MicroQuad Update #5

I’ve done a lot since the last update.  The motors are working well, as are all the ESCs, but I have been tackling a noise problem with signal crosstalk.  Through lots of troubleshooting and frustration, I swapped out the old wires for a color-coded twisted cable and added a 0.1uf capacitor for each ESC.  This got rid of all the noise but several motors weren’t responding.  After checking all my connections, I re-soldered everything and found that the PCB is defective and one of the traces was ruined, leading to no signal contact.  The new PCB should be here any day now, its been about two and a half weeks.

Speaking of which, the Spakfun PCB forum was extremely helpful for finalizing my design, I’ll list the changes when they come in.  The fresh Digikey and Sparkfun orders came in, this time with the single power regulator, a magnetometer, and GPS with antenna.  Version 2 is going to be so much better, lighter, smaller, and more awesome than the first one with completely integrated control and inertial measurements on one thin, small board.

And now for the bad: Waiting for shipping is awful, as usual, and HobbyKing has been out of stock on the 0.3g ESCs for over 3 months now!  I can’t order replacement propellers either, since I broke one of those as well.  Gahh!

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6 Responses to MicroQuad Update #5

  1. MiBoRC says:

    Your single-board design sounds really cool! I’m trying to do a nano-quad that consists of a single PCB and four motors (the same ones you’re using). I’ve been suprised at how similar our designs are, although I suppose there’s not too many ways to do it right! The major differences are that I’m trying to use a much smaller PIC (the 16F1828), and I’m using BLDC controllers instead of ESCs. Your choices there may turn out to be better, though. Thanks for sharing your project!

  2. ebperrin says:

    What BLDC Motor controller ICs are you using? Keep in mind the motors are only 3.7v tolerant. I haven’t tested them at 5v, but I’ve done some searching myself and can’t find any 3.3v driver ICs, which is why I resorted to the HobbyKing ESCs. You can see some more pictures at my build thread:
    http://www.rcgroups.com/forums/showthread.php?t=1547273

  3. MiBoRC says:

    I’ll be using the Microchip MTD6501C. Datasheet is here: http://ww1.microchip.com/downloads/en/DeviceDoc/22263A.pdf

    The biggest problem is that it’s only rated at 800mA, but hopefully that will be enough to get off the ground. Have you done any current draw measurements on your motors? I am waiting on mine to get here so I can test them.

    I think I’ll have enough thrust, since my projected total weight is only 20g. We’ll see, though.

  4. ebperrin says:

    I haven’t done current tests yet, but my new boards just came in so as soon as they’re built i’ll be able to get some current tests done. 800ma is really pushing it for doing some quick maneuvers. You’ll see current spikes at start-up and on collisions, I would go with something bigger if you can find it just so you won’t be constantly smoking them.

  5. MiBoRC says:

    The next step up is this:
    http://www.toshiba.com/taec/components2/Datasheet_Sync//379/28124.pdf
    Which is way bigger than I want to go for my model A, but exactly what I’ll use for model B. I plan on having good smooth motor control to keep the current spikes under control, and the controllers do have over-current protection. In theory it will be able to take off and hover, although flips might be out of the question.

  6. ebperrin says:

    Definitely a start. The bigger ones you just linked only run at 7v minimum though, odd considering their low current capability. I’m not sure if you could find a 2A motor that runs at 7.4v while keeping the whole setup light. The guy in this thread: http://www.rcgroups.com/forums/showthread.php?t=1600876 is trying to develop an open source motor controller at some point, which the entire micro community has been needing for awhile. If I haven’t mentioned this before, my alias is BudgetEngineer and I’m 14 years old.

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