I bought these "motor speed controllers" from Ebay recently with the intention of controlling the speed and direction of a DC motor:


However when I hooked it up to my microcontroller and tried running the PWM code, it did not work. When I played around with the included switch, it seems like the board can make the motor drive from speed 0 to max speed, but not change direction, like controlling a fan!

Is it possible to use the linked circuit board to control directionality of the motor? I got confused with the terms "motor controller", "speed controller", etc, and fear that I may have just bought a dozen of these that I can't use because I need bidirectional control.


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    \$\begingroup\$ All indication is that you bought yourself a motor speed controller. You may want to contact the eBay seller to see if they offer a product that has a full H-Bridge on it so support motor direction changing. \$\endgroup\$ – Michael Karas Sep 15 '15 at 3:15

I would use an H-bridge to control the motors. It doesn't look like the controller purchased allows for different directions.

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    \$\begingroup\$ Thanks for the response. Do you think I could create my own driver circuit with the appropriate H-bridge component, or am I better off finding a pre-built solution? \$\endgroup\$ – JDS Sep 15 '15 at 17:49
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    \$\begingroup\$ @JDS full H-bridge drivers are avaialble from similiar ebay sellers for $2-4 \$\endgroup\$ – crasic Sep 15 '15 at 18:01
  • \$\begingroup\$ I'm looking, been finding some but not at $2-4 dollars lol. Got a link by any chance? :) \$\endgroup\$ – JDS Sep 15 '15 at 18:11
  • \$\begingroup\$ Keep in mind my application needs to be able to handle up to 20A \$\endgroup\$ – JDS Sep 15 '15 at 18:18

I can see two pair of terminals on that board (motor + and -) AND (power + and -), I think that board can't change the direction, but you can change the direction of rotation by changing the motor supply terminals. There are some capacitors there ,changing power supply might lead to burning of the capcitors (DANGER)better avoid this,

Try to give motor output terminal(from that board) alternatively to motor to change direction.(use component that can manage 20A). enter image description here

Relay connection:

NC to motor(-) connector of the board

NO to motor(+) connector of the board

The motor is fed by COM pin of both relay,

Now if relay-1 ON and relay-2 OFF , MOTOR will rotate in one direction

when relay-1 OFF and relay-2 ON, MOTOR will rotate in ANOTHER direction

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