The song “Party Rock Anthem” by LMFAO has almost 690,000,000 views. What is this world coming to?
But, I got a quadcopter last week! It’s 3D Robotics’ quadcopter kit. Which is a very nice kit, but let me warn you it includes neither a PPM R/C system nor a battery, both of which are required to make it run. So if you get one be sure to get those also, unless you can rewrite the firmware to not have that necessity.
The instructions were clear enough that I was able to put it together in a couple of evenings after work, without screwing anything up. However, getting the software stack to run on Linux took some doing (and all of Saturday). A note for future users: I had good luck with the APM Planner 2.0 software (compiled from source) running the default APM Copter firmware. My receiver is a Spektrum DX6i receiver from back when I flew model airplanes, and the satellite radio works just fine although I will be doing range tests next weekend. At the same time I put a Raspberry Pi and a webcam on it.
As for the battery, for reference, I went with the nano-tech 3 cell 2.2AH LiPo battery, which goes for just under $30 at Hobby Town.
Something to be wary of: The default APM Copter firmware doesn’t have a very good battery monitor (or maybe I misconfigured it), and LiPo batteries dislike being overdischarged. According to the internet once you get below 3V/cell (9V for a 3 cell battery), you just have to toss the battery unless you have a charger that can charge the individual cells at 5 milliamps or whatever.
Here’s what I did, which worked for me although my battery probably doesn’t have as long a life as it could have: I plugged it into my regular charger, set it in the lowest mode (1A), and started a charge cycle. It went for about a minute before it noticed the battery was undervoltaged. I reset the charger, checked the cell voltage and balance using a volt meter, and started a new cycle. This went on until eventually the battery gets back to 9V, at which point I went to the 2 amp mode on the charger and fill the battery up fine.
Of course, I kept a close eye on my battery during this process and you should too.
On a lighter note, I kept on having issues with my quadcopter flipping over:
Turns out that the preflight calibration was messed up, and the onboard gyros were off by 20 degrees.
But, yesterday, I managed to get the GPS-based modes working (specifically loiter and guided). Loiter mode is rock solid, even in 10 knot wind. Kudos to the guys at APM who managed to make that work.
