Laser pointer switch

Discussion in 'The Projects Forum' started by AdamPrulhiere, Nov 21, 2009.

  1. AdamPrulhiere

    Thread Starter New Member

    Nov 12, 2009
    I have a project where I need to make a switch that is activated with a laser pointer. I have a general idea on the schematic and design, but I am not sure what to use for the detection of the laser. Does anybody know a good component to use for this? I am looking for a component and its data sheet so i can design the opamp interface and get the initial design turned in. Thanks!
  2. BMorse

    AAC Fanatic!

    Sep 26, 2009
    a small solar cell such as the ones you find at Radio Shack, make good laser detectors....
  3. SgtWookie


    Jul 17, 2007
    Is the use of an opamp a requirement?

    Since this is a homework assignment, it really belongs in the Homework forum.

    However, a comparator is really what you need.

    A CdS light-sensitive resistor might provide what you need in the way of light sensing. It's slow to respond, but adequate with human movements.
  4. someonesdad

    Senior Member

    Jul 7, 2009
    A photodiode also can also work.

    You may want to consider some type of reflector too. You didn't say how far away the user will be, but it might be hard to hit a small spot on the wall across a room. Some reflective Mylar in a cone shape might help.
  5. hgmjr

    Retired Moderator

    Jan 28, 2005
    Can you confirm whether this is a homework assignment?

  6. AdamPrulhiere

    Thread Starter New Member

    Nov 12, 2009
    yes the opamp is required. I know that it would be real easy to do with a comparator but i need to include either an opamp interface or a 555 timer somewhere in it.