Outdoor Break Beam Sensor

Using Arduino Project Guidance
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Hi all, I’m relatively new to Arduino so I want to check the feasibility or ideas on how to approach a project. I’m thinking of making a dual cone timing system for track training such as running 30-40m. I’ve done some research and a IR break beam sensor seems like a good fit for the project. However I’m worried it won’t be accurate outside on a track. Are there any other ways to achieve this or ways to modify the IR sensor to ignore interference. Again since I’m quite new to Arduino I may not understand everything but I’d be eager to learn if you point me in the right place.

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You may want to look at using a Garage Door Break Beam sensor. Google will bring up a few dozen examples. I know mine is not sensitive to daylight including direct sunlight. Another option is a LASER light emitter and sensor but for track I would just start with trying a garage door sensor. Sets off the boat can be had for about $15 USD. The idea is the light beam is modulated and the detector demodulates the light beam. Typically about 40 KHz but that's unimportant.

Ron

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  • IR outside ? Look at a laser.
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Playing with that several years ago.
30-40m is relatively easy for a narrow-beam IR LED and 3-pin 38kHz receiver, even without optics. Stay away from lasers. Too hard to aim at that distance, and possibly dangerous.
Leo..

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@Wawa thank you that that sounds really promising I’ll definitely check that out. Just a few questions, are you suggesting I buy a separate IR LED and receiver and if so which are the best ones I should buy? Do I need a custom circuit to create and modulate the IR waves?

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Hi Ron that would definitely make my life a lot easier, you have specific places that sell cheap ones on a quick google search I can only see sensors at a minimum of £50.

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I suggest you start with a common IR LED and a 3-pin TSSP4038 (not TSOP) receiver.
When you got that working, then replace the IR LED with one with a beam of <10 degrees.
Below is a sketch to generate 38kHz for the LED with an Uno R3.
The LED should be driven with a 2-transistor constant current driver with ≤200mA peaks, for max range. This project has been done several times on this site. Try searching for beambreak, tripwire, etc in the search field on top of this page.
Leo..

const byte IR_LED = 11; // IR LED with 100ohm (minimum) CL resistor

void setup() {
  pinMode (IR_LED, OUTPUT);
  TCCR2A = _BV (COM2A0) | _BV(WGM21);
  TCCR2B = _BV (CS20);
  OCR2A =  209; // ~209 = 38kHz
}

void loop() {
}
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Yep , Damp or wet weather can absorb the signal from IR

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I agree, while it maybe difficult to align (could use a lens) it will definitely be the most repeatable.
I would design the driver to have the laser on for the absolute minimum period of time. Like 1 µS every 100 ms.

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The least expensive I saw were on Amazon. Then too I am here in the US so not sure what's available on your side of the pond. :frowning:

Ron