The first step would be wiring up all the basic components (things you don’t have to build). You’re going to need:

  1. The adjustable power supply
  2. DC Buck converter
  3. Arduino
  4. The 25kg Servo
  5. 2 Sensors

Refer to the wiring diagram above.

Set the adjustable power supply to 7.5 volts. Seven volts is the minimum amount for the Arduino so 7.5 is enough, but not too much that we are wasting power. It’s also more than enough for the servo. It’s actually too much for the servo so we use the DC buck converter to lower the voltage to 5.8 volts for that component. When idle, the entire project consumes around 10 milliamps, so you don’t have to be concerned about your electric bill going up.

Use a breadboard when wiring it up for the first time.

Be careful working with the DC power supply. Don’t get shocked!

You’re going to need to cut the end of the power supply so you can attach the wires to the buck converter. Keep the plug end that’s cut off. You’ll need to connect that to the Arduino’s power jack. There are some pics above showing how I wired it to the perfboard.

After uploading the code through the Arduino Programming IDE test out all the components. The sensors should trigger the servo to turn 180 degrees. The code is written so that you must trigger the sensors in a specific order — ie. left to right or right to left depending on where you place the sensors. I did it that way to help avoid false triggering of the opener. Even though I did this, you sometimes will get false triggers when vacuuming near the sensors. No worries. The door doesn’t open with enough force to break anything.

Test it out! Later on, after installing everything you can tweak the sensitivity of the IR sensors. There is a little adjustment screw for that.

I would suggest using machine screws and nuts to attach the power and ground wires from the IR sensors. This way you can feed the wires underneath the cabinet and attach them inside the cabinet. You can also use this technique for attaching the power supply power and ground wires.

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