Beam sensor or other switch needed for electric blind project

arduinomotorraspberry pisensor

I am designing a motorised blind (powered by a Raspberry Pi) and need a reliable way of detecting when the blind is fully "up" or "down".

I don't want to use a stepper motor, and rely on counts, as I want it to handle situations where the Pi crashes / power cycles.

The simplest way seems to be a switch or sensor to detect when the blind is up or down, and I think a beam sensor would be neatest. The sensor needs to work in the dark, as the blind should be able to function at night. (I plan to automate it so the blind closes when there is no-one in the room at night.)

Have looked on Adafruit, but can't see anything suitable. Does such a thing exist?

Best Answer

I would use a Proximity sensor of the type.

  1. A reflective IR sensor that detects if there is a object in front of it. It contains a infrared LED and a infrared light detector and the detector detects the reflections from the LED. At DigiKey you can find several hundreds of different versions DigiKey

  2. A Hall transistor (Detects magnetic fields) and attach a magnet to the blind.

Reference to proximity sensors Wikipedia

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