Board and part

ESP32-C3 IR Receiver Simulator: Wiring, Code and a Live Circuit

This is a 38 kHz IR receiver wired to an ESP32-C3 DevKitM-1 with a remote control beside it, decoded live with the IRremote library: open it in the editor, press a button on the remote, and the serial monitor prints its command code.

Run it in the editor Read the code

3.3 V logic
Library: IRremote.hpp
OUT on GPIO 4
NEC protocol, 38 kHz

ESP32-C3 · IR Receiverlive0.000 s 0.00x

Click to open it in the editor

The circuit itself, running on the simulator with the sketch below. Press what can be pressed; click anything else to open it in the editor.

Connections

Wiring the IR Receiver to the ESP32-C3

Three wires to the receiver: power, GND, and OUT to GPIO 4. The remote speaks NEC, the protocol of most cheap kit remotes.

Every connection in the circuit above, with the board’s own pin names.

IR Receiver pin	ESP32-C3 pin	Why
VCC	3V3	The VS1838B-style receiver runs from 2.7 to 5.5 V.
GND	GND	Ground.
OUT	GPIO 4	Low while a 38 kHz burst arrives, high otherwise: the demodulated code.
IR (light)	The remote	In the editor the infrared light path is drawn as a gray wire from the remote.

Power

Power the receiver from 3V3 on the ESP32-C3: its output then swings to 3.3 V, the board’s own level. Fed from 5 V, its output would idle at 5 V on a 3.3 V pin.

Pins to leave alone on the ESP32-C3

GPIO 8 carries the onboard LED and GPIO 9 is the BOOT button, and both are also the default I2C pins. GPIO 2, 8 and 9 are strapping pins, and only GPIO 0 to 4 can read an analog voltage.

On a real bench

The ESP32-C3 DevKitM-1 is small enough to sit on one breadboard with room for the IR Receiver beside it. Its USB port goes through a USB-to-serial chip; the cheaper SuperMini boards use the C3’s own USB, where Serial needs USB CDC on boot turned on in the IDE.

The sketch

The code, and what it does.

The sketch the circuit above runs. Open it in the editor, change a line and press Run: it compiles in your browser.

IR receiver on ESP32-C3 GPIO 4

#include <IRremote.hpp>

const int IR_PIN = 4;   // OUT, GPIO 4

void setup() {
  Serial.begin(115200);
  IrReceiver.begin(IR_PIN);
  Serial.println("Point the remote and press a button");
}

void loop() {
  if (IrReceiver.decode()) {
    if (!(IrReceiver.decodedIRData.flags & IRDATA_FLAGS_IS_REPEAT)) {
      Serial.print("Command: 0x");
      Serial.println(IrReceiver.decodedIRData.command, HEX);
    }
    IrReceiver.resume();   // ready for the next one
  }
}

IrReceiver.begin(IR_PIN) starts the IRremote library listening on the pin. decode() returns true once a whole code has arrived, and decodedIRData.command holds the button’s command byte, 0x47 for the button pressed in this demo.

Holding a button makes an NEC remote send short repeat frames, which the library flags with IRDATA_FLAGS_IS_REPEAT. The sketch prints only the first frame of each press. resume() must be called after each code or nothing more is decoded.

Serial.begin(115200) opens the serial monitor. Serial is UART0, at 115200 baud in this sketch.

Pitfalls

Common mistakes with the IR Receiver on the ESP32-C3

Old IRremote code

Sketches written for IRremote 2.x use IRrecv irrecv(pin), irrecv.enableIRIn() and results.value. Version 3 and later use IrReceiver and decodedIRData, as here. Mixing the two is the most common reason an IR sketch will not compile.

Forgetting resume()

After decode() returns true, the library holds the code until resume() is called. Leave it out and the first button press is the only one you ever see.

Using GPIO 8 or 9

GPIO 8 drives the onboard LED and GPIO 9 is the BOOT button, and both are strapping pins read at power-on. Wired to the receiver output, either can stop a real board from booting. GPIO 4 and GPIO 5 are free of both.

FAQ

Questions and answers

Can I simulate an IR remote with an ESP32-C3 DevKitM-1?

Yes. The circuit at the top of this page is an ESP32-C3 DevKitM-1 with a IR receiver and remote, running in your browser on a simulated ESP32-C3 (RISC-V). Click a button on the simulated remote: it sends a real NEC frame, which the receiver demodulates onto the pin. Press Run it in the editor to change the wiring or the code; it is free and needs no account.

How do I find my remote’s codes?

Run this sketch and press each button: the command printed is the code to compare against. Address and command are both in decodedIRData if you need to tell two remotes apart.

Why does every press print FFFFFFFF?

That is the repeat code of an NEC remote as old versions of the library reported it. The current library flags repeats instead, which the sketch checks.

Which receiver is this?

A three-pin 38 kHz demodulating receiver like the VS1838B or TSOP38238. Check the pin order on yours: it differs between makers.

Build your own IR Receiver project

Open this circuit in the editor, change the wiring or the code, and keep your version in a free account.

Start building free Open the editor