DevLab_IR

Arduino library for the IRM-V838M3 infrared receiver module (38 kHz) using the DevLab Device Protocol (DDP) over I2C.

The module is a PY32F003 that decodes NEC frames in firmware and exposes them through I2C. This library wraps the shared DevLabDDP master and the DevLab_Interface DevLab_I2C_Orchestrator bus class into one DevLab_IR object. Firmware: unit_firmware_i2c_irm_v838m3_py32.

Compatible with ESP32, RP2040/RP2350, STM32 and AVR.

Features

• Device identification (Device ID 0x0111) before any command
• poll() returns address, command, repeat and error flags in one call
• Low-level readCarrier(), readStatus() and readRawFrame()
• I2C address scan and reassignment (0x08 to 0x77), default address 0x30
• Bus recovery (beginRecovered) for a slave left mid-transaction

Quick Start

#include <Arduino.h>
#include <Wire.h>
#include <DevLab_IR.h>

DevLab_IR ir(Wire, DevLab_IR::DEFAULT_ADDRESS, 400000);

void setup() {
  Serial.begin(115200);
  if (!ir.beginRecovered(SDA, SCL)) {
    Serial.println("IRM-V838M3 not found");
    while (1);
  }
}

void loop() {
  DevLab_IR_Frame f;
  if (ir.poll(f) && f.newFrame && f.valid) {
    Serial.printf("addr=0x%02X cmd=0x%02X\n", f.address, f.command);
  }
  delay(20);
}

Command map (block 0x80)

Command	Method	Response
0x80	readCarrier()	1 byte, bit0 = carrier present (output low)
0x81	readStatus()	1 byte of flags; clears event bits
0x82	readRawFrame()	4 bytes addr, ~addr, cmd, ~cmd; clears NEW_FRAME

Status bits: 0x01 new frame, 0x02 repeat, 0x04 checksum OK, 0x08 carrier now, 0x10 timing error.

Notes

• NEC only; RC5/Sony are not decoded by the firmware.
• DevLabDDP::deviceName() reports unknown for ID 0x0111 until the DDP library adds it; this does not affect identification.
• The firmware is not yet validated on hardware (see its README).

Folder Structure

DevLab_IR/
├── examples/
│   ├── i2c/{changeAddress,i2c_scanner}
│   └── ir/{readNec,irEvents}
├── src/DevLab_IR.{h,cpp}
├── library.properties
├── keywords.txt
└── LICENSE

Author

UNIT Electronics MX - Jonathan Mejorado

License

MIT License