Power supply problem?

Other Hardware General Electronics
1

I have an Arduino Uno connected to a computer via USB cable - no other power cable. I've connected an RF receiver and an RF transmitter. Both work fine and I amble send and receive stuff.

Now I've connected an LCD shield. Now the transmitter does not work (receiver works). When I remove 5v & ground from the LCD shield (ie LCD shield loses power) all works again.

Just by itself the LCD shield works fine.

Am I looking at a power problem or shield causing interference or both?

I have an Orange Pi nearby and I could supply 5v & ground fom its gpio pins. Is this ok? (I don't want to fry my boards) Are there some caveats in this setup?
What if I add a 9v battery connection to Arduinos power connnction (ie. can I have both USB and power at the same time).

2

Some LCD shields draw too much current when you have a lot of other power hungry items such as RF boards connected.

You are on the right path by supplying some items with thier own power.
Just ensure there is a common ground between the items and the Arduino.

DON'T share the positive rail.

3

Make sure they are not sharing pins.