Introduction: Monitoring of Two Garage Doors

In 2016 we moved to a new house, where the garage doors are located in a way you can’t see them from the main entrance of the house. So you can’t be sure if the doors are closed or open. For monitoring only, the former owners installed a press switch. But the circuit was completely driven with 230 volts, which I found too dangerous.

Because the garage doors were over 30 years old and one door was stuck very often, we decided to exchange both doors and change the monitoring.

We decided to get new garage doors from HÖRMANN, they are easy to get here in Germany and they have all the necessary features. You can use the built-in remote control with encrypted signal, external switches and you have a dry contact for other electrical circuits.

Step 1: The Circuit With an Arduino

As I already did a lot of experiments with Arduino and Raspberry, I decided to use Arduino for this project. Arduino has enough contacts and is very easy to use. Power is available in the garage, and for the Status LED on the side of the Garage (Step 0) there is only a very small hole necessary. I used an Arduino Nano, because it is very small and consumes only very little power.

For monitoring I attached finally 4 LEDs, one red status LED on the outside (Step 0) and three on the small circuit box in the garage (Step 2). On the box there a three, a green one if the left door is open, a yellow one if the right door is open and a red one shows the same status as the outside Status LED. You don’t need the three additional LEDs on the inside, but I wanted to see the different states. Each LED is on one pin on the Arduino Nano.

I attached a reed contact to each garage door (Step 3) contacted to pins of the Arduino (one for each door). (If you don’t know a reed contact: A reed contact stays open in normal mode and closes if a magnet comes in the near range. So you can put the electrical part on the fixed wall and you only have to put a magnet on the moving part (Step 3).)

Finally I attached a 5V power supply to the circuit, put it all into a small case and mounted it to the wall in the garage. This system works now really flawless and without errors for more than three years.

Step 2: The Control Box Is Working

On the left you can see the power connector, a 5V 500mA power supply is attached via 5.5/2.1mm connector plug.

In the middle is the Arduino Nano on a small circuit board, on the upper side (red and black) power connections for the Arduino. The two black wires on the lower left side are connected to common ground. The next green cables connects to reed contact left door, the yellow to right door. All red cables go to LEDs and have a resistor with 220 Ohm in between. From left to right they connect to Status LED outside, green LED, yellow LED, red LED.

On the right side you can see the connector to the external components. I used an old 6 pin audio connector I already had in my workshop. Connected to external components are common ground (black), left door reed contact (green), right door reed contact (yellow) and external status LED (red).

Step 3: Reed Contacts and Conclusion

For me the project is closed for now. In addition a lot of other things are possible: door opening and closing with RFID chips, a Bluetooth connector or NFC. Until now I didn’t necessitate one of these features, but they can be implemented very easily, there are a lot of pins available on the Arduino.

Step 4: The Code for Arduino