Pololu Robotics & Electronics
Menu
My account Comments or questions? About Pololu Contact Ordering information Distributors

Pololu Forum

Current sensor to turn a motor on/off

Hi All I am new to Pololu & Arduino, I am working on a new project that will run a total of Three motors and have purchased a Pololu Dual G2 High-Power Motor Driver 24v14 Shield & A-Star 32U4 Prime SV , I have successfully used one of the motor ports to run a motor and have one port left for another motor.

I want to sense the current of motor 1 to turn motor 2 on or off. The current running through motor 1 is 28Vdc and wanting to make motor two turn on when current drops below 1amp and turn off when current goes above 5amps. Motor 2 will be 12vdc 2amps

My project will have a total of 3 motors so I will require another driver anyway so my question is do I buy another driver for this part of the project or is there a better way to tackle this and I can use the second port of this driver for motor 3.

Hello.

You might be able to use the current sense feedback from your 24v14 shield to control your first two motors like you described. You can find more information about that on the product page, and in the “Control and feedback pins” section of the user’s guide.

You will need another driver for your third motor. Our G2 High-Power Motor Driver 24v13 uses a similar driver setup as the one on your board, but it is a single driver carrier. Alternatively, you might be able to use a less powerful driver depending on your motor’s specifications. You can view our full selection of brushed DC motor drivers here:

- Patrick

Hi Patrick,

Thank you for your reply, my concern is not soo much a powerful motor as how precise the current sensor is in the motor controller.

It is only going to drive a car windscreen washer bottle motor/pump.

I just need to read the output of motor 1 to give this info to motor 2.

Hello.

I think the current sense capability on your G2 High-Power Motor Driver Shield will be sufficiently accurate given what I know about your application. My recommendation would be to try test it out for yourself, and if you find it is not accurate enough, then you might consider using one of our more accurate standalone current sensors in series with your motor.

-Patrick

Thank you for your reply, I have followed the directions and connected the g2 pin “M1CS” to The A-Star board pin “A0”

Do you know of a Software template I can used to help Achieve

Monitor/ Check M1CS reading once every 40sec for 10 sec

Average out reading the CS over a 10 sec period

Motor 1 Current sense if below 1amp turn Motor 2 on for 10sec

If Current Sense value is above 2amps do nothing to Motor 2

Repeat

Unfortunately, I do not have any specific suggestions for a library or example program for something like that.

- Patrick