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Help with IR receiver

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axro

New Member
I'm messing around with an IR receiver that I took out of an old VCR. It looks like it may be a Vishay. The Datasheet I'm looking at is this:

http://www.datasheetcatalog.org/datasheets/90/301373_DS.pdf

It says supply current in 5mA. But if you look at the application circuit it doesn't show that you need any resistors at all. I'm going to plugging it into an Arduino. Do I need to limit the current to 5mA or do I plug it right into 5V+?
 

MikeMl

Well-Known Member
Most Helpful Member
You should just connect it to whatever voltage the spec sheet says it operates on. If you do, you should expect that it will naturally draw 5mA from that power supply.
 

axro

New Member
You should just connect it to whatever voltage the spec sheet says it operates on. If you do, you should expect that it will naturally draw 5mA from that power supply.
So when a datasheet says "Max Supply Current". That means how much it will use? Not how much to give it? Is that always what it means? What will it say if this is the max you can GIVE it. Forward Current?

It's absolutely critical that the supply is suitably decoupled, check my PIC IR tutorial hardware for an example.
I didn't decouple it yet. I'm hoping that's my problem. I have it connected to an arduino, the program I have running spits out the pulses out the serial port. But I can press the same remote button 5 times and get different pulses every time.
 

Nigel Goodwin

Super Moderator
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So when a datasheet says "Max Supply Current". That means how much it will use? Not how much to give it? Is that always what it means? What will it say if this is the max you can GIVE it. Forward Current?
It's the value it might use, not anything external.

I didn't decouple it yet. I'm hoping that's my problem. I have it connected to an arduino, the program I have running spits out the pulses out the serial port. But I can press the same remote button 5 times and get different pulses every time.
IR receiver IC's have absolutely massive gain, without correct decoupling they commonly oscillate.

But as you're trying to decode the incoming signal, and output data via the serial port, is your program working correctly?, and is it designed for the specific remote you're using?.
 

axro

New Member
It's the value it might use, not anything external.
Thats good to know. When I hear Max Supply Current, I think thats the max current you can supply it(like 20mA on an LED). But when they say Max Supply Voltage, that means the Max Voltage you can actually GIVE the component.....correct?

But as you're trying to decode the incoming signal, and output data via the serial port, is your program working correctly?, and is it designed for the specific remote you're using?.
I think it is working correctly. It's not designed for my specific remote. It's supposed to help me detect the protocol I'm using.

I got the code from here : Arduino playground - InfraredReceivers
 
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axro

New Member
I decoupled it and I still get different numbers with a button press. I put a 150ohm resistor inline with + on the receiver and a 10uF capacitor between + and 0v.

That should be enough to decouple it shouldn't it?
 
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