Let's Make Robots!

Brushed electric motor interfere with GPS?

On my AGV, I am losing GPS updates when I am in motion, or to be more specific, when I turn the back wheels with the big brushed motor. It is on an Arduino and I know about a potential soft serial and servo library issue, but it doesn't happen if I only turn the steering servo.

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This invalidates some of what I thought I knew. I had another GPS module come in the mail; I needed another one of those cheap Pharos GPS modules that I like so much to match ones in a couple of other units. Anyway, it comes as a USB GPS and I crack it open and solder to the TTL leads. But before I did that, I dropped it in the project box on the AGV right next to the other one, waited until it started pumping data, then powered on the AGV and sent it commands to fire up the motor and data kept right on pumping in. So it isn't the GPS after all (or at least not its capability to receive from sattelites and transmit on serial line); it is serial data being read being read on the Fio that has the problem. I think...

Anyway, I am still going to do the power conditioning caps and twist the motor leads. I di try another test where I continued to power the system with the BEC but had the ESC PWM line disconnected. The reason I did that is that there was a problem with using newsoftserial and servo libraries together and I had to revert to using servo2 to resolve it. So I wanted to make sure there wasn't still some software issue. there wasn't. Hopefully cleaning up pwer from the BEC will do the trick; I really don't want to add an additional voltage regulator if I don't have to.

 

A big (1000 uF) cap from BEC power to ground fixed it!