pwmpal vs h-bridge with javelin controlled dc moters

TyreBiter

I am thinking of upgrading my jbot to a more robust mechanical platform using dc moters. I am afraid that I do not have any electronic or electrical training. I am a much better programmer.

To cut to the chase, I have been trying to figure out what dc motor controller(s) I will need to make the transition from jbot to dc-moter based autonomous bot. I am planning to use multiple javelin(s)/ basic stamp 2(s) controllers on the next bot as well. I am using a Parallax Servo Controller (Serial) to controll my servo based wheels now on the jbot and am very happy with the interface and control mechanisms in it. I have noticed that there is no mention of the pwmpal in the javelin forum and very little on the h-bridge controllers either. The packaging of the pwmpal has a very low impact in boe board resources.

Can the pwmpal directly drive a couple of dc-motors by way of the javelin?

Do I need additional circuitry?

Is the javelin an appropriate controler for the pwmpal?

What are the trade-offs between pwmpal and h-bridge controllers?

I would realy like to see some circuits for either configuration if anyone has any suggestions.

Thank for your help in advance...

AuburnSky

bulkhead

For DC motor control, an easier (though maybe more expensive solution) would be to get an RC speed control and control it using pwm. Speed controls range from $30-$60 for decent ones, check out www.towerhobbies.com.

I dont really understand what your saying about the pwmpal-if the javelin's max current output is around 100ma, the only way it could drive a motor would be for it to control a transtistor or simliar control wire to some other current-controlling circuit.

TyreBiter

Thank you for replying to a rather confused request.

While floundering around I came accross an article from Nuts&Volts at

http://www.parallaxinc.com/dl/docs/cols/nv/vol4/col/100.pdf

The article describes a circuit that contains the pwmpal, dc motor and a mosfet. What I gather from the article is that the pwm signal and mosfet are used to very the resistence in the circuit and change the voltage that the dc motor sees. I am sure that I am way off.... any way if you have the time to look at the article and comment on the usefulness of the design it would be much appreciated.

And thanks again for the response.

Regards

AuburnSky