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Topic: Help troubleshooting an IR Breakbeam circuit (Read 146 times) previous topic - next topic

abasel

Apr 16, 2019, 09:47 am Last Edit: Apr 16, 2019, 09:48 am by abasel
This is my first attempt at what for myself,  I would call a more advanced circuit (i.e. given experience so far :) ).

I have tried copying the following design: https://circuitdigest.com/electronic-circuits/ir-transmitter-and-receiver-circuit.

When I switch it on the LED flashes on and the goes off. After a while LED flickers on for a short period and then goes off.  This then continues like this intermittently. If I put an obstruction between the IR LED and receiver while the LED is shining, the LED goes off indicating that the IR Receiver and IR LED are working.

The video show what I mean. It is not easy to see the LED light up on switch on but the rest can be seen from about 35 seconds onward: https://www.youtube.com/watch?v=v6f-JRoWM4Q

Could this simply be a cold joint issue on the breadboard or should I experiment with capacitors?

As I finish writing this I realise that both circuits are being powered from the same 5.5V supply; could this be the problem?




Grumpy_Mike

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As I finish writing this I realise that both circuits are being powered from the same 5.5V supply; could this be the problem?
No.
The IR receiver is really a crap circuit drawn by a total idiot.

The chip itself is not designed to be used as a barrier detector but as a way of sending data. Go giving it a continuous burst of modulated IR will at first work but soon stop working.

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After a while LED flickers on for a short period and then goes off
Which is exactly what I would expect from that receiver chip.

wvmarle

As I finish writing this I realise that both circuits are being powered from the same 5.5V supply; could this be the problem?
Sure? One circuit tells you're using a 9V supply, the other 5V. That implies two different power sources, neither at 5.5V.

And that BC557 is drawn upside-down.

Please only post schematics that match YOUR ACTUAL circuit, not something "that is similar" or "based upon which" or so. We reply based on what you tell us. Provide wrong info, and you get wrong advice. Iow: garbage in, garbage out.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

abasel

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drawn by a total idiot
doesn't really add value to the discussion nor is it in keeping with the spirit of most public forums, unless the Arduino forum encourages belittling of others.

As for as the other comments goes, thanks for the input and direction :)

Grumpy_Mike

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doesn't really add value to the discussion
I am sorry I thought you might want to know this seeing as you can not make this judgement yourself.
Would you prefer it if I said the person who drew this was differently correct?

Paul__B

I can't see anything in the datasheet suggesting it has a high-pass filter function.  It shows a bandpass filter for the specified frequency, 38 kHz in this case, but no low-pass filter.

It does show an AGC function which may cause the behaviour indicated.

Grumpy_Mike

#6
Apr 17, 2019, 06:16 pm Last Edit: Apr 17, 2019, 06:17 pm by Grumpy_Mike
I can't see anything in the datasheet suggesting it has a high-pass filter function.  It shows a bandpass filter for the specified frequency, 38 kHz in this case, but no low-pass filter.

It does show an AGC function which may cause the behaviour indicated.
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Suitable burst length ≥10 cycles/burst
Also look at the graphs.
I speak from experience of using these things.

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