ir circuit help

[adrian120]

i've built a ir repeater circuit but am having problems with room light interfering with the photodiode. tried a photodiode with a daylight filter but no luck. i have come accross this band pass circuit and wondered if this would help.

 

[bloody-orc]

what light do you use in your room?

and you should try using ir sensing diode(IR sensor)

 

[adrian120]

just a standard light bulb no fluorescent light and a small amount of sunlight through a window. the circuit i built works fine when there is no light in the room. if i added this band pass filter to the circuit would it over come this problem?

 

[bloody-orc]

well thats the point daylight filter takes away all the other lights axept the standard bulbs light cause this also emittes heat and IR light and so your sensors see it

 

[audioguru]

Your bandpass filter will remove mains pulses from the heat of your incandescent bulbs and sunlight flickering, if the photodiode isn't overloaded by them and ordinary light.
But your bandpass filter circuit won't work because the transistor doesn't have a pullup resistor (10K) from its base to the positive power supply. The output of an LM393 is the collector of a grounded emitter NPN transistor, that can pull-down, not up.

 

[audioguru]

Forget about adding resistors to your bandpass filter. Now I see that the transistors that you show are actually part of the LM393.

 

[carlosthejackle2001]

Have a look at the HOLTEK range of chips.... The receiver chip wont allow an output until the correct code is received thus elimanating intereferance