Yesterday we finally observed the first moves of our octocopter. After spending all the day working on the communication with the motors, Samuel and Axel have succeeded in controlling the motors from the STM32, with the help of Jon, passing by. They speak to them in I2C, and they can control the speed of the propellers. The Copter tried to run away, but he was fortunately attached on a table. However, we have to be more careful in the way we will attach it in the future, because it was close to a disaster.
On my side, I tried the RF controller, a Spektrum DX7 transmitter/receiver. I tested it on the STM32 board that we have previously use for the communication challenge, it works as we can expect, thanks to the code of the Heliokter team. We use indeed the code from last year’s project, which seems to fit to our needs. The RF receiver gives us access to different integers, which indicate us the pitch, the roll, the yaw and the thrust, and also some commands. The way the receiver communicates with the PCB is simple : it use the RS232 protocol, with a speed of 115200 kbps. It sends packets of 16 bytes separated by long period with idle line. I have implemented the code for our PCB and for getting the commands on the Gumstix, but I still need to test it.
On his side, Bertrand principally tried to debug some aspect of the STM32 code. When we send data in the both directions and look for the values of the sensors at the same time, some freezes occur. We think it’s maybe because the code needs some optimization, so Bertrand is working on it.