Need help with Infrared Emitter/Detector project

Community General Discussions
1

Hi all! Relatively new to building electronics, so I was looking to hopefully find some help in getting my project to work. It’s simply this: I have the Inex infrared emitter and 38khz receiver. I would like to set it up so that I basically have an infrared gate so that when something moves through the gate, I get a signal I can send to my transistor - a sort of simple pass-through switch - which in turn will send a signal to my computer where my program takes care of the rest of my project. Relatively simple, I would think, except that I really don’t know how to get this beam working.

  1. The infrared emitter board does have the mode to generate the 38khz frequency, but I’m not sure how to get this effect (ie. what voltages are necessary on the Vcc and signal)

  2. I’m not sure what level of power will be sent from the receiver on detect/non-detect or how to translate this to a simple off/on for my transistor.

If anyone has the tech specs for both the parts and/or any help/advice to get me further along, I would GREATLY appreciate it.

The links to each part here:

Infrared Emitter
Infrared 38khz Receiver

Please be as technical or as simple as you like - I’m not really sure if this is simple or much more difficult than I originally thought. Thanks in advance for any help!

2

Wow - Thanks! All this really helped… I’ll give some stuff a try and see how it goes.

3

:smiley:Hey,

You need to modulate that board via PWM. Look around online you’ll find lots of different ways to modulate that LED. It actually says how in the product description:

Usually an LED only has 2 leads (Vcc and Gnd). That one has 3 because it is designed for the Inex robot kits. You can see the pinout in the bottom left of this image taken from a Kit description:

The receiver has 3 pins (Power, ground and signal). That signal pin is what will be set off. The usual scheme is HIGH (5V) or LOW (0V) depending on if sees the modulated light or not.

You can then catch this state change using a Phidgets Interface Kit (I have an 8/8/8) via USB and program in .NET.

Once you have that working with the receiver you can use a black straw or shrink tubing to narrow the IR beam. This will be your invisible tripwire :smiley:

Well invisible to the naked eye :sunglasses: