• Author: Petru Zincenco
• Master: IA

I am creating this project because I already have a Home Assistant server running on a Raspberry Pi 3, and I want to extend its capabilities to control my stereo system and air conditioner via IR. By turning an ESP32 into an IR transceiver, I can sniff existing NEC-protocol remote commands, replay them, and even send arbitrary data over IR directly from my phone through Home Assistant.

• Home Assistant Server (Raspberry Pi 3)
  1. Connected to local Wi-Fi.
  2. Hosts ESPHome for firmware management.
  3. Manages the 3 lights directly.
• ESP32 IR Hub
  1. Connects back to Home Assistant over Wi-Fi (API/MQTT).
  2. Controls the YS-IRTM module via UART.
• YS-IRTM IR Emitter/Receiver Module
  1. 38 kHz carrier, NEC-protocol.
  2. Controls the Air Conditioner and Audio System via infrared signals

• 4-channel 3.3 V ↔ 5 V level-shifter – 11 RON

• YS-IRTM IR emitter/receiver module (38 kHz) – 22 RON

• ESP32 development board – 46 RON

• Jumper wires and breadboard

Total cost: 79 RON

• LVCC → 3.3 V
• HVCC → 5 V
• GND → ESP32 GND
• TXD (module) → level shifter → ESP32 RX
• RXD (module) ← level shifter ← ESP32 TX

• ESPHome (YAML-based configuration, OTA updates, Home Assistant integration)
• `uart` component on TX/RX pins at 9600 baud to interface with the YS-IRTM’s TTL serial
• `text_sensor` (custom lambda) for buffering and parsing incoming 3-byte payloads into HA events
• `remote_transmitter` declared (IR modulation offloaded to module’s 38 kHz carrier engine)

• YS-IRTM demodulates 38 kHz IR, decodes NEC frames internally, then emits three data bytes (User Code High, User Code Low, Command) over UART upon each valid command
• ESPHome listens on UART, accumulates up to three bytes in a small buffer, then fires an MQTT/state update and resets the buffer
• NEC repeat frames are suppressed by the module; ESPHome can apply further debouncing or grouping if needed

• To transmit, ESP32 sends a five-byte payload via `uart.write`:
  1. Address byte (default `0xA1`)
  2. Command byte `F1` (`0xF1`, trigger TX)
  3. Data byte 1 (NEC User Code High)
  4. Data byte 2 (NEC User Code Low)
  5. Data byte 3 (NEC Command)
• The module appends the inverse of the command byte automatically and generates a full NEC frame with a 9 ms leading mark, 4.5 ms space, 562 µs mark/space per bit, and final mark at 38 kHz
• On success, YS-IRTM replies over UART with the command byte (`0xF1`); silence indicates a bad payload
• ESPHome waits (e.g. 1000 ms) for the ack and can retry transmission if no response arrives

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