DIY MOSFET Motor Controller

Written by: roboguru

Picture of DIY MOSFET Motor Controller

This is a simple to build motor controller. It is handy for many projects using a motor controlled by a micro-controller. It can be used as an Electronic Speed Controller (ESC) and has forward and reverse control. It can be used in robotics, remote control projects, portable vehicles and most things motorized. It also uses very little parts. All of this is made into a tiny package to fit in your DIY projects.

This circuit is based off of a Driving Bigger Loads circuit in one of my books. That circuit only used one MOSFET and a diode. It is meant for a micro-controller to control a motors speed. To be able to go in reverse I just added a DPDT relay and another MOSFET, diode pair to control the polarity switch. I hope you enjoy this instructable.

Step 1: Tools and Materials

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This Motor driver is very simple. Because of it's simplicity it uses very little parts.

Materials:

  • Perfboard - use any perfboard that you have or like
  • Thin Wire - I used a 24 gauge solid core wire
  • 2x Power MOSFETS - I used the IRF510 but any equivalent such as the NTE2382 will do
  • DPDT 30v Relay - the one in the pincture above is incorrect
  • 2x Rectifier Diodes
  • Pin Strip - use a kind that you can snap off little increments from

Tools:

  • Soldering Iron + Solder
  • Hot Glue Gun + Hot Glue
  • Wire strippers/cutters - make sure they can be used as pliers
  • DREMEL - use any tool you like for cutting the perfboard

Step 2: Assemble the Pieces

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Place all of the components onto the perfboard. Place them so that you can easily solder the circuit to the schematics diagram shown above and still fit neatly onto the board. For the pin strip just snap off a 2 pin increment and a 4 pin increment (You do not have to do the 2 pin increment if you wish to solder the motor directly to the circuit). Cut the 2 pin increment shorter on both sides and using you wire strippers bend the long end of your 4 pin increment at a 90 degree angle. If your wire strippers do not have this function just use an extra set of pliers.

Step 3: Solder the Components

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After placing all of the components onto the perfboard. Solder the circuit to the schematics diagram shown above. You can use any soldering iron and solder that you prefer. Use the part leads to connect two close leads and jumper wires to connect far ones. For the jumper wires use your wire strippers to cut and strip the ends of a small piece of wire. Use them to solder two distant leads together. For the perfboard I found the ones with copper work best for this compact circuit soldering but bare perfboard is cheaper. Also in this step you can also solder the motor strait to the board or use the 2 pin increment as I did. My finished circuit is shown above.

Step 4: Cut Out the Circuit

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For you to use this in small systems such and controllers or robotics the next thing to do is to cut out the circuit. I cut to the size of the circuit I made but you can cut it to any size that you want or for different functions. Just make sure that you keep the circuit functional. Cut the perfboard from the bottom so that you can cut below the control and power pins. Use the DREMEL or any small saw to cut it out. I found the DREMEL to be the easiest tool to cut the perfboard but use any means you please for doing the job. In the end make sure that the control and power pins are able to be pluged into a breadboard or other circuit.

Step 5: Tidy it Up

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Now just add the finishing touches and tidy it up. Shorten the remaining wires that stick out. Use the wire strippers to cut off the protruding wires. You can also use the pliers end of the wire strippers to bend the wire back and forth until it breaks off the end. Make sure not to break any solder joints using this method. After that plug in the hot glue gun. To make sure this circuit does not short circuit use the hot glue gun in a zigzag pattern to cover the circuit. The finished product should look like the image above. This should then keep the circuit from short circuiting and to further insulate and protect the circuit.

Step 6: Use it

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Now it is time to use your new motor controller. If you have designed and built it like I have than this should be easier and you can just follow the layout above. If you have placed your pieces differently or soldered the circuit together differently than just look at the schematics layout above. Either way make sure you look at the schematics diagram above.

Setup With a Micro-controller:

  • Plug or connect your motor to the motor pins on your motor controller.
  • Insert the motor controller into a breadboard.
  • Using two colored wires connect the Vin to your micro-controllers Vin pin And the GND to the GND pin.
  • Using two more colored wires connect the speed and reverse to two digital pins of your choice.
  • Now just program away.

Safety:

  • Make sure that you do not exceed 30 volts at Vin.
  • Do not mix up the pins.
  • If you decide to go over 15 volts connect the Vin and GND directly to the source and connect the Ground to the Micro-controllers GND.
  • When working with more power try attaching a heat sink to the MOSFETs.
  • Only use DC two wire motors.

Thank you for reading my instructable.

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