Overview

The VS1838B (and equivalent HX1838 / TSOP1838) is a miniaturized 38 kHz infrared receiver module used for IR remote control command decoding in electronics kits (Elegoo, SunFounder) and consumer appliances.

It integrates a PIN photodiode, high-gain preamplifier, automatic gain control (AGC), bandpass filter tuned to 38 kHz, and a demodulator inside a metal-shielded package. When it detects a 38 kHz modulated IR light signal from a remote, it strips away the 38 kHz carrier frequency and outputs clean active-LOW digital logic pulses directly to a microcontroller pin.

Quick reference

Operating Voltage (VCC)2.7 V to 5.5 V DC (5.0 V nominal)
Carrier Frequency38.0 kHz (standard consumer IR remote frequency)
Peak Wavelength940 nm (Infrared spectrum)
Reception Range15 m to 18 m
Angle of Directivity±45∘\pm 45^\circ (90∘90^\circ half-power cone)
Output StateIdle: HIGH (3.3V/5V); Active 38kHz IR burst: LOW (0V)
Quiescent Current0.5 mA to 1.5 mA

Pinout

Standard Metal-Shielded Component Pins (Facing front bubble, pins down)

text
        ┌─────────┐
        │ [VS1838]│  (Front lens bubble facing you)
        └─────────┘
          │  │  │
          1  2  3
PinNameTypeDescription
1OUT / DATDigital OutputDemodulated digital output (Active-LOW, connects to MCU GPIO)
2GNDPowerGround (0 V)
3VCCPowerSupply voltage (+2.7 V to +5.5 V DC)
Note

Pinout Warning for KY-022 Breakout PCBs: On some 3-pin KY-022 PCB modules, the pin order on the header connector from left to right is DAT - VCC - GND or GND - VCC - DAT. Always check PCB silk markings!

Specifications

ParameterSymbolMinTypMaxUnitConditions
Supply VoltageVSV_{S}2.75.05.5VDC
Supply CurrentISI_{S}0.40.61.5mANo IR signal
Carrier Frequencyf0f_{0}—38.0—kHzCenter frequency
Low Output VoltageVOLV_{OL}—0.20.4VDuring 38 kHz IR burst (IOSL=0.5 mAI_{OSL} = 0.5\text{ mA})
High Output VoltageVOHV_{OH}VS−0.5V_{S}-0.5—VSV_{S}VIdle / No IR signal
Minimum Burst Lengthtburstt_{burst}10——cycles10 cycles of 38 kHz (≈260 μs\approx 260\text{ }\mu\text{s})

IR Protocol Demodulation (NEC Protocol Example)

The VS1838B automatically strips the 38 kHz carrier wave from incoming remote signals:

text
Sender (38kHz IR LED Burst) ───█████─────────█████───────
                                │             │
VS1838B Output (OUT Pin)   ───┐ │ ┌─────────┐ │ ┌─────────
                              └─┘ └─────────┘ └─┘
                             (Active-LOW Pulse Payload)
  • NEC Protocol Start Frame: 9 ms continuous 38 kHz burst (LOW pulse) followed by a 4.5 ms space (HIGH).
  • Bit 0: 562.5 µs burst followed by 562.5 µs space (1.125 ms1.125\text{ ms} total).
  • Bit 1: 562.5 µs burst followed by 1.6875 ms space (2.25 ms2.25\text{ ms} total).

Wiring

VS1838B Component Pin→Microcontroller (Arduino Uno / ESP32)
1 (OUT)Digital Input Pin with Interrupts (e.g. D11 / GPIO15)
2 (GND)GND
3 (VCC)5V (or 3.3V)

Common mistakes

  • Reversing VCC and GND: Connecting power in reverse heats up the internal IC and destroys the photodiode preamplifier.
  • Interference from compact fluorescent lights (CFL) / Sunlight: Direct sunlight or electronic ballast fluorescent lamps emit strong 38 kHz modulated infrared noise. Keep the sensor shielded from direct sunlight.
  • Forgetting Active-LOW logic: The OUT pin stays HIGH at rest and pulses LOW during IR signals. Hardware interrupt triggers should use FALLING or CHANGE edge detection.

Notes

  • Compatible with standard open-source libraries such as IRremote (Arduino) and ESPHome remote_receiver component.

Assets & downloads