Sunday, 10 August 2014

Mini FPV mobius quadcopter

This is a build log for my new mini FPV quadcopter. Everyone is crazy about these ~250mm mini copters right now, so I wanted to give it a try...


Parts list:

Some photos of the complete build:

375g weight without battery

I only had these old nanotech 3S 2.65 Ah batteries lying around. a bit heavy at 212g.

589g AUW with the 3S 2.65Ah nanotech. It draws about 11A at hover. Only a little above 50% throttle. I am surprised how well the EMAX motors work. They are not even warm after flight. I might try 6x3 inch props.







APM 2.5 / 2.6 voltage regulator fix

Two of my APM boards have blown their 3.3V regulators. It is a common problem with APM boards and might be connected to plugging in the USB cable whilst the board is powered by the flight battery. There is a lengthy discussion thread on DIYdrones here: http://diydrones.com/forum/topics/ac3-1-rc5-spi-speed-problem?commentId=705844%3AComment%3A1457284

I got this for a replacement: http://www.coolcomponents.co.uk/voltage-regulator-3-3v.html
A little bit overkill, but it was cheap and available around the corner.

Here is an excellent video showing how it needs to be installed:
https://www.youtube.com/watch?v=5Ur_s2inGHY&list=UUlCZWv9dKygCflwty9_s8Sw
It is in German. A little summary:

  • remove the blown regulator. For me a combination of soldering iron and brute force did it.
  • add three short (few cm) servo wires to the regulator and wrap in heatshrink
  • solder the output to the capacitors on the APM board
  • solder ground and +5V to the side of the APM board. Labels on the underwise

Now my dead APMs are alive again! For less then two pounds!