755 motor driver

I just bought a 755 heavy duty motor controller that I want to use to control an 18v cordless drill motor that will drive a powerfeed for my mini-mill. I was using a simple pwm controller kit I bought online to power it but it burned out when the mill hung up on a piece of steel I was machining (It was only rated to 3a or so). The function I need is very basic - motor powers the table to the right, and then back to the left. I want to control it with a rotary knob that moves the table in the direction I turn it and controls the speed of the motor.

I was going to buy one of your motor controllers but saw a post here that it was impossible to get bidirectional control with an analog input (I was going to use just a simple pot for the control knob). So I decided on just a motor driver which I’ll interface with…uh something. But what? I see it takes a pwm input and an input for direction. So my question is, what’s the simplest way to make this driver do the above? Is there a knob-type pwm device that I can hook up to it or do I have to interface an Arduino (or other mc) onto it? I want to avoid the micro-controller route to keep it as simple as possible.



Hi, Spike.

Unfortunately, the simplest way to accomplish what you are trying to do would be to use one of our motor controllers. Specifically, the Simple Motor Controller 18v15 has the same operating voltage range as the driver you got and can deliver approximately the same current, but it offers higher-level interfaces like USB, RC servo pulses, analog voltages, and serial commands. What made you think that our controllers are not capable of bidirectional control? (Can you link to the post?)

If you want to use that motor driver, you basically will need to implement the high-level interface yourself. For example, you could program your Arduino to read your analog voltage and generate the appropriate low-level signals to make the driver turn your motor at the appropriate speed.

- Ben

No biggie, I’ll start dustin’ off my Arduino programming notes and get this sucka goin’!

I see. The key part of that statement is the “and a digital direction line”. The way our analog control works on the Simple Motor Controllers is that the middle of the pot corresponds to neutral while turning it one way increases motor speed in one direction and turning it the other way increases motor speed in the other direction (the exact behavior can be configured). The poster of that other thread wanted a pot to control speed and a digital pin (a switch) to control direction, which is not an interface option for any of our controllers.

- Ben