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Pir sensor

  1. Feb 3, 2009 #1
    Hi friends,
    I need your help about a subject in my mind for a few months.
    This will be a project for a course. I want to make a device which controls the lights in the room. I do not know if anybody made this before or not. Also this thing will be useful for homes. You do not need to turn on the lights when entering a room everytime. I am thinking also this can be embedded in to the ceiling next to the lamp so need to dig into sidewalls for switch installation and cable.

    This device will do the following jobs:

    1- When a person enters the room, it will turn the lights on. (If it is dark of course, a LDR may hep I do not know??)
    2- When the people stays (it doesn't matter how many minutes he will stay in the room. It can be 2 minutes till 8 hours(when sleeping for example), it will turn the lights on and when the person leaves the room it will turn off afterwards) (Not like usual PIR sensors which has a adjustable delay) This thing need to detect if the person is sleeping or doing something. If sleeping it will turn the lights off. If he is doing something, for example watching TV, it will stay open.
    3- I want to install this in behalf of usual switches. So this setup must not be big. (mostly 3"*3") dimension.

    I found a sensor with a computer board in the following address.


    I need your advices on how it can be done. Thanks for the support...
  2. jcsd
  3. Feb 6, 2009 #2
    Yes, this has been done many times before. Many many companies produce products such as these. In fact, I just walked into a room of one of our clients recently and was surprise to see the lights go on. A few examples:



    How it can be done, simple!:
    1. sensor-could be a motion sensor (often using IR), a light sensor (to dime the light based on ambient light from windows for higher efficiency lighting), proximity sensor or any other sensor depending on your application.
    2. light- thermal bulb, flourecence, LED, ETC.
    3. circuit-could be hardwired, timer circuit, MCU, PLC, DCS, etc, etc,etc,

    What else you need to know?
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