Let's Make Robots!

Help with IR sensors ~ TIL 38 & 81

I'm trying to set up a IR proximity sensor and these are the only ones available in my area. I have no datasheets or circuit diagrams.

Both are leds: TIL38 as transmitter; TIL81 as receiver 

How should  I connect them to my basic stamp?

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

The first link on a search for "TIL38" goes to the datasheetarchive.com, which shows a Texas Instruments sheet with a few basic parameters of several devices. Here's info to use fror determining resistor values for connection :



Thanx robologist.

 I'm only familiar with IR receivers that are of the 3-pin type (+ve, -ve, sig).


I'm thinking of  connecting the TIL38 in series with a resistor to a I/O, using the FREQOUT command. As for the TIL81, I'm unsure of the connection, +ve or -ve to the I/O?

The TIL-81 looks like an LED, correct? I believe the flat side, emitter, to ground, collecter to a 1k resistor to 5 volts, connection between collector and resistor to signal pin on micro.  Could use a larger resistor, 1k is just adequte on the specs.

It's finally working!!! The receiver must be connected in reverse-bias, just like what u described.


However, the detection is limited to about 1 cm, that is for proximity detection, without any resistot connected to the emitter. Connected to a 220 ohms resistor, the range is only about 2 mm.