Powering the servos separately

bxgirten

I think the 2 servos are sucking the juice from my 9V battery righteously. To keep from a brown-out condition, I'm thinking of separate power for the servos. Has anyone done this? If so, what's the bare minimum needed to power them? I guess I could introduce a 3300 uF capacitor into the equation but wasn't sure if this would be an adequate alternative.

Jon Williams

You could power them with a 4x1.5v battery pack to get 6v -- this will work well. Just be sure that the ground from the battery pack is connected to Vss (ground)·of the BASIC Stamp control circuit, otherwise the PULSOUT signal won't work.

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Jon Williams
Applications Engineer, Parallax

Post Edited (Jon Williams (Parallax)) : 7/29/2005 3:21:20 AM GMT

Brian Riley

bxgirten said...
I think the 2 servos are sucking the juice from my 9V battery righteously. To keep from a brown-out condition, I'm thinking of separate power for the servos. Has anyone done this? If so, what's the bare minimum needed to power them? I guess I could introduce a 3300 uF capacitor into the equation but wasn't sure if this would be an adequate alternative.

I thought the Parallax servos were 6 volts MAX. 9 volts would cook them. Or are you running them on Vdd ?

an alkaline nine volt transistor battery is about 800 mah, a set of AA' runs about 2700 mah. BIG difference. The bottom line is to look at the size, 4 AAs take up more space they have more capacity. 9v transistor batteries are made for low current long duration use.


Brian Riley, underhill center, vermont

bxgirten

Brian,

What I originally meant was that I was using the 9V battery to connect to Javelin's Vin. 5V regulated was coming out but the 2 servos (I swear) were draining the battery causing a brown out sooner that I planned.

I'm not using a J-Bot (or Boe Bot) board but a programming board instead. There is no AppModHeader so I was wondering if powering the servos separately would do the trick. Last night I connected a separate 9V. 9V positive to the serov's red wire and the negative to Vss. It appears that I'm free of the brown out but will probably introduce some capacitors to mimic the AppMod header. I'm not comfortable having the servos powered separately.