Hi, I am building my third Elegoo Arduino-Mega 2560 based Astromech. I am using the exact same code that works fine on R2-D2 (my first astromech) and the same power method. I power the board on the droid with the barrel plug on the Arduino connected to the droids 12V power supply. I have two 3S 5000mAh lipos hooked up in parallel, so there are plenty of Amps available to run the board. I checked the power output from the Lipos and it is 11.37 volts (they are near storage level charge).
I have a USB shield with a bluetooth dongle attached to the Mega. When I run the code with my computer attached via USB, the code runs fine and the PS3 controller I use to operate the droid will connect and work properly. However, when I unplug the computer and power up the board via the droids lipo battery supply, the controller will not connect (I suspect the Arduino does not boot properly) until I do a hardware reset on the Arduino, then everything works fine.
Someone suggested I might have weird ground loop. So, I unplugged all of the wires that were connected to the Arduino leaving only the USB host shield, the Bluetooth dongle, and the power barrel plug connected to the Arduino. No luck.
I have tried using another Mega 2560 with the same USB shield and dongle. Same results. So, I put a Mega ADK (with built in USB) into the droid and have the same problem. Therefore, I don't think I have a bad board since I am getting the same results from three different boards. Since there are literally no other wires connected, I think I have eliminated weird/wrong wiring.
Does anyone have any idea what's going on with this?
Thanks,
Tim