powering servos

studiomagic

I'm using the BS2·to move two servos using PULSOUT command. I'm using a 9 volt battery plugged into it now, however the draw is killing smoothness! The servos operate at 4.8 volts each. When I slow the servo's down to move very slow·they are very jerky with both running at the same time.·If I run one servo in the command line, it is 80% better than having two. I went to the hobby shop and bought a 6 volt 1100ma battery to power just the servos. I'm using PIN 13 and 14 for the servos. I can't find a diagram showing me the right way to supply the 6 volt 1100ma power to the servo and keep the 9 volt for just the BS2. If anyone out there can email me I would appreciate it.·

Mike Green

It's very simple. All the ground connections (usually black) have to be connected together. The positive 6V goes to the servos' positive (red) leads. You leave the 9V connected as is to the BS2 board and you leave the servo control leads (usually white) connected as is.

9V batteries have very little current capacity. They're not very good at powering motors. They do ok powering a BS2 by itself.

studiomagic

Mike,

·I'm using the BS2 Board Of Eduaction Rev C. I have a jumper on the Vdd and I have the servo end plugged directly into the servo slots 13 and 14. How can I keep the end plugged in and wire it?

Thanks, Jim

Mike Green

The best thing to do is to set the jumper to power the servos from Vin and to use the 6V battery for Vin. When the BOE is part of a BOE-BOT, the whole thing (Stamp and 2 servos) is powered via Vin from a 6V alkaline battery pack and works fine that way. If you use 4 AA NiMH batteries instead of the alkalines, the voltage is really 4.8 which isn't enough for the Stamp's regulator to work properly. I assume that your battery pack is made up of 5 NiMH cells which would give 6V (5 x 1.2V).