NE 555 IR Detector

[Gayan Soyza]

I built an IR detector through NE555.Because i needded to give a clean
pulse to a pic ic or a latch ic to drive a relay.

This cct works in any tv remote controller.

when u give an ir beam or when u press tv remote the led lit up and off after
a half a second delay.this uses a monstable state delay about closer to 0.5 s.

this circuit works well,but it has a problem.

when u switch on from the power switch it gives a signal (led will on).When u switch off even it gives a signal.this will effect the output relay to switch on/off without giving any IR beam.this must be prevent some how.

anyboby knows how to prevent this?

Hoping a reply from u guys.

 

[penoy_balut]

IR transmission is data modulated 40kHz for the receiver to distinguish which button is pressed, while your circuit activates on any received, you need microcontroller in your receiver to decode incoming IR, the easiest to decode are sony remote controls.

 

[justDIY]

IR transmission is data modulated 40kHz for the receiver to distinguish which button is pressed, while your circuit activates on any received, you need microcontroller in your receiver to decode incoming IR, the easiest to decode are sony remote controls.

the circuit is already using a demodulator IC, so it will be rejecting stray IR automaticly.

it looks like Gayan is having trouble with the circuit activating on powerup, even without an IR signal detected.

Gayan, do you have a scope handy? I suspect the IR decoder is glitching during powerup and powerdown ... but it looks like you already have a basic debounce in place (Resistor and capacitor) ... have you tried changing the value of the capacitor on pin 2?

 

[Gayan Soyza]

justDIY you Got my idea thats the problem I have.The circuit has a basic debounce.I must change the capacitor value and try......

Thankx DIY for the solu....

bye

 

[philba]

I would think a schmitt trigger instead of the 555 would be an easier approach. what are the advantages of the 555?