IR proximity sensor and timing circuit for activating solenoid

Discussion in 'The Projects Forum' started by dthomas, Feb 11, 2011.

  1. dthomas

    Thread Starter New Member

    Feb 1, 2011
    I am working on creating an automatic flushing toilet lever. The concept is simple but my electronics training dates back 20 years. Please bare with me if I come off ignorant. Let me start with my concept. An IR proximity sensor circuit activates a push solenoid that pushes a lever arm up. Sounds simple right? I have found plenty of circuit diagragms for the IR circuit. What I don't know how to do is incorporate a time delay circuit into the mix. This will be very similar to the automatic flushing devices in public restrooms. I would like the solenoid to actuate only after someone, who has been standing in front of the IR proximity sensor for 5 seconds or more, moves away from the sensor. The system will be powered by Lithium batteries. The solenoid will most likely require a 12VDC supply. Any expert help on the circuit design would be appreciated.