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Topic: Problem of using an array of TSSP4038 IR sensors (Read 482 times) previous topic - next topic

kenwood120s

On the subject of the IR leds, I may have missed it, but how is OP producing the 38kHz carrier?

Oh ok nvm I saw it's some Nick Gammon voodoo in setup.

I'm wondering why you're using a carrier at all: what's wrong with an ir led which is just solid on when it's unbroken, sensed by a simple photodiode?

That said, and given you're thinking carrier already, would it be worth exploring modulating the 6 outputs uniquely so that each sensor is only reacting to its own transmitter. Then they can all be on all the time. (That's an off the top of my head thought. It won't be difficult to modulate the signal, but I'm not sure how big a deal it will be to demodulate it at the receiver.)

[gumby]I've got my head stuck in the cupboard[/gumby]

squaresun

I'm wondering why you're using a carrier at all: what's wrong with an ir led which is just solid on when it's unbroken, sensed by a simple photodiode?


Actually I've never thought about that. So what you mean is when I triggering them one by one then sensed by a simple photodiode would work. Did I get it right?

That said, and given you're thinking carrier already, would it be worth exploring modulating the 6 outputs uniquely so that each sensor is only reacting to its own transmitter. Then they can all be on all the time. (That's an off the top of my head thought. It won't be difficult to modulate the signal, but I'm not sure how big a deal it will be to demodulate it at the receiver.)


It seems quite tricky but I will try to look into it. Also, is it work with photodiode? Anyway, thanks for the reply.

kenwood120s

Well I've used a simple on/off ir led read by a simple ir photo diode, with no carrier required, as a break beam a couple of times with no problem.

More than that I can't say, I'm afraid.


[gumby]I've got my head stuck in the cupboard[/gumby]

Wawa

So I should look for an Arduino which has at least six output pin since each LED should connect to one output pin?
How about the sensors, each of them should connect to one pin of Arduino and also six pin is needed, right?
Yes, but most Arduinos have more tha 12 pins available.

Try to get one set working first.
The tone command could be ok for testing.
Leo..

Wawa

I'm wondering why you're using a carrier at all: what's wrong with an ir led which is just solid on when it's unbroken, sensed by a simple photodiode?
Ambient light could be a big problem with a 1meter gate.
Modulated IR receivers ignore static natural light and mains frequency modulated light.

It won't be difficult to modulate the signal, but I'm not sure how big a deal it will be to demodulate it at the receiver.)
3-pin IR receivers are so much more than a photo diode.
diode>amplifier>agc>demodulator>driver>voltage regulator, all in one.
Leo..

kenwood120s

Ambient light.
Leo..
Ok, and ambient light is very unlikely to trigger the 38kHz receiver with consistent, accidental 38kHz bursts.

[gumby]I've got my head stuck in the cupboard[/gumby]

squaresun

Yes, but most Arduinos have more tha 12 pins available.

Try to get one set working first.
The tone command could be ok for testing.
Leo..
Ok, I'll try that. Thanks for the advice. :)

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