UAV with Chumby Hacker Board – Quadstruction


It’s been awhile since my last build log post, but I’ve covered a large milestone. See my previous posts:


UAV with Chumby Hacker Board – Configuring a CHB

UAV with Chumby Hacker Board – Frame & Material Selection


Following up on my last post, my plastic pieces were ordered from Ponoko: two main plates made out of 3.2mm white Delrin plastic, and the carrier boards, motor mounds, and battery mount from 2.3mm white Delrin. I enlarged all but the motor mounts in order to scale up the size of the carrier boards to cleanly fit a Chumby Hacker Board (CHB). One addition I made to the main plates was adding a set of extra holes (inner holes) to line up with the standard power distribution board. I also used the standard 28cm by 14mm square tubes for arms.



The battery holder was enlarged in order to use the outer set of holes so that it wouldn’t get in the way of the power distribution board using the set of inner holes. I went through Hobby King’s stock of 3S 25C LiPo batteries to find approximately 5000 mAh while keeping it as light as possible. I picked out two Rhino 2350mAh 3S1P to tie in parallel for a total of 396 g. I can use only one battery if weight ends up being a problem.



The power distribution board from fits right in between the two main plates. As you can see from the image below, in order to make it fit I replaced the right-angled pins with a connector. I’ve read that some people have issues with the power distribution board causing interference with the compass, so this should alleviate it a bit by putting more distance and plastic between the two.




I still used a 10mm standoff from the main plate to the first carrier board to leave some clearance for Velcro. On the first carrier board lays the APM+IMU+Magnetometer and the radio Rx. I went ahead and ordered a sample of the Tempur-Pedic mattress foam and sliced it roughly 7.5 mm thick. If you haven’t found the thread on here, you cut it by freezing it and then cutting it with a bread knife. It may take a few rounds because it ‘thaws’ quickly.




The next carrier board up has the CHB, GPS, and XBee. I just completed building it so I haven’t fully tested to see if there is too much interference with it being close to the GPS unit. The CHB requires 5 volts so I use the DE-SW050 regulator tied to the distribution board. I also got the GPS connected via FTDI to the CHB for my WiFi stumbling project. 



Here is an approximate weight breakdown…

CHB+5vReg+WiFi: 57g

APM+IMU+Magnetometer: 42g

GPS: 8g

XBee+Adapter: 10g

Radio: 18g

ESC+Motor+Prop (x4): 332g

Frame: 418g

Total Weight without Batteries: 885g

Battery (x2): 396g

Total Weight with 2x Batteries: 1282g


Here is a zip with my EPS files I sent to Ponoko:


Things I’ve learned:

One mistake I made throughout this project so far was not ordering enough parts the first go around. I eventually found that Amazon sells bags of 100 M3-.5 nylon screws and nuts that work perfectly for about $6 per bag, which is the cheapest route for hardware I’ve seen in you live in the US.


I also learned that the Deans Ultra plug connectors and I don’t get along well. I ended up going to Radio Shack in a fit of rage and bought a bunch of 2 pin Molex connectors that work really well.

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  • Sebastian, maybe the biggest but not the heaviest....but then there's no datasheet to compare the Deans with the PowerPoles....
  • @Russel

    I'm estimating 8 minutes with 1x 2350mah battery about about 14-15 with 2x 2350mah batteries.



    I took the standard DIYDrone frame and made it a bit larger. I don't think I added too much weight so I figured I could use the standard motors and props for it. I might just get a little shorter flight time.

    The Chumby board will need about 400 ma of power. I will eventually attach the APM to the Chumby, however for now I'm only connecting the GPS directly to the Chumby. Thanks for the tip on disabling the auto-reset.

    The APM is fixed on the carrier board. I'm using the 3 screw holes as well as Velcro to level it out a bit. Since there are only 3 screw holes, the board sits a little cockeyed with the Tempur-Pedic foam.



  • so you sized up everything but the motors/ESCs and PDB? no good idea....

    how much power does the chumby board need? you could go with a BEC from one of the ESCs if it is less than 2A

    do you want to connect to apm with usb? if yes, i would try to disable the auto-reset funktion of the apm (if the hacker board reconnects, your apm will reboot, which would cause your copter to crash immediately)


    your apm board doesn't look like it's fixed on the frame... remeber, it has to move just like the frame under all circumstances.


    @happy: and may the biggest for no reason...

    just check these here:

    about 1.6cm width and 2.4cm long, for ONE side 45A (about 4cm for both sides, just guessing here..)

    and now take a look at the XT60s: 1.6cm width and 2.4cm for BOTH sides connected together , 60A

  • What is the estimated flight time with this setup?


  • The XT60's are essentially bullet connectors with a plastic housing. You can't go wrong with those either. I personally hate Dean's connectors and can't believe they've become the defacto standard for R/C connectors will all their shortcomings.
  • Thanks for that. I think I'll give those a try! I was going to order some XT60s, but I trust your recommendation.

    Also, any comments on the weight of the frame? I'm not too sure on standard/average frame weights.
  • For future reference....Anderson Power Poles may be the greatest connector ever made.


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