need help IR program...

karthickiw · Joined: 09 Aug 2007 Posts: 82 Location: TN, India

hi,

I need idea to transmitter the IR ray to 10 meter, this IR ray is detected by IR receiver at the end of 10 meter. When ray is cut to operate the relay this my application.

I using the PIC12F675 IC to produce the 3KHZ frequency and give to the IR transmitter, and receiver side is to read the 3KHZ signal. When IR receiver is read the 3KHZ freq signal in small distance, to increase the distance signal is goes to zero. Pls give some idea or any circuit....

by
karthic.E

mathewss · Joined: 07 Aug 2008 Posts: 17

It sounds like you want a light break alarm of sorts.

When the light beam no longer hits the light sensor a trigger happens..

What exactly does this have to do with 3hkz i dont understand what you are doing.

Re

newguy · Joined: 24 Jun 2004 Posts: 1908

It's standard operating procedure to modulate the IR lightbeam so that it can be clearly differentiated from essentially "DC" IR light sources such as sunlight, light bulbs, etc.

To boost the range you'll need to boost the IR led's drive current. If you tell us a bit more about your circuit (post a schematic if possible), we can do more to help.

Rohit de Sa · Joined: 09 Nov 2007 Posts: 282 Location: India

karthickiw, are you in India? If so you can purchase a cheap lazer pointer for less that INR25. You can modulate the light from the lazer pointer, and send it to a photo transistor.

As mentioned by newguy, you can also use high power IR LEDS with lenses, and maybe a TSOP at the receiving end.

Is there any reason for using 3kHz? Most of the TSOPs detect IR at a higher frequency (38kHz is commonly used).

Post a schematic; we'll try to help out.

Rohit