I have this project (see blueprint) where is one servo motor: Hitec HS-5985MG (http://www.servodatabase.com/servo/hitec/hs-5985mg). First I used one 9V battery to power the system up, but there was not enough juice to keep it running. It only worked properly for a few seconds. Then I bought a compact 12V/2A external power supply , but it seems to get Arduino to warm up and after a few second the system doesn’t work properly.
The system is as follows: When you move in front of IR proximity sensor the servo motor cycles around, when you go away from IR the servo stops. That simple. The on-off switch gets the led on and the system is ready to do what it is supposed to do. When OFF, the servo doesn’t move.
So, is the 2 amps too much? Should I get a smaller amps power supply?