Hello, on my robot I essentially have two sources of power. #1. The first is my 9-volt battery to the BS2. (+ pin 24, - pin 23) #2. my second is a power source for the motors. it uses four C batteries not directly connected to the stamp but with it's own system of circuitry. check thumbnail below. http://www.reconnsworld.com/motorcontrol.gif Now I plan to use a fairly simple three-pronged switch to turn the entire robot on and off. I believe that I will need to put the switch into the negative wire of the #1 power source ( cathode of 9-volt battery to pin 23). However, what about the second power source? Is there any way that I can tie both in to the same switch? On the other hand, I'm not quite sure if I need a switch for the second source. Perhaps all the transistors will take care of it. Any thoughts? I'm thinking that last paragraph is correct and that a second switch or a tie-in won't be necessary.