Overview
The HX1838 is a 38 kHz infrared remote control kit that gives any microcontroller "TV remote" capabilities — receive button presses from across the room, decode them in software, and trigger any action you want. The kit includes a 17-key NEC-protocol remote, an HX1838 IR receiver module, three jumper wires, and a 5mm IR LED you can use for transmitting back.
The receiver module has just three pins (VCC, GND, OUT) and works on 3.3V or 5V — ideal for Arduino, ESP32, Raspberry Pi, and Pico. The output is an active-LOW digital signal that pulses in NEC protocol patterns; libraries like IRremote decode the patterns into 32-bit hex codes you can match in your sketch.
At a Glance
Operating Voltage
2.7 - 5.5V
Carrier Frequency
38 kHz
Protocol
NEC
Range
~8 meters (line-of-sight)
Receiver Pins
VCC, GND, OUT
Remote Buttons
17 (digits + nav + OK)
Specifications
| Parameter | Value |
| Receiver IC | HX1838 / VS1838B (compatible variants) |
| Operating Voltage | 2.7V - 5.5V |
| Operating Current | ~1.5 mA (idle) |
| Carrier Frequency | 38 kHz |
| Sensitivity | 0.35 mW/m² |
| Reception Distance | ~8 meters (line-of-sight) |
| Reception Angle | ±45° |
| Output | Active-LOW digital pulse train |
| Protocol | NEC (32-bit codes, 8-bit address + 8-bit command) |
| Remote Type | 17-key infrared remote, CR2025 battery (included) |
| Remote Buttons | 0-9, *, #, OK, ↑ ↓ ← → |
| Receiver Dimensions | ~17 × 9 mm |
Pinout Diagram
Wiring Guide
Arduino Wiring
Three wires — VCC, GND, and the OUT signal. Use any digital pin that supports interrupts (D2 or D3 on UNO) so the IRremote library can react quickly.
| Receiver Pin | Arduino Pin |
|---|---|
| VCC | 5V |
| GND | GND |
| OUT (S) | D2 (or any digital pin) |
Tip: The receiver pin labeled "S" or "OUT" is sometimes hard to identify. Look for the metal-domed face of the IR receiver — the pin closest to the LED indicator usually goes to OUT. Test with a multimeter (idle HIGH).
ESP32 Wiring
| Receiver Pin | ESP32 Pin |
|---|---|
| VCC | 3V3 or 5V (both work) |
| GND | GND |
| OUT | GPIO 15 (or any input GPIO) |
Raspberry Pi Wiring
The receiver works at 3.3V — wire OUT directly to a Pi GPIO. For best results, use the LIRC kernel driver or the pigpio Python bindings.
| Receiver Pin | Raspberry Pi Pin |
|---|---|
| VCC | Pin 1 (3.3V) |
| GND | Pin 6 (GND) |
| OUT | Pin 11 (GPIO 17) |
Raspberry Pi Pico Wiring
| Receiver Pin | Pico Pin |
|---|---|
| VCC | 3V3 (OUT) |
| GND | GND |
| OUT | GP15 (or any input GPIO) |
Code Examples
Arduino — Decode Remote Buttons
ir_remote.ino
// HX1838 IR Remote - Arduino Example
// Library: IRremote by shirriff (v3+ syntax)
#include <IRremote.hpp>
const int IR_PIN = 2;
void setup() {
Serial.begin(9600);
IrReceiver.begin(IR_PIN, ENABLE_LED_FEEDBACK);
Serial.println("Press a button...");
}
void loop() {
if (IrReceiver.decode()) {
Serial.print("Code: 0x");
Serial.println(IrReceiver.decodedIRData.command, HEX);
IrReceiver.resume(); // ready for next code
}
}
Arduino — Map Codes to Actions
ir_actions.ino
// React to specific buttons. Run the previous sketch first
// to learn each button's hex code, then fill in below.
#include <IRremote.hpp>
const int IR_PIN = 2;
const int LED_PIN = 13;
void setup() {
pinMode(LED_PIN, OUTPUT);
IrReceiver.begin(IR_PIN);
}
void loop() {
if (IrReceiver.decode()) {
switch (IrReceiver.decodedIRData.command) {
case 0x46: digitalWrite(LED_PIN, HIGH); break; // UP
case 0x15: digitalWrite(LED_PIN, LOW); break; // DOWN
case 0x40: /* OK button */ break;
}
IrReceiver.resume();
}
}
Raspberry Pi (Python — pigpio)
ir_rpi.py
#!/usr/bin/env python3
# Install: sudo apt install pigpio python3-pigpio
# Start daemon: sudo systemctl enable --now pigpiod
# Quick raw-pulse capture using pigpio
import pigpio, time, sys
GPIO_PIN = 17
pi = pigpio.pi()
pi.set_mode(GPIO_PIN, pigpio.INPUT)
last_tick = 0
def cbf(gpio, level, tick):
global last_tick
diff = pigpio.tickDiff(last_tick, tick)
last_tick = tick
print(f"{level} after {diff} us")
cb = pi.callback(GPIO_PIN, pigpio.EITHER_EDGE, cbf)
print("Press buttons. Ctrl-C to stop.")
try:
while True: time.sleep(1)
except KeyboardInterrupt:
cb.cancel()
pi.stop()
Raspberry Pi Pico (MicroPython)
ir_pico.py
# IR receiver on Pico - MicroPython
# Use the micropython-ir library by peterhinch
# https://github.com/peterhinch/micropython_ir
from machine import Pin
from ir_rx.nec import NEC_8
def callback(data, addr, ctrl):
if data > 0:
print('Code: 0x{:02X} Addr: 0x{:04X}'.format(data, addr))
ir = NEC_8(Pin(15, Pin.IN), callback)
print("Press buttons...")
while True:
pass
Frequently Asked Questions
My remote isn't doing anything. What's wrong?
Three things to check: (1) the small CR2025 battery — peel off the plastic insulator tab if you haven't, (2) the receiver wiring — VCC and GND swapped is the most common mistake, (3) point the remote at the receiver's metal-domed face from no more than 1m away while testing.
Why do I get the same hex code for different buttons?
If you're seeing 0xFFFFFFFF, that's a "repeat" code (NEC protocol sends repeats while a button is held). Filter those out by ignoring 0xFFFFFFFF and 0xFFFFFFFE in your switch statement.
Can I use any TV remote with this receiver?
Most modern TV remotes use NEC, RC5, RC6, or Sony SIRC protocols at 38 kHz — all of which the IRremote library can decode. Just call
IrReceiver.printIRResultShort() to see what protocol your remote uses.How do I make my Arduino TRANSMIT IR codes (e.g., to control a TV)?
Connect the included 5mm IR LED to a digital PWM pin (D3 on UNO) through a 220Ω resistor and use the IRremote library's
IrSender.sendNEC(). The same library handles both receive and send.Is the IR signal blocked by furniture or walls?
Yes. IR is line-of-sight only. It also fails through smoked glass and gets confused by direct sunlight or heavy fluorescent flicker. Mount the receiver where it has clear line-of-sight to the user.
Can I run multiple IR receivers in the same room?
Yes. Each microcontroller decodes the same NEC pulses independently — the IR signal is broadcast. If you want different remotes controlling different boards, use remotes with different address bytes and filter by address in software.