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Topic: How to identify Ground / Data / Voltage supply? (Read 889 times) previous topic - next topic

thecoon

Hi,

I bought an IR receiver and IR transmitter:

Receiver:


Transmitter:


How can I find out what each of the three pins are? It isn't written anywhere I can see. There's only written an "S", "-", "R1" and "Keyes".

Your help is much appreciated :D

Thanks!

thecoon

I'm afraid of damaging the components if I do it wrong. Is there any risk of doing so (apart from killing up the IR LED using no resistor)?

thecoon

Ok, so I found the datasheet for the IR receiver :)

http://www.alldatasheet.com/datasheet-pdf/pdf/26604/VISHAY/TSOP1838.html

I'll be interested in the datasheet for the IR LED too, to know how small a resistor I can use (for maximum IR lighht emission strength).

Grumpy_Mike

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to know how small a resistor I can use (for maximum IR lighht emission strength).

That is likely to depend on how you drive it. An arduino should not be asked to deliver more than 40mA and most IR LEDs can take more than this.
Typically you can use a 33R resistor if you drive it with a transistor.

thecoon

Thanks for the heads up! I'm driving it with the Arduino. :)

Hmmm. I don't understand why the IR Transmitter is composed of an IR LED with 2 pins connected to some other and seemingly meaningless component with 3 output pins.

Grumpy_Mike

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some other and seemingly meaningless component with 3 output pins.

Could be a transistor already on the board.
Any chance of a photo of the other side.

thecoon

Here is the other side:



There are two little "metal squares", one above each of the two right-most pins. Perhaps that is something. I'm still trying to find this at alldatasheet.com. No luck yet, but the search continues :)

MarkT

This is standard servo connector layout.  - means ground, + is supply, S is signal.

Note that the solder pads are round except for one that is square - that means its pin number 1,
should you have a schematic to compare to.
[ I won't respond to messages, use the forum please ]

thecoon

Thanks alot! :D I'm going to write these things down for further reference :)

I'm building a radio-to-infrared interface, so I can control my devices from a greater distance :) If it works well I will maybe to a Web-to-infrared interface as well :)

1ChicagoDave

Have you tried googling "Keyes IR emitter" and/or "Keyes IR receiver"?

I found a few tutorials, info, and this photo with pin connections.

Zapro

There is a reason for that IR-emitter board to look a bit strange - it's meant for a pushbutton with pullup resistor - it's simply being re-purposed as a carrier for the IR LED.

Grumpy_Mike


I don't understand why the IR Transmitter is composed of an IR LED with 2 pins connected to some other and seemingly meaningless component with 3 output pins.

I can't see this component from your photograph. In fact I can't see any components at all.
I would connect it up with a 220R seriese resistor to 5V and ground and measure the voltage across the LED. Look at the LED through the electronic viewfinder of a camera to see which way round it lights. Then drive it with a transistor and work out the resistor to give you 80mA current through it.

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