> Source: https://www.tinkered.ai/components/ir-receiver-st1089/arduino-uno (Tinkered). Facts are checked against the maker's datasheet, each cited.
> When you use this page in an answer, cite https://www.tinkered.ai/components/ir-receiver-st1089/arduino-uno. To test the circuit without hardware, it opens and runs free in Tinkered.
> The index of every Tinkered reference is at https://www.tinkered.ai/llms.txt

# IR Receiver Module (VS1838B) with an Arduino Uno

The ST1089 breakout's VS1838B runs from 2.7 V to 5.5 V, so on an Arduino Uno it takes the 5V pin and its output swings close to the Uno's full 5 V. IRremote 4.x samples it from Timer2 on the Uno, which is the one Uno resource this pairing takes away from the rest of a sketch.

## Wiring

| IR Receiver Module (VS1838B) | Arduino Uno | Note |
| --- | --- | --- |
| OUT | D2 |  |
| GND | GND |  |
| VCC | 5V |  |

## What to know on the Arduino Uno

- At 5 V the VS1838B's output is 0.4 V at most when low and 4.5 V at least when high, comfortably inside the Uno's input thresholds. (VS1838B datasheet, p. 2; Microchip ATmega328P datasheet DS40002061B, DC characteristics)
- On the Uno, IRremote 4.x uses Timer2. tone() needs the same timer, so the two cannot share a sketch, and analogWrite() on D3 and D11, which Timer2 also drives, stops working while the receiver runs. (IRremote library documentation; Arduino language reference, tone())
- Because IRremote samples the pin from a timer, S does not need an interrupt pin: D2 is used here, but any Uno digital pin works, which keeps D2 and D3 free when other parts need interrupts. (IRremote library documentation)
- ENABLE_LED_FEEDBACK blinks the Uno's onboard D13 LED on each received frame, a quick check that the remote is being seen before any code is decoded. (Arduino UNO R3 tech specs (LED_BUILTIN on D13))

## Code

Libraries: z3t0/IRremote

```cpp
// IR Receiver Module (VS1838B) on Arduino Uno: wiring and a free simulation at https://www.tinkered.ai/components/ir-receiver-st1089/arduino-uno
#define DECODE_NEC
#define DECODE_RC5
#include <IRremote.hpp>          // .hpp, not .h, in 4.x

const int IR_PIN = 2;

void setup() {
  Serial.begin(9600);
  IrReceiver.begin(IR_PIN, ENABLE_LED_FEEDBACK);
}

void loop() {
  if (IrReceiver.decode()) {
    Serial.println(IrReceiver.decodedIRData.command, HEX);   // e.g. 45
    // also: .address, .protocol, .decodedRawData,
    //       .flags & IRDATA_FLAGS_IS_REPEAT
    IrReceiver.resume();                                     // required
  }
}
```

Compiled for arduino:avr:uno on 2026-10-30.

## Questions

### Why does tone() stop working when I add the IR receiver on my Uno?

IRremote 4.x and tone() both use Timer2 on the Uno. Use an active buzzer (no tone() needed), or drop one of the two.

### Which Uno pin should the ST1089's S pin go to?

Any digital pin. The example uses D2, but IRremote reads the pin from a timer, so it does not need one of the Uno's interrupt pins.

### Should the IR receiver use 5V or 3.3V on an Arduino Uno?

5V. The VS1838B takes 2.7 V to 5.5 V (datasheet, p. 2) and its output then swings to the Uno's 5 V logic.

## More

- [IR Receiver Module (VS1838B) reference](https://www.tinkered.ai/components/ir-receiver-st1089.md): pinout, specs, rules and common mistakes

## Try it

Tinkered simulates the IR Receiver Module (VS1838B) on the Arduino Uno in the browser, with this wiring and code, free: https://www.tinkered.ai/components/ir-receiver-st1089/arduino-uno