KY-005 Infrared Transmitter: Wrong Pinout

I came across a wrong pinout description of the KY-005 breakout board which might confuse beginners and is even shown in a lot of schematics although it does not make any sense

In a lot of cases the pinout is falsely described as:

Pin 1 S Signal
Pin 2 Vcc 5 V (middle pin)
Pin 3 - Ground

The correct pinout is

Pin 1 S Signal
Pin 2 Ground (if an additional resistor has been welded to the board)
Pin 3 - Ground (if used with an external resistor)

The resistor should be about 180 Ohm for 3.3V or 220 Ohm for 5V Signal voltage to protect the diode and even more the Arduino digital pin.

As the middle pin is usually only connected to an empty pad providing Vcc to it does not create any harm, but it is completely useless /nonsense ... :wink:

It is really amazing to see how many companies' datasheets and schematics show a Vcc cable to a NC pin on the KY-005 breakout board.

Doesn't the module have more than only that "S" pin?
To me "S" means Signal.

You are right ... due to a fault the post was out before I could complete it ... Sorry for that ...

I used the "tab key" while in the editor which I immediately found to be a bad idea ... ;-((

And I guess due to the fact that this pinout is harmless it is out there since long.

If one would weld the resistor between the pads behind middle pin and ground pin, as it is ment for, AND stick with the cabling it will just add a simple heater (5V @ 220 Ohm equals about 100 mW) to the breakout board...

The module description suggests to add the required (3.3V/5V) resistor to the board. It should be noted that the KY-005 module or possible clones is not suited for beginner use.

You are right, but that was not my point:

As one can see here the sketch (and the pinout description see next post) suggests to connect the middle pin to 5V which is misleading and senseless, but a widely spread failure (copy and paste?).

As mentioned - if one welds the resistor on the IR Transmitter board AND connects as suggested this will only nicely heat the board ...

However it looks if if there could be also different layouts of KY-005, the one I know and which I checked with an Ohmmeter has two pads, one solely connected to the middle pin and the other to the GND pin. Some pictures in Webshops look different ... ?!?

However, three wires like Signal, GND and Vcc do not make sense for a board that carries only one diode.

Faulty Pinout description:

It should read

S ................Pin 3
middle ......GND if appropriate resistor is welded on the board
_ ................ GND to be used with an appropriate external resistor