General IR sensor question

How would I best go about determining what type of IR receiver would be best used with an existing IR beacon system that I have?

Basically, I have a certain brand IR beacon that is made to go on a race track and blast across the track (you put it "inside" the track and point it "out" so that it isn't blasting across but one spot on the track). Then that same company makes their own receivers that know how to see that beacon every time it's passed and show a lap time.

I want to build my own receiver that does the same thing. The problem is I know there are different type of IR emitters and receivers and don't know how to figure out what this one is emitting exactly. I may be able to take it apart and find part numbers and such, but if I can't, is there an easy-ish way?

I want to use this particular emitter instead of building my own (even though I'm quite sure building my own would be brain dead easy) because some tracks you go to already have this exact emitter living there permanently, so it's one less thing to deal with setting up (and often forgetting to retrieve at the end of a long day).



The main variable is the modulation frequency. To find this out simply hook up a IR photo diode and resistor in series across 5V. Then measure with an oscilloscope what frequency you are getting across the diode.

If you don’t have a photo diode you can do the same thing with an IR LED, but it needs to be up close & personal :slight_smile: = <1cm away from emitter.
See our blog post: Poor maker’s Infrared receiver #2

Sample code provided to calculate modulation frequency.

Also see another blog post: 'Silver bullet’ – the Oscilloscope Infrared Receiver

for an approach with an oscilloscope, similar to what @Mike suggested.

If you are looking to use a 3 pin IR receiver you can use the TSMP58000 and measure the modulated IR with your arduino. You will see some example code in the IRlib library. The author incorporated modulation frequency measurement in the latest relsease based on our original code provided with AnalysIR.

The other way would be to do the following.

  • IR receivers are typically 30,33,36,38,40 or 56kHZ. Just buy one of each and see which one gets you the longest range. That will ID which frequency it is.

Lets know how you get on.