IR receiver (VS1838B) with NodeMCU ESP8266 — wiring and decoder code

An IR receiver turns any old remote into a controller for your NodeMCU — switch a relay, change an LED colour or drive a menu without a phone.

The VS1838B needs just one signal wire. Put OUT on D5, power it from 3V3, and the sketch prints the protocol, address and command of each button so you can copy them into your own project. Keep the receiver off D8: its idle-HIGH output fights the ESP8266’s boot strapping.

Wiring

Board quirks

• The receiver’s output idles HIGH. On D8 (GPIO15) that would stop the NodeMCU booting, because GPIO15 must be LOW at reset. D5, D6, D7, D1 and D2 are safe.
• IRremote’s LED feedback is disabled in the sketch: the NodeMCU’s on-board LED sits on D4 (GPIO2), a boot pin, and flashing it on every signal is more confusing than useful.
• For air-conditioner remotes (long frames with temperature and mode), the ESP8266-specific IRremoteESP8266 library decodes far more protocols. IRremote is used here because the same sketch also runs on Uno and ESP32.
• The VS1838B is tuned to 38 kHz. Fluorescent tubes and direct sunlight can produce junk “Unknown protocol” lines — shade the receiver.

Code

// VS1838B IR receiver on a NodeMCU (ESP8266) with IRremote 4.x.
// VCC → 3V3, GND → GND, OUT → D5 (GPIO14).
// Press buttons on any TV / set-top-box remote and note the codes for your own project.
#include <IRremote.hpp>

const uint8_t IR_PIN = D5;  // not D8: the receiver idles HIGH and GPIO15 must be LOW at boot

void setup() {
  Serial.begin(115200);
  Serial.println();
  IrReceiver.begin(IR_PIN, DISABLE_LED_FEEDBACK);  // the on-board LED is on D4, a boot pin — leave it alone
  Serial.println("IR receiver on D5 (GPIO14) - press a remote button");
}

void loop() {
  if (!IrReceiver.decode()) return;
  IRData &d = IrReceiver.decodedIRData;
  if (d.flags & IRDATA_FLAGS_IS_REPEAT) {
    Serial.println("(repeat)");
  } else if (d.protocol == UNKNOWN) {
    Serial.println("Unknown protocol (noise, or an AC remote with long frames)");
  } else {
    Serial.printf("%s  address 0x%04X  command 0x%02X\n", getProtocolString(d.protocol), d.address, d.command);
  }
  IrReceiver.resume();
}

// VS1838B IR receiver on a NodeMCU (ESP8266) with IRremote 4.x.
// VCC → 3V3, GND → GND, OUT → D5 (GPIO14).
// Press buttons on any TV / set-top-box remote and note the codes for your own project.
#include <IRremote.hpp>

const uint8_t IR_PIN = D5;  // not D8: the receiver idles HIGH and GPIO15 must be LOW at boot

void setup() {
  Serial.begin(115200);
  Serial.println();
  IrReceiver.begin(IR_PIN, DISABLE_LED_FEEDBACK);  // the on-board LED is on D4, a boot pin — leave it alone
  Serial.println("IR receiver on D5 (GPIO14) - press a remote button");
}

void loop() {
  if (!IrReceiver.decode()) return;
  IRData &d = IrReceiver.decodedIRData;
  if (d.flags & IRDATA_FLAGS_IS_REPEAT) {
    Serial.println("(repeat)");
  } else if (d.protocol == UNKNOWN) {
    Serial.println("Unknown protocol (noise, or an AC remote with long frames)");
  } else {
    Serial.printf("%s  address 0x%04X  command 0x%02X\n", getProtocolString(d.protocol), d.address, d.command);
  }
  IrReceiver.resume();
}

Library: IRremote (Armin Joachimsmeyer (shirriff, z3t0)) — compiled with IRremote 4.7.1.

Expected serial output

IR receiver on D5 (GPIO14) - press a remote button
NEC  address 0x0000  command 0x45
(repeat)
NEC  address 0x0000  command 0x46
Unknown protocol (noise, or an AC remote with long frames)

IR receiver on D5 (GPIO14) - press a remote button
NEC  address 0x0000  command 0x45
(repeat)
NEC  address 0x0000  command 0x46
Unknown protocol (noise, or an AC remote with long frames)

Common errors