I'm trying to build a "trip wire" system with Arduino. I've got one working well with a laser and photoresistor, but the cost and narrow beam of the laser is not ideal, and I thought I'd try to do the same with infrared but I've had no success.
The receivers I've purchased detect stereo remotes, but not any of the emitters I've bought. I don't know why, and think it has something to do with frequency, but I'm unable to figure it out. Im hoping someone would be kind enough to recommend a set of emitters and receivers that would work together, and help me with voltages and whatever other info I would need.
I need the trip wire to extend across a driveway, and it will be used in daylight.
I don't have any technical data; however, garage doors and some ice makers in freezers use an infrared broken beam tech. Maybe you could research into that.
If your detectors detect IR remote signals, that suggests they're 38kHz detector/demodulators.
You could modulate your emitters using a simple 555 circuit.
I'm trying to build a "trip wire" system with Arduino. I've got one working well with a laser and photoresistor, but the cost and narrow beam of the laser is not ideal, and I thought I'd try to do the same with infrared but I've had no success.
The receivers I've purchased detect stereo remotes, but not any of the emitters I've bought. I don't know why, and think it has something to do with frequency, but I'm unable to figure it out. Im hoping someone would be kind enough to recommend a set of emitters and receivers that would work together, and help me with voltages and whatever other info I would need.
I need the trip wire to extend across a driveway, and it will be used in daylight.
I appreciate the help!
Robust commercial outdoor units are available and are not expensive, you may have seen them around car sales forecourts, these are able to work day and night you just feed 12v, the receiver gives out contacts N/O & N/C and can cover a narrow beam over 30 meters and I seem to remember some covering 100 meters.
I have made some but they need magnifying lenses to give a focal point, another way is to use a lazer beam but the receiver has to be shielded from ambient light. you can make up posts with mirrors deflecting the beam to crisscross an area using a circuit with a 741 and LDR etc.
AWOL:
If your detectors detect IR remote signals, that suggests they're 38kHz detector/demodulators.
You could modulate your emitters using a simple 555 circuit.
A typical IR receiver will reject a continuous 38KHz signal. Vishay part nos TSSP4038 and TSSP58038 are the only two that I'm aware of that won't.
A continuously energised led may not put out enough light to be detected.
Remotes work by putting out pulses at very high current. Levels, something like 50 times the max rated current of the led.
Continuous 50 x current would of course destroy it.
Boardburner2:
A continuously energised led may not put out enough light to be detected.
Remotes work by putting out pulses at very high current. Levels, something like 50 times the max rated current of the led.
10' distance with a generic 5mm, 20ma, IR LED (at 20ma) would handle it no problem. A white, 20ma LED would even handle that distance. If you use a stronger LED like a TSAL5100 (100ma continuous, 200ma peak) then it should easily cover the width of a two-car driveway, but I wouldn't expect it to be necessary to drive it at a full 100ma current.
