Quantum phenomenon in running multiple servos

After I successfully run one single servo based upon sensor's signal, I simple assume the add up of voltage/current will work. However, this is totally wrong. Here I will share some trouble shooting experience. Most credit should go to John and Neil.

1. The signal from range finder freaks out when you use 1 big servo.

Solution: use other power source to power servo, such as 9V battery(this sometimes also do not work.....), adapters, instead of 5V pin on arduino.

2. Rule of Thumb : connect all ground termials (arduino, power source, servos) to one place.

I can not explain but this helps a lot.

3. If I notice this ahead, I will try servo controller (a customized version of arduino that has more pins for servo, but still you should separate power source)

This guy has some postings for running multiple servos: http://roborobert.com/2008/03/arduinos-servos-batteries-oh-my.html