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Servo Control — Parallax Forums

Servo Control

Scott PortocarreroScott Portocarrero Posts: 72
edited 2009-07-07 04:38 in BASIC Stamp
I am new to the Basic Stamp and loving it. I was fiddling around with the PingServoCenter.bs2 just trying to get something to do something. Everything worked but it seemed as if the was no oompfh behind the servo movement. It was really slow with absolutely no torque. I am using a brand new 9 volt battery for the Board of Education and the servo. Heeeeeeeeelllllllllllllppppppp! Do I need to add another 5 volt power source for the servo????

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2009-07-07 04:38
    9V batteries have no ummph. Specifically, they have limited current capacity (mAh - milliAmp hours) and relatively high internal resistance so their peak current output is low. If you're curious, do a web search for "9V battery capacity" (data.energizer.com/PDFs/522.pdf).

    Servos draw a lot of current at peak although the Board of Education's regulator can marginally keep up.

    Best way to power a Board of Education and one or more servos is to use a 6V to 7.5V supply. Four AA alkaline cells would work. If you're using rechargables, you need five or six AA NiMH cells. Servos are happier at the lower voltage (6V), so I'd recommend five AA (2300 to 2500 mAh) NiMH cells in series. Run the servos off the unregulated supply. They'll be fine as long as the voltage is 7.2V or less
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