Door Sensors for your Home

Home automation projects have become a creative outlet for tech enthusiasts and homeowners seeking to streamline and customize their living spaces. One integral aspect of such projects is the creation of DIY door sensors. These sensors not only add a layer of security but also serve as triggers for various automated actions. In this guide, we’ll explore the process of building DIY door sensors to elevate your home automation endeavors.

Understanding the Basics of DIY Door Sensors

Before delving into the construction process, it’s important to understand the fundamental components and functionality of a DIY door sensor. A door sensor usually consists of two parts: a magnet and a sensor. When the door is closed, the magnet and sensor are in close proximity, allowing the sensor to detect the magnetic field. When the door is opened, the magnet moves away from the sensor, triggering an event.

Materials You’ll Need

To build your DIY door sensors, you’ll require a few basic components that are readily available at electronics stores or online retailers. Here’s a list of what you’ll need:

  1. Reed Switches: These magnetic switches consist of two metal contacts that are brought together by a magnetic field. When the field is disrupted, the contacts open, triggering the sensor.
  2. Magnets: Neodymium magnets are commonly used for this purpose due to their strong magnetic field. They’re available in various shapes and sizes.
  3. Enclosures: Small plastic or metal enclosures will protect the components and ensure longevity.
  4. Wires: Thin insulated wires will connect the reed switch to the rest of your home automation setup.
  5. Resistors (Optional): Depending on your chosen microcontroller or platform, you might need resistors to protect the input pins.
  6. Microcontroller or Home Automation Platform: An Arduino, Raspberry Pi, or other microcontroller can be used to read the sensor’s state and trigger actions.

Step-by-Step Guide

Step 1: Assembling the Reed Switch

  1. Attach the reed switch to the doorframe using double-sided adhesive tape or screws. Position it so that when the door is closed, the magnet is within close proximity to the switch.
  2. Attach the magnet to the door itself, ensuring that it aligns with the reed switch when the door is closed.

Step 2: Wiring the Reed Switch

  1. Connect one contact of the reed switch to a digital input pin on your chosen microcontroller.
  2. Connect the other contact of the reed switch to the ground (GND) pin on the microcontroller.
  3. If required, use a pull-up or pull-down resistor between the digital input pin and the power source (VCC) to ensure stable readings.

Step 3: Programming

  1. Write or upload the code to your microcontroller. The code will read the state of the digital input pin connected to the reed switch.
  2. Depending on whether the switch is open (door open) or closed (door closed), you can trigger various actions, such as sending notifications, turning on lights, or adjusting your smart thermostat.

Step 4: Testing and Calibration

  1. Close the door and ensure that the reed switch is in proximity to the magnet.
  2. Monitor the sensor’s readings using the microcontroller’s software. Confirm that the sensor reports the correct state when the door is closed.
  3. Open the door and ensure that the reed switch and magnet move away from each other. The sensor should now report the door as open.

Step 5: Enclosure and Installation

  1. Place the reed switch, wires, and any additional components inside the chosen enclosure.
  2. Seal the enclosure to protect the components from dust and moisture.
  3. Attach the enclosure to the doorframe and door using adhesive tape, screws, or other appropriate methods.

Step 6: Integration with Home Automation

  1. Integrate your DIY door sensors into your chosen home automation platform or software. This might involve configuring rules, scenes, or scripts based on the sensor’s status.
  2. Test the integration by opening and closing the door and observing the associated actions.

Safety Precautions and Tips

  • When working with electronics, ensure safety by disconnecting power sources before making any connections.
  • Double-check your connections and wiring to avoid short circuits or incorrect readings.
  • If using a microcontroller like Arduino or Raspberry Pi, make sure to understand the pin configurations and required voltage levels.


Building DIY door sensors for your home automation project can be both rewarding and practical. These sensors not only enhance the security of your home but also provide triggers for a wide range of automated actions. By understanding the basic components, assembling the sensor, programming your microcontroller, and integrating it into your home automation system, you’ll be well on your way to creating a customized and intelligent living space. The DIY approach empowers you to tailor the sensor to your specific needs, making it an essential component of your smart home setup.

By andrew

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