Power supply change change gps readings?

Question

I was powering a GPS Sensor from the 3v3 pin of a raspberry pi and my reading for my GPS sensor had some strange symbols in the mix, but when i switched to the 3v3 on the arduino, my reading came back to normal. This wasted several hours of my time.

Any idea why i would get weird readings when using a different power source?? (even though it is the same voltage)

Note: Both the raspberry pi and the arduino are getting their power form the USB that is connected to my PC.

Answer 1

The Pi can only supply ~50mA from 3.3V. This is unlikely to be enough to run GPS.

In addition USB can only supply 500mA. This is marginal at best, and below the recommended minimum for Pi.