Infrared receiver TSOP 1736

[Wollo]

I have to demonstrate simple infrared transmission/reception to
learners. I can get hold of the tsop1736 receiver, but i am not sure
how to use it. Do i need to use the carrier signal, 36 Khz ?
Can i simply send a square wave with a 555 and an IR transmitter,
or is it more complicated than that ?

 

[Nigel Goodwin]

A simple carrier will make it's output go low - but it's not designed for operation with a simple carrier, and the AGC will tend to reduce the gain a lot.

Best to use two 555's, one at 36KHz gated on and off by one at a couple of Hz - use an LED on the output of the TSOP, and you will see it flash from the IR. Add a second LED on the transmitter slow 555, and you can demonstrate the relationship between the two flashing LED's.

 

[Wollo]

Ah, thanks. So the carrier keeps it kind of alive ?
I'm gonna experiment with it a bit.

 

[Wollo]

Please explain some more on the agc.

 

[audioguru]

The datasheet explains how the Automatic-Gain-Control (AGC) reduces the gain if there is DC IR from sunlight or continuous 36kHz IR pulses from fluorescent lamps with electronic ballasts. It explains that bursts of pulses are required to keep it at its most sensitive gain. It lists the recommended number of pulses in each burst and the amount of time for each pause between bursts.