How to make a motor go backwards.

I am using this board as a motor controller and I need to make the motor also go backwards as well as forwards.
I have been able to make it go forwards, but that's it. I thought that if I reversed the signals to J1 it would do the trick but no.

Your only option is to swap the motor leads. That module is just an on/off switch.

Post a link to specification of your board not just a picture. But you need an H-bridge to reverse a DC motor under control and that definitely doesn't look like one.

Steve

That module is just an on/off switch.

From the input labels and text it appears to be able to accepts a PWM signal to control speed but not direction of the motor. It would be possible to reverse the output using a DPDT relay but overall an H bridge would be a better solution

It appears that the pictured module is this basic circuit, with two MOSFETS in parallel and added LED/resistor.

Check the underside of the board for the inductive kick diode though, otherwise it may not work for long.

hextejas:
I thought that if I reversed the signals to J1 it would do the trick but no.

That is an unbelievably bad idea! :cold_sweat:

Fortunately, VGS is rated at +/- 20 V for this device though the LED might complain.

Suppose i had 2 of them and essentially did a swap as suggested but either one or the other would be active under control of an Arduino.
Would that work ?
It seems like it might.

Thanks

hextejas:
Suppose i had 2 of them and essentially did a swap as suggested but either one or the other would be active under control of an Arduino.

Do an image search for H-bridge. Although you'll see a hundred variations, one thing they all have in common is that there are four switches. To reverse the motor you need to reverse the voltage polarity and the switches, working in pairs, gives you this.

Here's another way to look at controlling your motor in both directions. Use a DPDT relay, or two SPDT relays controlled together, and a N-MOSFET (or NPN transistor) for speed control.


The Motor leads connect to the Common of the Relays, and + and - are switched back and for between the leads, which is also the function of an H-bridge chip.

Back to my original motor controller, how do I use an Arduino to turn it on or off ? Right now I have +5v going directly to the PWM+ post. It seems that under arduino control, I could vary that from 0v to +5v.
I will have to give that a try and see what happens.

hextejas:
Back to my original motor controller, how do I use an Arduino to turn it on or off ? Right now I have +5v going directly to the PWM+ post. It seems that under arduino control, I could vary that from 0v to +5v.
I will have to give that a try and see what happens.

The clue is in the name of the input, ie PWM
Feed a PWM output from the Arduino into it and vary the PWM output using analogWrite() to vary the speed

hextejas:
Suppose i had 2 of them and essentially did a swap as suggested but either one or the other would be active under control of an Arduino.
Would that work ?

No, even if you had both a positive and a negative poser supply and you cannot use four to make an "H-bridge" either because the "ground" pin of the input is also the negative of the supply connection, :astonished: