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16. System Integration

  • Design and document the system integration for your final project

All the components in your project

  • Raspberry Pi
  • IR Receivers and IR Transmitters
  • Monitor or display
  • Flask server or frontend code
  • Node.js or MagicMirror² modules
  • Power supply

Hardware Connections

  • IR Transmitters (LEDs) → Raspberry Pi (via Resistors or Driver Board)

    • IR LEDs are placed along one sides of the mirror frame.
    • They emit invisible infrared light across the surface.
    • Each LED is powered through:
      • Seeed Xiao Esp32C3 3.3V
      • A current-limiting resistor

  • IR Receivers → Raspberry Pi GPIO Inputs

    • IR receivers are placed on the opposite sides of the mirror frame.
    • The IR beams go across the screen in an invisible “grid.”
    • When a finger breaks a beam:
      • The receiver’s signal changes from HIGH → LOW (or vice-versa)
      • This change is read by the Seeed Xiao Esp32C3 GPIO pins.

  • Touch Frame → Raspberry Pi

    • The combination of IR transmitters + IR receivers forms an IR touch matrix.
    • Each IR pair is connected to its own GPIO so the Pi can detect which beam is broken.

  • Monitor → Raspberry Pi HDMI

    • The HDMI cable carries the MagicMirror² interface.
    • The IR frame sits in front of the monitor.

Software Connections

  • GPIO Inputs → Python Touch-Detection Script
  • A Python program monitors all the receiver GPIO pins.

  • When a beam is broken:

    • The Magic Mirror turns on.
    • This gives an approximate “touch coordinate.”

  • Touch-Detection Script → Flask Server

    • When a touch is detected:
    • The Python script sends a request to the Flask server (for example: POST /touch with X/Y coordinates)
    • Flask receives the touch event.

  • Flask Server → MagicMirror² / System Actions

Packaging

For the frame I decided to 3D print. As you can see I have slots in the sides that are prefect fit for the mirror and screen.

Diagrams

Reflection

Reliability of the IR LED grid?

Currently the reliabilty isn’t as great as I would want it to be only because the IR LEDs pick up different lighing meaning every once in a while it could be triggered whena finger not there. Other than that it’s been working really well.

False positive/negatives with different lighting conditions?

As mentioned above there are some false results. The IR LEDs read based on the lighing. For example, in a dark room it will be hard to detect the finger because the amount of light will constantly be dark. However, if you bring it outsie, the sunlight can contain the infrare radiation triggering the sensors.

Latency

The sensors and processor need time to distinguish between the intended IR signals from the LEDs and background IR noise. Sudden changes in ambient light can temporarily overwhelm the sensors, causing the system to take longer to register a touch or incorrectly ignore it. For example, if someone turns on a lamp.

Last update: December 15, 2025