4Pcs Digital 38khz Ir Receiver Sensor Module + 4Pcs 38khz Ir Transmitter Sensor Module Kit for Electronic Building Block

These are good, cheap IR boards. As other reviewers have noted, the VCC lead on the transmitter isn't actually connected to anything; it's just part of the pin header. The transmitter is just an IR LED and a resistor; the DATA pin is really the + line, so if you send it current there, it turns on. You simply bit-bang on that pin to send pulses. If you're using something like a Raspberry Pi, you won't get great range, because all of the GPIO pins are 3.3 volts. I'm using it to control an A/V receiver and have the LED right next to the panel, so it works great. If you need more range, though, you'll want to hook it up to the 5v rail via a transistor and probably also surround it with an IR reflector (as-packaged, it's an omnidirectional LED).The IR receiver works just like you'd expect, and obviously it _does_ need power, so all three pins are needed: data, vcc (5 volt, although might work with 3.3; I didn't test that), and ground. I believe data is pulled high and drops to ground when a signal is received.If you're using a Raspberry Pi with a reasonably current OS, you don't need to download any drivers; much of what you see online is old. Add the appropriate lines ("dtoverlay=gpio-ir,gpio_pin=" and "dtoverlay=gpio-ir-tx,gpio_pin=") to /boot/config.txt (or /boot/firmware/config.txt if running Debian 12). Note that, if you are going to both send AND receive (i.e. you have both lines in the config file and you've hooked up both boards), you'll need to specify which device to use (--device=) in the ir-ctl command: one will be /dev/lirc0 and the other will be /dev/lirc1; this is why some of the reviewers couldn't do both at the same time.Simply use the 'ir-ctl' command to send and receive pulses. ir-ctl can read to and write from a file, so to train it, just set it to write to a file, and then you can play those exact commands back by reading from the same.

NEW REVIEW, 4/27/21:I'd like to apologize to Dorhea; my initial problem stemmed not from faulty units, but rather misinformation from everywhere else. The reason my units weren't transmitting was because I'd been connecting the signal wire, per literally everyone's instructions, to the wrong pin on my microcontrollers. Once I discovered the proper pin, I retried these transmitters, and they finally not only worked, but performed better than I'd thought they would, with more range than I'd expected. I now fully endorse these products, I fully recommend them, and I hope I haven't turned away too much business.FIRST REVIEW:When you apply these to rebuilds of examples from the handful of tutorials available for this module, no matter how faithfully I've followed said tutorials, these modules just don't work. It's like they can't even power up. What's worse is "DORHEA" is inaccessible for support. I should've known given the lack of reviews or questions. If you're reading this, try a different company, for instance, the equivalent models from Gikfun. In fact, I just bought their IR transmitters. You'll probably have better luck with them.

I use these on a Raspberry Pi Zero W for a very specific purpose: to monitor if kodi is playing and when it stops playing, turns the TV off (because I have a tendency to fall asleep). My TV doesn't support the power off signal via HDMI, so I had to make something work the old IR way. I did struggle a bit getting it setup, but in the end, I got it.I hooked up the transmitter to 5v and receiver to 3v and used GPIO pins for signal. I couldn't use both receiver and transmitter at the same time, the pi only wants one or the other enabled in /boot/config.txt, but for my purposes that was fine. I loaded the receiver to record the IR signal, then once I had it, I disabled it and enabled the transmitter to send that signal. Good thing to know here: the pin #s it wants are the GPIO numbers, NOT the pin numbers. Once I got that sorted I was good.I can't speak to how well it does with distance, since I have the pi stashed behind the TV and the transmitter sticking out just far enough for the TV to be able to pick it up. Overall I'm happy, the price was good and it works for my need.

This Ir transmitter doesn’t work past 5 feet, but the receivers on the other hand, are amazing. I’ve installed multiple on remote controls I was building and they work flawlessly even from across a 20ft room.

These ir modules are great, I like the led indicator, displays it codes being revived and sent, these will be very useful for my iot projects!

Lacks power! As it turns out, the Vcc pin on the transmitter is a dummy, not actually tied to anything. All the current that reaches the IR LED is also driving the resistor/indicator LED combo too. That makes no sense to me. Why would they do that? They could have lowered their production costs (only a 2-pin header), reduced the size, and given the user a heads-up as to what they were getting.

This is my bad, but transmitter is so bad - the range of this module is less than 1 meter. Don’t know why you need that. Receiver works fine so 3 stars :)

The receiver works fine, but the transmitter has no range. I got mine to work by taping it to the projector I was attempting to control.The LEDs on the transmitters also came mangled and bent in all directions from the factory. It was obvious that this wasn't a shipping issue because if they were pointing properly when packaged, then they would have been protected in the nook of the circuit board.Other reviews have pointed out that the 5V VCC pin on the transmitter isn't connected and the DATA line is actually what powers the indicator LED and the output LED. This is not good and means that standard microcontrollers will not be able to deliver it enough mA to get any decent range.Also, for some reason the indicator LEDs on the transmitters I received were not all the same color. Some red, some blue. It's not a problem -- it just seemed odd.