rates from 490hz to 400hz then 330hz with recalibration each time. Behavior is the same, including the lower idle level for #1, so I'm thinking I possibly have a bad esc. Wondering if I should write the vendor and see if they'll ship a replacement. I'll have at least 2 weeks of testing time if I take that route.
When I give it right rudder it immediately falls off to the right. When I give it left rudder it gives #1 and #2 motors crazy throttle up. Not sure what that means but it doesn't seem right. Maybe something is off with yaw on the fc.
@djslack That is odd behavior. Did you do a manual ESC calibration or did you use the OpenPilot routine? I was getting inconsistent responses with OP GCS so I switched to manual calibration and had MUCH better luck.
@ruouttaurmind i used Openpilot's routine. I figured the throttle signal is being generated by the fc, the raw throttle from the rx is never making its way to the escs.
Do I need a 4 way board to do a manual calibration? I can't do it through the fc, but have to go directly to the rx, right?
@djslack I connected my ESC to the RX Throttle ouput. Powered on my TX and set it to full throttle, then powered up the radio. You'll hear the ESC pulse the motor a couple times, then go quiet. Now reduce TX throttle to minimum. ESC will pulse motors again, then go silent. You're done. Repeat for each of 4 ESC. EDIT:I wrote "powered up the radio". What I really mean is power up the ESC, which in turn powers the radio RX.
@ruouttaurmind Thanks. That's what I thought manual meant I'd have to do. Because of my tucked wiring I'll have to take it apart enough to remove the fc. That's going to be a project for another day.
Day 14: didn't have time for a teardown to get to ask the wires to calibrate escs manually, so i erased the board and set everything up from scratch just for grins.
Everything is the same. Three ESCs calibrated right on the money, #1 is off and neutral is far lower than the others. Flight behavior on my string rig is still the same, and the #1 motor stays running at idle when I shut down the throttle, or even when I disarm the fc. It looks like the #1 way overspeeds on control input which would make it always flip to the right.
I just wrote the seller on Ali express asking about the defective ESC to get that ball rolling. Will start the teardown next.
@djslack They will ask you to do a manual ESC calibration after you send the video. I went through all that with them on my bad motor. After four replies from them asking for something different every time... and video proof of the process... I finally had to get pissy and chastise them before they finally agreed to send a new motor.
Hopefully you won't have to go through all that. But since you've got to disassemble to replace the ESC anyway, might as well do a manual calibration while it's apart so you can tell them "yes, I did that"
@djslack You have to co!tact them through the Aliexpress messaging system. Login to Aliexpress then go to your account and select Messages. I tried sending email but never got a reply until I used the Aliexpress system.
By the way, I received my replacement motor today. It took me about 10 days and half a dozen emails to convince them my motor was bad, but once they finally shipped the new motor it arrived in 6 days.
@ruouttaurmind Thanks. Crap. I just replied to her email asking for the video.
I'm thinking i might try to speed it along by offering to buy an additional extra motor and esc and a couple of spare arms. I could use spares anyway and they may be more inclined to go ahead and send me replacements if I'm sending a little money and getting more stuff.
@djslack You may be right. They asked me to buy more stuff while they were considering replacement of my motor. I checked their store, but didn't really see anything I wanted at the time and just told them "Thanks, not at this time, just the motor". Their next message included the tracking number.
@djslack Thanks for the video. I hope the seller sends you a new motor and esc. I like your string setup. I'll try flying my zmr250 this weekend on our lawn. If it acts erratically, I'll suspend it on strings like you did (ingenious :) ).
@garyhgaryh Thanks. When researching I read that someone said they used strings and sawhorses to bench test their quad. So I can't take credit, but i hope it helps if you need it.
My thoughts with it were to have enough slack to see what it tries to do, but tight enough the props won't catch a string.
They wrote back yesterday and indeed asked me if I had calibrated the ESC manually. Stated that if I did that and it still didn't work, that they would send me a replacement ESC.
They also asked me if the motor mount screws were too long on the #2 motor - mine are not at all.
Here's the video I took of the individual motor testing. One thing I notice: even on the two "good" motors, there is a difference in speed at full throttle. I don't have a tachometer, but I have a snazzy ukulele tuner and it tells me that at full throttle #3 spins just below an F, and #4 spins just below a D. The #1 spins at about half the speed of a "good" motor, and #2 begins to stutter above half throttle - this would be the culprit behind my flips to the right. What I don't know is whether it's a bad motor or a bad ESC.
I noticed when going back through AliExpress after writing the seller a message that these kits are on sale now for a few dollars less - $82 in my case. It's cheap for what you get, but I think their quality control seems a bit lacking. We're 2 for 3 on this forum with issues out of the box in what should be a random sample. It might be better to spend a few more bucks to have a better chance at flying on the first try. I'm tempted, I filled a cart with another $50 worth of stuff (two spare ESCs, a spare pair of motors, and a spare frame because I didn't see just arms for sale) but I don't know if I'm just throwing good money after bad buying spares of the same stuff that is giving me problems now. I might do better to go buy a set of motors and ESCs elsewhere and redo them all. I might buy a spare frame anyway, though - it's on sale for less than $20.
@djslack I think your money might be better spent buying those same items from readytoflyquads.com or getfpv.com. May not be the same frame though so not sure how swappable it will be. But from what I've read the quality control is better.
Ready to Fly is where I'm ordering my replacement and spare ESCs. $10 for a good ESC vs. a set of 4 ESC's for $24 that from our collective experience may have some bad ones :(. Plus US based company so it will arrive quicker. I'll spend the $4 for quality over quantity.
@djslack If you decide to strip the ESC's and motors and start over, consider downgrading to the 12A ESC's. They're a bit smaller, lighter, and more than capable for these tiny little motors. 20A turned out to be massive overkill, and SO BIG. That's what she said.
@DJMajickMan, @djslack I've bought (too much) stuff from RTFQ, and while the quality is fine, it's not necessarily quick, even though he's US based. I don't know if he's overwhelmed, or if he's waiting for China, but I'm not impressed with the speed. Maybe I'm spoiled by Amazon...
@fultonmartin Everything I've ordered from US suppliers, or purchased locally turned out to be identical to the items I've purchased from China. And in many cases, only a few days quicker than China. Even my last order fulfilled by Amazon took just over 2 weeks to arrive (no Prime here).
@ruouttaurmind Yesterday the seller got back to me and asked if I'd played with switching everything around to determine which things are actually bad. I haven't had time to mess with it, but guess I'll be disassembling this evening and weekend.
Day whatever: I spent some time this weekend getting up close and personal with my ESCs.
First up was motor 2, because the problem was less weird. I cut open the heat shrink and immediately found a problem: the lead coming from the second set of FETs on the ESC wasn't soldered to the board anymore!
Remember the problems I had tinning the leads? I took@ruouttaurmind's suggestion and went and got some acetone to remove the coating on the wires. Apparently scraping with an xacto knife wasn't enough. That done, the wire tinned fine and soldered back into place. Tested the motor connected directly to the receiver with good results.
I was then faced with the problem of getting heat shrink back on the arm. I did this work without removing the arm, and if I had to remove the arm then I would have to desolder the power leads and remove the ESC signal wire. Instead, I saw that if I took the bell housing off the motor, the heat shrink should fit.
This isn't as hard as it sounds. Pop off the retaining clip from the bottom and the shaft will push right out. The first time I did it, disassembly and reassembly probably took 5 minutes. By the last time I did it I could remove and replace the bell housing in under a minute. It would be super easy if you weren't doing it through the little hole in the arm.
On to problem child #1. Disassembled the same as #2, don't notice anything immediately awry. The #1 motor is the one that had leads crossed, causing me to miswire it the first time around and subsequently use the traces on the ESC (using the traditional motor lead solder points instead of directly to the FETs as they came wired) for the lead that was cut too short. The first thing I did was extend that lead and go back to the original solder point, with no positive results.
Next I switched motor #3 with #1. The problem remained with ESC #1. I started comparing the ESCs under the magnifying glass and saw a solder bridge on #1 that was not on #3. It was on the backside of the very tiny resistor(?) near where the signal lead is soldered to the ESC - the opposite end of that component from where the wire is connected to the board was bridged to the larger component next to it. I removed the bridge with some desoldering braid and got success!
The #3 motor is the one that seemed to spin a hair slower than the others, and this stayed with the motor at the #1 position. It doesn't seem to affect flight, though.
I reassembled everything, wiped the FC and set up from scratch, again on a string rig. Tested to full throttle and with full control inputs and everything seemed to behave as intended, so I took it out for a flight!
Here's crappy video made by holding my phone behind the transmitter, resulting in loud throttle clicks.
@djslack Wow! Great detective work Chris! Good job locating and resolving those issues.
The flight video was AWESOME! These things just SOUND fast, innit? Yours looks like it's pretty stable. You've done some great work!
By the way, I get my acetone at the dollar store in the form of generic nail polish remover. The cheapest, no-frills stuff is nearly pure acetone. Ninety-nine cents for 6 ounces.
@ruouttaurmind Thanks! It is pretty stable. I was testing control inputs, got pretty heavy on the side to side as you saw. Didn't go forward as much because what you couldn't see in the video is my neighbor's car about 10 feet away. I did test flying around in the circle after I put the camera down, it seems solid and I can't wait to get some daytime flying in. Hopefully my eachine camera/vtx kit will arrive and I can clean up that vtx arrangement with the smaller unit.
I used the QAV250 presets in GCS. Once I get the hang of flying it I'm sure there will be room for tuning the PIDs to get it nice and snappy, but it's plenty responsive with those presets from the few minutes I have on it.
@djslack Hell ya! I was grinning from ear to ear watching you fly your drone. Congrats on fixing your issues. It seems your zmr 250 is so much more stable than mine. Either that or you have better flying skills than me. :) I'm really happy you got issues resolved.
Can you do me a favor and measure the resistance between all your motor mount screws to battery ground?
@djslack I used the "Chinese ZMR 250". It was one of the last ones in the profile list. Mines are def. not open circuit (the rest. between the mounting screws and battery ground) .. :(.
@garyhgaryh I have 1806s, which is why I went with those presets, it seemed the closest.
You probably have battery ground touching the frame somewhere-a thick solder joint to a pdb or something might be likely. It's probably not harmful, most vehicles operate that way on purpose.
@garyhgaryh From an electrical standpoint, it shouldn't hurt anything. "If it ain't broke, don't fix it" sounds like a good plan to me. May you never have a reason to tear it down and find the short.
Got my first real flight in today. Have to get an adapter to get the Quanum V2 goggles to plug into the VRX, so I flew with the screen for a minute. Video signal kept pulsing to white, not sure what that's about, so I just flew a pack LOS.
@ruouttaurmind It's stupid fast. Exactly how i wanted it. I'm embarrassed because I flew the rest of that pack with no loss of control. I think I didn't give it enough throttle when I flared back to slow down, and was worried about keeping the camera on it more than flying it.
It flies great! Super responsive. The slow motor does show itself in flight--if I punch the throttle for an all out climb, it veers off to the left about 10-15 degrees. But in normal flight it appears to compensate pretty well.
Stuck the Meh special Midland Action Cam on the clean plate today and took it out to fly a pack. I went to a big open field because I wanted to go fast, but flying line of sight this thing gets too small too quickly, I chickened out on going very far and upon reviewing the video I didn't use much of the field at all. Next mission: get the goggles working.
Pack was a 1500mAh Turnigy 3S. I kept coming back to check my voltage meter on the back of the quad. The last check I saw 10.6 so did one more fast pass out and back, and when I came back it said 9.97, so I set it down fast. I didn't want to go much below 10.5. But a solid 7 1/2 minutes of flying is not bad, it would still get over 5 minutes if I ran it hard the whole time.
@ruouttaurmind I don't think it's just the camera. There is a dizzying moment when I did 2 or 3 360's in a row just to see how fast it would spin with full control input, and it's fast. A couple of my fast passes back towards the road behind me, I did quick turns and stops and it's very maneuverable. This is on the base settings, I haven't played with any of the tuning or different modes in GCS yet (though I'm itching to put Rattitude on a flight mode and get some flips in).
More LEDs may help with visibility, flying higher wouldn't hurt either. But honestly my solution is just to go FPV. I want to see zooming along fence lines or under tree branches from the quad's perspective, anyway. I could cover a lot more ground with a good FPV link and not worry about losing my orientation.
I finally got my first fpv flight in yesterday evening just as the sun went down. I've got to say, that takes some getting used to. I think I flew for 2 or 3 minutes. I don't get motion sickness from games or anything, but I definitely felt disoriented and a little queasy from the goggle view. I then switched to a monitor for my friends that showed up to be able to watch.
Next plan is to go find a pretty deserted place. Learning FPV I think is going to require a large open area with (a) no places I'd have a problem retrieving a downed quad - like other people's fenced yards, and (b) a low likelihood of drawing spectators. This hasn't happened but I can totally see it at any of the little places in my neighborhood. Time to go to the country.
Yeah I just got up to PA for some vacation time and put together my 250 FPV. Will be posting a thread for that later. Major issue is the "Hoity-toity" people up here who get up in arms about everything are full on anti-drone with statements of we have to many small craft airports in the area etc. etc. One of those airports is not even an airport it's an abandon landing strip.
Ok, imgur on the phone is giving me fits tonight so no photos. So far I'm following the Dark Pixel build referenced in the Let's Build Something thread.
Day 1: Mounted the motors to the arms. Stripped the ESCs, desoldered the motor wires from ESCs and lined them up to trim the motor wires. Soldered them all, clockwise and counterclockwise.
Installed the red standoffs on the PDB. I intended it to be above the arms.
Helpful tip: take a soda cup lid and invert it on the table. The little buttons for cola, diet, etc hold 2 drops of loctite and make a perfect little bowl to dip the screws in. Use a magnetic screwdriver and you can mount the motors with no mess.
The motor wires on my motors were insulated and did not want to solder well at all. That or I have crappy solder, it might not be flux core (came with my soldering station). Couldn't tin the wires very well, even after scraping the coating off them with an xacto.
Day 2: I thought about it while I was at work, and when I stayed working tonight I removed the standoffs from the PDB. It will be much cleaner with that board on the bottom and all the wires hidden.
Hooked up the receiver to each ESC to test rotation direction. Good thing, one of my motors had a wire crossed that didn't look crossed yesterday, so I ended up with one of my clockwise motors spinning counterclockwise. Double check the wires are flat all the way out of the motor to avoid this mistake. Since the wires were so short, when I switched a pair of wires I had to use one of the unused pads on the edge of the ESC instead of the original placement in the center. Since those 20A ESCs are overkill i hope it won't give me problems later.
Considered heat shrinking the ESCs to the arms after testing, but realized I want to remove the excess wire and the BEC power wires., and I'll need to do a test fit to get those lengths right.
@djslack The motor wires have a varnish insulator coating since they can be used as windings. So yeah, it's not your solder or soldering skills... :) My ESCs are between the plates that hold the four arms.
@djslack Sounds like it's really coming along! Back when I was doing this kind of stuff for a living we used to use acetone or denatured alcohol to wash a surface (or wire lead), then a dab of flux before soldering. Flux core solder is convenient, but it just won't do the same job as a good solvent and liquid flux.
@ruouttaurmind If I have the time I should post pictures of my quad. I got my pigtail yesterday so I'm pretty much done except setting up the flight controller. I'll wait for the pdb and put that one in instead.
@ruouttaurmind thanks for the tips, I'll make sure to have some before the next time I do motors. Everything else I usually do all right, but those leads were tricky.
Day 3: Desoldered the servo leads from the ESCs. The first time I used the bigger general tip on the soldering iron, and bridged two of the tiny resistors next to the signal lead. Used desoldering braid to clean that up and switched to the fine point tip. The helping hands and magnifier came in handy here.
I got my motor orientations and labeled each arm. Started preassembly to determine my signal wire lengths. Considering rotating the cc3d to expose the usb port, and also shortening the fc-rx harness to clean up the wiring.
@djslack Man, you are doing great. I'm falling WAY behind you and Gary. I haven't seen any updates from @DJMajickMan in a bit. I expect he's prolly ready to fly by now. I gotta get crackin'!
@ruouttaurmind I wish. Think I need more parts. I don't have a 5v out on my PDB so I've got to find another way to power the KK. Also awaiting standoff's to get my layout finalized, the wiring harness in order for any of this to work, and I'm sure some other surprises as they come up.
@DJMajickMan You can pull 5v from one of the ESC's. Since they're all running to the KK anyway, just leave the center power line connected on one of the 4 and bippity boppity boo, instant power.
@ruouttaurmind seen any photo's of this so I can get a clear picture of this my head is full of useless IT stuff right now ;)
@DJMajickMan Surely. I'll snap one when i get home. But in summary, the ESC servo lead has a black wire, red wire and white wire. Black is ground, white is signal, red is +5v. Usually the red wire is removed from the JST connector on all but one ESC, and that ESC is the one that will provide +5v to the flight controller or radio.
@ruouttaurmind okay I think I see what you're talking about but a picture is worth 1000 words or a few bucks not spent on a BEC or another PDB with 5v out. Sorry for the thread jacking :S
@DJMajickMan So on one of the ESC's you connect the unmodified servo lead into your flight controller:
@DJMajickMan On the other 3 ESC's you just remove the red wire from the JST connector:
@DJMajickMan Removing extranious +5V wires from 3/4 of the ESC's may not be necessary, depending on your FC. In the case of the CC3D it's not necessary to remove the additional power wires. In the case of the KK... I have no idea. I have done it with my CC3D just to be safe and avoid potential problems. It only takes a second to pull that center pin from the JST, and either snip the red wire, or simply shrink tube over the exposed Dupont connector on the end of the red wire and leave it in place. If you're unsure how to remove the pin without damaging the connector, here's 39 seconds that will serve you well! Note that some Dupont pins are held in place by a little plastic tab on the plastic connector itself. In that case, just gently pry up on the plastic with a knife, Xacto, small screwdriver, and slide the pin out.
@ruouttaurmind @DJMacickMan our connectors have the plastic tab. Since I'm running the PDB I removed power and ground wires from all the ESC harnesses and desoldered them from the ESCs, running only the signal wire from the FC to each ESC. I trimmed these wires to a reasonable length and resoldered the shorter wire to the ESC.
Day 4: Attached arms and cc3d to base plate, measured signal wires, disassembled everything, trimmed wires and soldered to ESCs. Put heat sinks and thermal pads back on and secured ESCs to arms with heat shrink tubing.
Decided to go with the FC rotated 90 degrees so that the USB connector is exposed on the side and the transmitter port is at the rear next to where the transmitter will be.
Learned that my RGB LED plans may not be possible without having a PPM receiver for a single wire connection. My Tactic transmitter doesn't have any PPM receivers available. I'll probably just go with the included light bars and try Openpilot first, and see what I can find out about the LED situation later. Cleanflight docs aren't entirely clear on the subject.
Also, all the nylon screws included in my standoff kit were longer than the short standoffs I used for the FC. I took an all-female standoff that was the same length as the FC standoff and threaded screws through it, then trimmed the excess off the other end with an xacto knife. Voila, perfectly shortened screws, about 3mm shorter than they started out.
@djslack What size shrink tube did you use to secure the ESC to the arms?
@ruouttaurmind It says 1" dia, i guess that's post-shrink size. Harbor Freight has a set of 5 boxes, 4 feet of each size, for 5 or 6 dollars. I used the largest size from that set. http://m.harborfreight.com/5-piece-heat-shrink-wire-wrap-assortment-9639.html
@djslack Good find at HF! Price is good if I can find it in my local store. If not... I HATE to wait another two or three weeks for China Post, but I will probalby order some bright colored tubing. I think I'd like that bright green and bright orange on front and back.
@ruouttaurmind I do like that green and orange. Should stand out.
Day 5: last night, i fixed the arms to the pdb and soldered all the esc power leads down. The power leads are just about the same thickness as the arms, I hope they fit well. The battery pigtail from banggood is significantly thicker than the arms so I took some of the trimmings from the ESCs and extended the leads to fit in the small space. I'm hoping to not run spacers.
Put some heat shrink around the DuPont pins for power and ground that I removed from one of the ESCs and soldered to the big 5v pads to power the rx. I'll probably do the same to the signal wires and lose the big plastic plugs; I may even undo what I did here and use an actual servo connector to make the power connection easier, but only if I end up plugging and unplugging it several times. Even though it won't be as clean, I'll probably just loop the receiver harness because i don't have crimpers and pins to shorten it.
It's beginning to look like a quadcopter.
@djslack I guess it really doesn't matter, but I put the pdb above the arms and putting the CF piece at the bottom. If you land on a shopping cart or a car, you can short out the underside of the pdb unless you somehow insulate it.
@garyhgaryh I started it that way, then changed my mind as I wanted as much wiring hidden as possible. That, and since I'm skipping the rgb leds for now, running the pdb on bottom exposes the included light bars.
I also currently have the included landing gear on the arms, although they may come off. I've been thinking about spraying the bottom with plasti-dip when it's done, as well as investigating hydrophobic coating for the cc3d board as it's exposed and caseless in my build.
@djslack It looks great man. You've really accomplished quite a bit.
@ruouttaurmind Thanks! It's coming together, I may have a hard time waiting on camera equipment for it, may just have to weight it for test flights.
Days 6-8: sparse work here and there. I got all the ESC wires routed around the arms with the plates sandwiched together. I used two nylon screws per arm stuck up from the bottom as sort of alignment pins. I then used a pick tool to push and pull the wires from the various access holes until I could see that they all went around the arms and wouldn't be pinched.
I then screwed the final bolts and nuts through the other two holes in each arm, removed the nylon screws and replaced them with the supplied bolts and tightened everything down.
The wiring harness supplied with my cc3d didn't match that on Openpilot's documentation. There are two blue and two yellow wires, and the white wire with the power and ground wires doesn't go to pin 3, but instead to pin 4. I opted to follow the cc3d documentation and connect the signal wires to my receiver by pin location. I looped the wires in a loose knot to take up the slack, i hope this doesn't cause any induction issues. I tacked the rx down with double sided tape.
I also wired my voltage display up to the battery pads on the pdb, running the wires up next to the standoff to the top deck and fixing the display with double sided tape.
The pigtail for the battery is way too long. I'm going to remove it and solder a male connector directly to the extension leads, putting the power plug maybe a half inch outside the back of the lower deck. This should make the wire length just about right. The hxt60 connector on the pigtail is much easier to remove that that on the Phantom, which is a welcome change. It still feels secure, you just don't have to fight to break it loose. I hope the individual connectors I ordered work that well, as that's what I plan to use.
I'm going for as few exposed wires as possible. The camera will add a couple more, and possibly a few more than that depending on whether I go with the board camera and vtx or the ilook camera @ruouttaurmind is sending me. But so far it's fairly clean. I may break down and get the tools to repin that receiver harness and trim all those wires to length, but that'll be down the road.
BTW, PDB guys, I don't know if this was as non-obvious to you as it was to me, but I just realized today the tiny solder pads along the side of the fc are for the esc signals - they each terminate at another tiny pad at each corner. Since I turned my fc sideways they don't line up for me (and I'm actually running mine backward to have the 5v at the rear by the rx and 12v up front for camera). But if you're exposing the pdb up top, this can clean up your wiring.
It would have been nice if any of this kit came with even a one page quick documentation set. Figuring it out has been fun, but a quick sheet with the kit and one with the PDB would have made a lot of things very clear very quickly.
@djslack Wow! Throw some rotors on that sucker and send it up! :-) I had the same issue with the CC3D harness colors not matching the CC3D documentation. I followed the docs and ignored colors, matcing the pinout. Everything worked as designed when I installed it in my (previously) crashed QR X350 Pro a couple of weeks ago.
@djslack RE: the solder pads on each corner and the row of pads on the edge... I did a continuity test and found they each trace to the row of pads on the edge, but it didn't occur to me they were intended for ESC signal. Great find to figure that one out! I searched high and low for some kind of documentation for the PDB and have found nada. Thank you for the tip! I think I'll put some header pins on the ones along the edge and put them to use.
Day 9: fought with a bad mini usb cable for a while, tried gcs software on my tablet and laptop but they couldn't detect the fc. Finally tried a new cable and got gcs to work.
Went through the setup wizard and I have a problem. When setting idle speeds Motor 1 would not spin. I set it the same as the others to get me through setup, thinking I had a bad solder joint on its signal wire. It passed the test before I disassembled everything, but I wasn't paying attention to idle speeds or throttle position; just a quick up and down to verify they spun and in the right direction.
When I armed the quad and ran up the throttle, three motors spin. At about 55-60% throttle motor 1 kicks in, and doesn't spin as fast as the others. It doesn't sound bad, but it sure won't fly like this. Now the question is, do I have a motor problem or an ESC problem?
Problem solved. Redid the ESC calibration, all motors spin up harmoniously now. Somehow the esc calibration must have gone wrong in the configuration wizard.
A little work on the pigtail, some prop balancing, and a few touches here and there, and she should be ready to get in the air!
P.S. I was worried about not having a calibration harness to plug 4 ESCs in at once. Calibration is trivial with the GCS software. Enable live testing of the motors, set throttle to max across all channels, and plug in the battery, then set throttle to zero and calibration is done.
@djslack Great work, great thread. Lots of useful info here. Looking forward to seeing the first flight test video!
@djslack Your build is much cleaner than mine. I'm jealous! :)
@garyhgaryh Thanks! I'm currently puzzling over wiring the camera and vtx, all that exposed wiring bothers me.
I'm going with the surveilzone cam and TS832 transmitter, the whole setup is 30g lighter than the ilook and I can mount the camera within the frame. Unfortunately the vtx doesn't fit between the frame standoffs. So far I'm thinking I can move my voltage meter and put it in the back on top, or I can mount it sideways under the upper frame.
Day 10: Haven't gotten to touch this project for a few days. Last night I balanced props and soldered in some wire from one of the removed esc leads to the 12v pads on the pdb. Planned on using the dupont connectors to connect to the pins in the JST harness for the iLook camera.
Installed the vibration dampers to the camera platform, and the platform to the frame.
I also removed the pigtail from the battery leads and soldered an XT60 connector just outside the rear of the frame on my wires that connected to the pigtail previously.
Day 11: My surveilzone order showed up after lunch today, so I weighed the board cam/vtx/wiring (50g) versus the iLook and wiring (80g). I'd been playing with mount ideas for the iLook since last night and hadn't come up with anything better than zip ties to the camera platform. For weight and a clean setup I decided to go with the original plan for the board camera and ts832 transmitter.
Trimmed the camera board down to the inner 32mm size. Drilled out the holes in camera board and cf mounting plate to fit the nylon screws I have, it took a 1/8" bit.
Thought for a bit about vtx placement. The ts832 is too wide to go in between the standoffs on the frame. I thought of moving the battery display from the top rear and mounting the vtx on the top rear. The way the antenna connector comes off the vtx that end has to be hanging off whatever it's mounted to. This position would end up with wires running from front to rear for both power and camera.
I opted to try mounting the vtx sideways, under the top frame with the antenna coming out the right side. This keeps all the wiring short, within the first set of standoffs. It also puts the antenna directly above the tip of the front right prop. I don't think the props flex nearly enough to hit the antenna, but we'll see. I could use a smaller antenna with a fixed 90 degree bend and not be over the prop.
Because I'm not sure how well this will work, I left the camera harness intact and the power wires long and did everything with zip ties. This prevents me from using the upper camera platform as I'm using the holes it mounts in for zip ties. If I keep this arrangement I'll work the mounting out better.
Tomorrow I'll work on battery mounting. Not sure if I want to use Velcro or straps. If I had straps on hand I'd use them to keep from putting Velcro on my packs. I might even try to make some Built NY straps.
I want to keep the upper platform so I can mount my Midland action cam from Meh to do recording on occasion. This will wind up being 50g heavier than if I just used the iLook, but it won't be on there all the time and it requires no wires. The Midland 720p cam with battery weighs the same as the iLook and wiring.
@djslack thanks for the update.. Love the pics. Keep 'em coming
@djslack It's clear how much thought and effort you've put into keeping it clean. Very professional looking build!
@ruouttaurmind @garyhgaryh Thanks guys! Hopefully it all comes together and gets in the air today.
Day 12: One battery strap made, there's really only room for one with this battery (it rides more forward than shown in the pic to get the cg right) but a second is in progress. If you bought Built NY cases from Meh you might recognize the neoprene:
Quick tip: the sticky back Velcro is not meant to also be sewn. You end up with glue all over your needle and thread. But glue is no good on stretchy neoprene, the Velcro also needs to be at least tacked down for structural integrity.
I can't resist, booting up the gcs to quickly verify which pids i loaded and going out for a test hover.
@djslack Let's see! Video or it didn't happen... ;-)
@ruouttaurmind
So I'm trying to figure out what exactly happened here. Either power glitched or the front right prop did strike the antenna. There aren't any marks--anywhere. Either my get out of the throttle reflex is really good, or all the escs shut down for some reason (radio failsafe?)
The vtx to camera wire loop got snagged in the front left prop when the antenna pushed the vtx to the left when it hit the pavement. The wires were around the prop but unharmed, so i know the prop wasn't powered at the time.
The rx case (safely caged in the rear) was popped apart. At first I thought my double sided tape had failed. No damage noted, snapped it back together.
I hooked it back up inside in the light, armed it and spun it up, everything appears normal. Man, this thing is loud, and it really moved some air in my kitchen.
I need to investigate what the receiver does for failsafe and see how to control that.
So I secured the vtx and wire loops better and took her out for another spin. This time not trying to hold the phone and fly at the same time. I also flew over the grass instead of out by the light.
Hovered for maybe two minutes. Noted a bit of roll oscillation, pitch seemed good. Yaw had a little drift to it, very slow and it might have just been my thumb's fault.
Just about the time I started to get comfortable and consider taking it for a circuit, it did the same thing from about 2' high. Roll right, crash inverted. This time the front left motor stayed at idle, all others had stopped. I pulled the battery and called it a night, i have work in the morning.
@djslack Wow, it looked great before the incident. I have to say, as crashes go (and I'm a guy who's very experienced in that subject) it looked pretty clean.
In slow motion you can see that it completed it's inversion before hitting the ground. Watching frame by frame it looks like the port side just... stopped, and the starboard side continued to run causing an inversion. My Syma X-1 has flips built into the firmware and yours had exactly the characteristics of my Syma when I execute a port side flip. Well, except the Syma continues around of course.
No damage to speak of? Looked like it hit pretty square on the lid.
@ruouttaurmind No permanent damage at all. I can't even find a scuff from the concrete. I think it landed squarely on the vtx antenna (which folded/moved) and then the cushy neoprene battery strap.
I'll be researching it until I can get to play with it tomorrow after work. I'll hook up gcs and get it to display my radio inputs and try to simulate the failure to see if it's a radio glitch.
@djslack Wow, congrats @djslack! I'll post some pics before I go to sleep. I have a wake up early tomorrow so no more working on my zmr250 tonight.
@djslack Is there a way to initiate a flip on the cc3d? Perhaps you initiated it, but it was too low to do that? Wishful thinking on my part?
@garyhgaryh only full stick in rate mode or rattitude mode, that I'm aware of. I was flying in attitude mode so there shouldn't be any inversion or any sudden moves like that.
Day 13: Made up a safety rig with string threaded through the landing gear holes, tied to the posts of two of our patio chairs. It's not perfect but it keeps it from going anywhere. Tested live display of radio input but it's super laggy (updates maybe 3 times/sec) and wouldn't show a brief glitch unless I was lucky.
Armed and flew. No real problems until I gave it right yaw input, at which point it immediately fell off in what surely would have been a roll to the right. When I killed the throttle, #1 motor stayed up at idle.
Swapped #1 and #3 connections at fc, problem followed motor #1, indicating the esc. Recalibrated escs and tried again-had to set the idle level way lower on #1 than on the rest (1006 vs 1065). This is weird because before they were all 1023 across the board. Lowered sync rates from 490hz to 400hz then 330hz with recalibration each time. Behavior is the same, including the lower idle level for #1, so I'm thinking I possibly have a bad esc. Wondering if I should write the vendor and see if they'll ship a replacement. I'll have at least 2 weeks of testing time if I take that route.
When I give it right rudder it immediately falls off to the right. When I give it left rudder it gives #1 and #2 motors crazy throttle up. Not sure what that means but it doesn't seem right. Maybe something is off with yaw on the fc.
@djslack That is odd behavior. Did you do a manual ESC calibration or did you use the OpenPilot routine? I was getting inconsistent responses with OP GCS so I switched to manual calibration and had MUCH better luck.
@ruouttaurmind i used Openpilot's routine. I figured the throttle signal is being generated by the fc, the raw throttle from the rx is never making its way to the escs.
Do I need a 4 way board to do a manual calibration? I can't do it through the fc, but have to go directly to the rx, right?
@djslack I connected my ESC to the RX Throttle ouput. Powered on my TX and set it to full throttle, then powered up the radio. You'll hear the ESC pulse the motor a couple times, then go quiet. Now reduce TX throttle to minimum. ESC will pulse motors again, then go silent. You're done. Repeat for each of 4 ESC. EDIT: I wrote "powered up the radio". What I really mean is power up the ESC, which in turn powers the radio RX.
@ruouttaurmind Thanks. That's what I thought manual meant I'd have to do. Because of my tucked wiring I'll have to take it apart enough to remove the fc. That's going to be a project for another day.
Day 14: didn't have time for a teardown to get to ask the wires to calibrate escs manually, so i erased the board and set everything up from scratch just for grins.
Everything is the same. Three ESCs calibrated right on the money, #1 is off and neutral is far lower than the others. Flight behavior on my string rig is still the same, and the #1 motor stays running at idle when I shut down the throttle, or even when I disarm the fc. It looks like the #1 way overspeeds on control input which would make it always flip to the right.
I just wrote the seller on Ali express asking about the defective ESC to get that ball rolling. Will start the teardown next.
They have asked for a video so that's what I'll be doing tonight. I'll post it here as well in case anyone has any ideas.
@djslack They will ask you to do a manual ESC calibration after you send the video. I went through all that with them on my bad motor. After four replies from them asking for something different every time... and video proof of the process... I finally had to get pissy and chastise them before they finally agreed to send a new motor.
Hopefully you won't have to go through all that. But since you've got to disassemble to replace the ESC anyway, might as well do a manual calibration while it's apart so you can tell them "yes, I did that"
@ruouttaurmind did it take them forever to get back to you? I emailed the link to the video the same time I posted it here, with no response yet.
@djslack You have to co!tact them through the Aliexpress messaging system. Login to Aliexpress then go to your account and select Messages. I tried sending email but never got a reply until I used the Aliexpress system.
By the way, I received my replacement motor today. It took me about 10 days and half a dozen emails to convince them my motor was bad, but once they finally shipped the new motor it arrived in 6 days.
@ruouttaurmind Thanks. Crap. I just replied to her email asking for the video.
I'm thinking i might try to speed it along by offering to buy an additional extra motor and esc and a couple of spare arms. I could use spares anyway and they may be more inclined to go ahead and send me replacements if I'm sending a little money and getting more stuff.
@djslack that's what I would do, but I'll wait for her initial reply first.
@djslack You may be right. They asked me to buy more stuff while they were considering replacement of my motor. I checked their store, but didn't really see anything I wanted at the time and just told them "Thanks, not at this time, just the motor". Their next message included the tracking number.
Day 15: I made a video tonight. It's uploading from my phone, and says it's going to be a while.
While filming, the #1 ESC glitched out and recalibrated itself when it wasn't supposed to. So I went through yet another calibration on camera.
After "flying" for the video I also noticed that the #2 motor was quite hot, all others were at room temperature. Maybe I have a bad motor, too :(
Here's the video, for anyone that cares to watch:
@djslack Thanks for the video. I hope the seller sends you a new motor and esc. I like your string setup. I'll try flying my zmr250 this weekend on our lawn. If it acts erratically, I'll suspend it on strings like you did (ingenious :) ).
@garyhgaryh Thanks. When researching I read that someone said they used strings and sawhorses to bench test their quad. So I can't take credit, but i hope it helps if you need it.
My thoughts with it were to have enough slack to see what it tries to do, but tight enough the props won't catch a string.
They wrote back yesterday and indeed asked me if I had calibrated the ESC manually. Stated that if I did that and it still didn't work, that they would send me a replacement ESC.
They also asked me if the motor mount screws were too long on the #2 motor - mine are not at all.
Here's the video I took of the individual motor testing. One thing I notice: even on the two "good" motors, there is a difference in speed at full throttle. I don't have a tachometer, but I have a snazzy ukulele tuner and it tells me that at full throttle #3 spins just below an F, and #4 spins just below a D. The #1 spins at about half the speed of a "good" motor, and #2 begins to stutter above half throttle - this would be the culprit behind my flips to the right. What I don't know is whether it's a bad motor or a bad ESC.
I noticed when going back through AliExpress after writing the seller a message that these kits are on sale now for a few dollars less - $82 in my case. It's cheap for what you get, but I think their quality control seems a bit lacking. We're 2 for 3 on this forum with issues out of the box in what should be a random sample. It might be better to spend a few more bucks to have a better chance at flying on the first try. I'm tempted, I filled a cart with another $50 worth of stuff (two spare ESCs, a spare pair of motors, and a spare frame because I didn't see just arms for sale) but I don't know if I'm just throwing good money after bad buying spares of the same stuff that is giving me problems now. I might do better to go buy a set of motors and ESCs elsewhere and redo them all. I might buy a spare frame anyway, though - it's on sale for less than $20.
@djslack I think your money might be better spent buying those same items from readytoflyquads.com or getfpv.com. May not be the same frame though so not sure how swappable it will be. But from what I've read the quality control is better.
Ready to Fly is where I'm ordering my replacement and spare ESCs. $10 for a good ESC vs. a set of 4 ESC's for $24 that from our collective experience may have some bad ones :(. Plus US based company so it will arrive quicker. I'll spend the $4 for quality over quantity.
@djslack If you decide to strip the ESC's and motors and start over, consider downgrading to the 12A ESC's. They're a bit smaller, lighter, and more than capable for these tiny little motors. 20A turned out to be massive overkill, and SO BIG. That's what she said.
@DJMajickMan, @djslack I've bought (too much) stuff from RTFQ, and while the quality is fine, it's not necessarily quick, even though he's US based. I don't know if he's overwhelmed, or if he's waiting for China, but I'm not impressed with the speed. Maybe I'm spoiled by Amazon...
@fultonmartin We're all spoiled by Amazon Prime :D
@fultonmartin Everything I've ordered from US suppliers, or purchased locally turned out to be identical to the items I've purchased from China. And in many cases, only a few days quicker than China. Even my last order fulfilled by Amazon took just over 2 weeks to arrive (no Prime here).
@ruouttaurmind almost same experience here.
@ruouttaurmind Yesterday the seller got back to me and asked if I'd played with switching everything around to determine which things are actually bad. I haven't had time to mess with it, but guess I'll be disassembling this evening and weekend.
Day whatever: I spent some time this weekend getting up close and personal with my ESCs.
First up was motor 2, because the problem was less weird. I cut open the heat shrink and immediately found a problem: the lead coming from the second set of FETs on the ESC wasn't soldered to the board anymore!
Remember the problems I had tinning the leads? I took@ruouttaurmind's suggestion and went and got some acetone to remove the coating on the wires. Apparently scraping with an xacto knife wasn't enough. That done, the wire tinned fine and soldered back into place. Tested the motor connected directly to the receiver with good results.
I was then faced with the problem of getting heat shrink back on the arm. I did this work without removing the arm, and if I had to remove the arm then I would have to desolder the power leads and remove the ESC signal wire. Instead, I saw that if I took the bell housing off the motor, the heat shrink should fit.
This isn't as hard as it sounds. Pop off the retaining clip from the bottom and the shaft will push right out. The first time I did it, disassembly and reassembly probably took 5 minutes. By the last time I did it I could remove and replace the bell housing in under a minute. It would be super easy if you weren't doing it through the little hole in the arm.
On to problem child #1. Disassembled the same as #2, don't notice anything immediately awry. The #1 motor is the one that had leads crossed, causing me to miswire it the first time around and subsequently use the traces on the ESC (using the traditional motor lead solder points instead of directly to the FETs as they came wired) for the lead that was cut too short. The first thing I did was extend that lead and go back to the original solder point, with no positive results.
Next I switched motor #3 with #1. The problem remained with ESC #1. I started comparing the ESCs under the magnifying glass and saw a solder bridge on #1 that was not on #3. It was on the backside of the very tiny resistor(?) near where the signal lead is soldered to the ESC - the opposite end of that component from where the wire is connected to the board was bridged to the larger component next to it. I removed the bridge with some desoldering braid and got success!
The #3 motor is the one that seemed to spin a hair slower than the others, and this stayed with the motor at the #1 position. It doesn't seem to affect flight, though.
I reassembled everything, wiped the FC and set up from scratch, again on a string rig. Tested to full throttle and with full control inputs and everything seemed to behave as intended, so I took it out for a flight!
Here's crappy video made by holding my phone behind the transmitter, resulting in loud throttle clicks.
And I got all this done just in time to leave town, so I can't play with it for the next three days.
@djslack Wow! Great detective work Chris! Good job locating and resolving those issues.
The flight video was AWESOME! These things just SOUND fast, innit? Yours looks like it's pretty stable. You've done some great work!
By the way, I get my acetone at the dollar store in the form of generic nail polish remover. The cheapest, no-frills stuff is nearly pure acetone. Ninety-nine cents for 6 ounces.
@ruouttaurmind Thanks! It is pretty stable. I was testing control inputs, got pretty heavy on the side to side as you saw. Didn't go forward as much because what you couldn't see in the video is my neighbor's car about 10 feet away. I did test flying around in the circle after I put the camera down, it seems solid and I can't wait to get some daytime flying in. Hopefully my eachine camera/vtx kit will arrive and I can clean up that vtx arrangement with the smaller unit.
I used the QAV250 presets in GCS. Once I get the hang of flying it I'm sure there will be room for tuning the PIDs to get it nice and snappy, but it's plenty responsive with those presets from the few minutes I have on it.
@djslack Hell ya! I was grinning from ear to ear watching you fly your drone. Congrats on fixing your issues. It seems your zmr 250 is so much more stable than mine. Either that or you have better flying skills than me. :) I'm really happy you got issues resolved.
Can you do me a favor and measure the resistance between all your motor mount screws to battery ground?
@garyhgaryh Thanks! It's an open circuit on mine.
Which presets did you use for your FC?
@djslack I used the "Chinese ZMR 250". It was one of the last ones in the profile list. Mines are def. not open circuit (the rest. between the mounting screws and battery ground) .. :(.
@djslack Which motors do you have on your zmr 250? 1806? 1804? 2204?
@garyhgaryh I have 1806s, which is why I went with those presets, it seemed the closest.
You probably have battery ground touching the frame somewhere-a thick solder joint to a pdb or something might be likely. It's probably not harmful, most vehicles operate that way on purpose.
@djslack I'll leave mine the way it is (at least for now) since my quad is up and running.
@garyhgaryh From an electrical standpoint, it shouldn't hurt anything. "If it ain't broke, don't fix it" sounds like a good plan to me. May you never have a reason to tear it down and find the short.
Got my first real flight in today. Have to get an adapter to get the Quanum V2 goggles to plug into the VRX, so I flew with the screen for a minute. Video signal kept pulsing to white, not sure what that's about, so I just flew a pack LOS.
Here's proof:
@djslack "TREES!" That was awesome! Its pretty peppy in the air, innit?
@ruouttaurmind It's stupid fast. Exactly how i wanted it. I'm embarrassed because I flew the rest of that pack with no loss of control. I think I didn't give it enough throttle when I flared back to slow down, and was worried about keeping the camera on it more than flying it.
It flies great! Super responsive. The slow motor does show itself in flight--if I punch the throttle for an all out climb, it veers off to the left about 10-15 degrees. But in normal flight it appears to compensate pretty well.
Stuck the Meh special Midland Action Cam on the clean plate today and took it out to fly a pack. I went to a big open field because I wanted to go fast, but flying line of sight this thing gets too small too quickly, I chickened out on going very far and upon reviewing the video I didn't use much of the field at all. Next mission: get the goggles working.
Pack was a 1500mAh Turnigy 3S. I kept coming back to check my voltage meter on the back of the quad. The last check I saw 10.6 so did one more fast pass out and back, and when I came back it said 9.97, so I set it down fast. I didn't want to go much below 10.5. But a solid 7 1/2 minutes of flying is not bad, it would still get over 5 minutes if I ran it hard the whole time.
@djslack Good video. Is it just the camera perspective, or does that thing turn on a dime? The video it makes it look like it spins around on rails.
What do you suppose is the solution for visibility? More LEDs? Paint it fluorescent orange? Flashing lasers & roman candles shooting out the sides?
@ruouttaurmind I don't think it's just the camera. There is a dizzying moment when I did 2 or 3 360's in a row just to see how fast it would spin with full control input, and it's fast. A couple of my fast passes back towards the road behind me, I did quick turns and stops and it's very maneuverable. This is on the base settings, I haven't played with any of the tuning or different modes in GCS yet (though I'm itching to put Rattitude on a flight mode and get some flips in).
More LEDs may help with visibility, flying higher wouldn't hurt either. But honestly my solution is just to go FPV. I want to see zooming along fence lines or under tree branches from the quad's perspective, anyway. I could cover a lot more ground with a good FPV link and not worry about losing my orientation.
I finally got my first fpv flight in yesterday evening just as the sun went down. I've got to say, that takes some getting used to. I think I flew for 2 or 3 minutes. I don't get motion sickness from games or anything, but I definitely felt disoriented and a little queasy from the goggle view. I then switched to a monitor for my friends that showed up to be able to watch.
Next plan is to go find a pretty deserted place. Learning FPV I think is going to require a large open area with (a) no places I'd have a problem retrieving a downed quad - like other people's fenced yards, and (b) a low likelihood of drawing spectators. This hasn't happened but I can totally see it at any of the little places in my neighborhood. Time to go to the country.
Yeah I just got up to PA for some vacation time and put together my 250 FPV. Will be posting a thread for that later. Major issue is the "Hoity-toity" people up here who get up in arms about everything are full on anti-drone with statements of we have to many small craft airports in the area etc. etc. One of those airports is not even an airport it's an abandon landing strip.