Simple Object Detector

Discussion in 'General Electronics Chat' started by Abdullah90, May 15, 2011.

  1. Abdullah90

    Thread Starter New Member

    May 15, 2011
    1
    0
    Hi Friends!

    I want to make a project. My own project. My project is like this.
    This project is a letter detector. I will put this thing in the postbox. When a postmen insert the letter in the postbox, the LED outside the postbox will light/'on'. This LED will continously 'on' until the letter is taken.
    My postbox is located at the gate. So, the circuit must be all connected in/near that postbox.

    Please, someone give me the idea. Better if it is the cheapest and easy way.

    Thanks!
     
  2. cjdelphi

    New Member

    Mar 26, 2009
    272
    2
    is there a latch on the postbox? if so a reed switch would activate on the open/close of the post box, you could then have the light switch on until you hard reset it at the box to start over...

    you'd need a pretty bright LED for it to work in the daytime though, should look purty at night....
     
  3. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Sounds like a neat project but be prepared for the bomb squad to show up to investigate the suspicious device in your mailbox.

    Does your mailbox have a door to open, or just a slot through which the letters are deposited?
     
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,386
    1,605
    Personally I would make a light beam inside the mailbox so a letter or package would break the beam to sense mail. Depending on the mailbox it may take several beams to sense all mail.
     
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