Multiple Servos, separate power source

tigershark35

Hi. I want to run 3 servos off of a basic stamp 2 and want to provide separate power to the servos.· How do I ground this. When I hooked up the separate power to red and black leads and the white to the pin, nothing happened and then I realized that the pin didn't get to ground. Any help is appreciated. I want to run 3 or 4 servos. I know that a separate servo server is an option, but I am not there yet. Just profing out my concept of what I want to do.

Thanks
JG

Mike Green

You have to have a common ground. That's really the only requirement. If you put the servos at some distance from the Stamp or have a lot of servos, you might develop noise problems, but that can be solved by filtering.

Mike Green

Just to be sure ... The ground has to include all the servos and the Stamp. The servo control signal (white I/O) is referenced to the Stamp's ground and the servo's ground. That's why the grounds have to be tied together.

tigershark35

Thanks Mike. They are right next to the stamp board right now. By common ground, should I just take the - of the battery back to Vss?· I didn't want to blow anything up. I am simply putting a pin high for each servo to learn how to program them, but figured that adding 3 servos would be a current drain on the BS2.

Jim

allanlane5

Yup, battery negative to board Vss. Make SURE you don't connect battery positive to board Vdd when you do this.

And the servo won't do anything unless the BS2 generates the servo control signal for it -- which is a PULSOUT from 500 to 2.5 mSec, repeated every 20 to 50 mSec.