smoke detector circuit

Discussion in 'The Projects Forum' started by dobsie, Apr 11, 2011.

  1. dobsie

    Thread Starter New Member

    Apr 11, 2011
    hi everyone,i'm building a smoke detector project using a light source and an LDR.can someone pls help me with this project and also if there are better ways to build this detector,pls let me know. thank you.
  2. DickCappels


    Aug 21, 2008
    Is this for use as safety equipment or just for educational purposes?
  3. matty204359


    Apr 6, 2011
    My self i wouldn't trust a home made digital alarm clock to wake me up in time for work let alone a home made smoke detector. For the OPs safety I hope this is for educational purposes.
  4. retched

    AAC Fanatic!

    Dec 5, 2009

    Me too!

    If I built a smoke detector, it probably would not go off until the firemen were hosing it with water. ;)
  5. PerunaPete

    New Member

    Mar 17, 2011
    As long as you're looking into this for recreational purposes, you might start with an LED and a photo-transistor, or similar arrangement (you're going to need some sort of emitter and detector). The detector is going to be the tricky part, you're going to need some sort of comparator to distinguish the smoke signal(hurr) from the normal output of the emitter.

    I once made a simple circuit to send analog audio over a laser beam, using a photo-transistor as a detector. I found out pretty quick that smoke or vapor (such as dry ice used to show the laser beams) essentially puts a lot of noise in the signal.
  6. dobsie

    Thread Starter New Member

    Apr 11, 2011
    thanks alot for ur posts. yes,its for educational purposes but u guys make it look like a home made smoke detector can never be effective.if thats true that wats d purposes of all d educational projects if the cant be used i real life situations. and back to my question,is there any other way to build a smoke sensor without using LDR.i need a more sensitive component.can anybody pls suggest one to me?