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IR Emitter detector

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Wolfer14

New Member
I work in the audio and video (home automation) field and I’ve been plagued with troubleshooting faulty IR Emitter issues. The only way we could truly know if an IR Emitter was working was to use a cell camera. This works! But can be a real pain.
I found some planes on a web site on how to build an IR Detector. IR Detector I thought that these plans would be perfect for my application. I went ahead and build it. After it was built and working I started to test it in the field. Turns out that it isn’t all that it is cracked up to be.
It will give you feedback on any handheld remote if it’s within a foot or less (the closer the better) this is its strongest asset. It fails on the rest.
When I tested it with IR emitters. I started running into issues. The elan IR’s work but are very faint…you have to place the IR directly on the Fototransistor just to see the faint led flash. I cannot simply place the IR detector up the IR emitter that is on a component to see the visible light. I have to take off the emitter and flip it over place it directly on the detector just to see a faint flash. How come the TV or Component can see the flash inches away??? But not the detector??
Elan also makes an IR that has a Talk Back feature; this will emit a visible light to let you know that it’s working. These will not work at all with the IR detector…??? But a TV or component can see it??
Also found that some other IR emitter manufacturers don’t work???
So what I’m looking for is an IR detector that will act just like a component IR receiver.
So that if I put any manufacturers IR Emitter in front of the detector it will see it and give me a visible feedback, Talk back or not. I should be able to place the emitter within inches of the detector and it should give me a strong visible light.
Does anyone out there have a solution to my problem? If you do I would greatly appreciate your insight.
I am also a newbie when it comes to understanding circuits. Pls be gentle...Thx
 

mneary

New Member
Tis TSOP6238TR IR Receiver Module for Remote Controls (Vishay)-The Electronic Goldmine should receive IR transmissions. The following circuit should amplify the output so it can drive a reasonably bright LED.

Note that the TSOP6238's voltage is supposed to be 2.7 to 5.5V so the ideal supply is 3xAAA batteries, and 9V is definitely out. Any lower than 4V and the LED might not light (depending on color). If you use red, most would work on a 3V supply.
 

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audioguru

Well-Known Member
Most Helpful Member
I think the problem with the extremely simple IR detector is that many remote controls blast a very high current into their IR LRDs but the current is on for a very short duration for each pulse. The simple detector will light its LED for very short duration low current pulses which make its LED very dim.

The detector needs a peak detector circuit that charges a capacitor to the peak voltage of the pulses then slowly discharges while lighting its LED continuously.
 

HarveyH42

Banned
A hand-held oscilloscope works pretty well. Don't remember all the details, I did a lot of play back then, with my new toy, but it will pick up a weak signal. You can tell the pulses from the noise, probably do some measurements, but accuracy might be questionable. Never really use it to measure stuff, just to look at pulses and wave forms.
 
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