# parallax servo driver board



## ryanhailey (Jun 25, 2007)

Has anybody had any experience with the parallax servo board.
I am using it to drive three servos and it keeps bogging down.
I checked the voltage and there doesn't seem to be a drop.
Anybody else had this problem?


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## JonnyMac (Apr 5, 2007)

What are you using to power it? The PSC has been used in lots of big, multi-legged robots (that's where it started); make sure that you've got a power supply that can handle your servo loads.


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## ryanhailey (Jun 25, 2007)

I bought a 7.5vol 1000ma power supply from parallax.
I've put a voltage tester to it and it doesn't drop.
I'm wondering if it's because my usb is not 2.0.


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## halloweenguy (Dec 27, 2006)

shaggydo said:


> Has anybody had any experience with the parallax servo board.
> I am using it to drive three servos and it keeps bogging down.
> I checked the voltage and there doesn't seem to be a drop.
> Anybody else had this problem?


Yes...I use the board all the time with a 5 volt 3.75amp (3700ma) power supply that drives 6 servos. No problem here. This board does not care if its usb 2.0...This is only used to supply power to the board and fairly low speed communications.

I got a couple of questions...which servos are you using??? Are they mounted with everything connected or are they loose with nothing attached? Is anything binding? My gut feeling is like jonnymac suspected is that your power supply is underated.

FYI...You can smoke a Parallax USB servo controller with some of the Higher torque servo motors...The circuit board traces are not very wide.

here is what we use:
http://www.allelectronics.com/cgi-bin/item/PS-537/480/5VDC_3.7A_SWITCHING_POWER_SUPPLY_.html


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## Dr Morbius (Sep 21, 2004)

If you're using VSA, make sure the port baud rate is set at 38400. That's the speed Parallax likes.


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## ryanhailey (Jun 25, 2007)

I'm using the usb parallax board which runs @ a 2400 baud rate. The servos are standard parallax servos.


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## halloweenguy (Dec 27, 2006)

Dr Morbius is right on this one...It will run at 2400, but likes to be set @38400...just another check does it bogg down with just one or two servos?

another VSA tip is that vsa works better with wav files than mp3...I have seen many vsa routines that don't sync the jaw servo correctly unless you convert the file to wav format.


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## ryanhailey (Jun 25, 2007)

Every time I try to set it to 38400 it errors out.
It only boggs down when two servos are driving at the same time.


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## Dr Morbius (Sep 21, 2004)

You say it "errors out". What exactly does it say?


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## ryanhailey (Jun 25, 2007)

Don't mind me, I must have had a moment(or two) I just changed the baud rate to 38400 and what do you know perfecto.
You are awesome, I can't tell you how much I appreciate your help. Everything is working without a glitch thanks to you.


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