Wanting to build an IR trip wire.

Discussion in 'General Electronics Chat' started by Tactical Viking, May 13, 2015.

  1. Farley

    New Member

    Jul 9, 2015
    Thanks, i should have clarified, i have a very limited understanding of circuits and how they work. Hopefully i wont be to frustrating with novice questions.
    I came across this site somehow by Googling something to do with tripwire and garage door sensors.

    So far from what i see in that post is that i should connect the wires of the sending unit and the receiving unit and feed the power to on of the splices BUT use a 51 Ohm resistor inline between the power supply and that splice.

    I'm lost past that( if i am even correct) , my question then would be:
    How to i use this setup to send power TO a solenoid in a sprinkler valve( to open it) for a period of say 5 -10 seconds and then after that period of time, turn the power off( closing it).
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    If you start with just the power supply (6Vdc wall-wart), the 51 Ohm resistor, and the two sensor units, you should be able to tell from the LEDs that the units are functional.

    To switch on your solenoid while the beam is broken, you will have to add the 555 timer chip, the relay, and all the rest of the parts in the schematic. To put an upper bound (reset after 10sec), you would have to add a second timer to shut the solenoid off if the beam remains broken...
  3. Farley

    New Member

    Jul 9, 2015
    I appreciate your responses, may look into this when i get a bit more time.
    Thanks again