Using DC motors

[lukevanoort]

Originally Posted by Guy_E

I wish I could use a victor, but my motors are 6-8V DC .

The Victor 884 is rated for 6-15V.

[Guy_E]

I think a victor is a little too big for my robot.

[Culvan Van Li]

Another thing to be aware of is the difference in PWM (pulse width modulated) signals. The VEX motor ports output a PWM signal that has a 1-2ms pulse every 18ms (11% - 22% duty cycle). This is the same style that is used for remote control servos. The Victor88X controllers are designed to take this type of signal.

If you design your own circuit using a L293 (or similar part) you will probably need to generate PWM signals that cover the entire sepectrum of duty cycles (0% to 100%) because you will probably be driving a transistor to drive the motor directly.

I'd also recommend you look into the HB-25 from Parallax. It functions like the Victor controllers but costs about 1/3 as much. It's a little bit smaller too. I'm currently using these with my VEX controller for cordless drills.

Andy