Friday, November 20, 2015


I'm not very experienced with Circuits or Electricity.

I've read about it in the past and tried various little experiments but I have no particular experience beyond that.

In the past my emphasis had been to learn about how electricity worked.  Here I'd like to simply apply basic circuits to build remote-controlled mechanisms.  So the focus has changed.

With the Pi I have to now care about:

  • Controlling circuits.
  • Not blowing up the Pi as a result of wiring up a circuit to it.

My initial attempt was to try to control an SG90 Servo from the Pi.

I wired it up directly to the GPIO pins and the power, and the servo moved around a bit and then the whole Raspberry Pi rebooted.

I wasn't sure why because there were videos online of people doing exactly that with no issue.

I thought perhaps the Pi was being affected by the electrical noise and feedback of the motor, so I built a protection circuit to isolate the Pi.  This did not work.

After more thinking and searching, I concluded that perhaps the motor was exceeding the total power output of the wall adapter I was using.

After looking, I found that the adapter I was using produced 5V at 750mA.  I replaced it with one providing 5V at 1100mA, and the problem of rebooting has not come back again.

I will keep the protection circuit in place just for good measure.