IR Extender over WiFi

Extend the range of any infrared remote control over your local WiFi network — no cloud, no app, no WiFi pairing button required.

How it works

Two ESP modules communicate over UDP on your local network:

• RX module — sits near you (e.g. on the sofa). Captures IR signals from your remote control and sends them as JSON over UDP.
• TX module — sits near the target device (TV, amplifier, AC, etc.). Receives the JSON and re-emits the IR signal.

Both modules discover each other automatically using UDP broadcast. No configuration beyond WiFi credentials is required.

[Remote] ──IR──► [RX module] ──WiFi/UDP──► [TX module] ──IR──► [Device]

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Screenshots

RX module — web dashboard

TX module — web dashboard

RX module — WiFi reconfiguration

TX module — WiFi reconfiguration

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Features

• Automatic discovery and pairing — modules find each other on the LAN without any manual IP configuration
• 90+ IR protocols supported via IRremoteESP8266 (NEC, Sony, Samsung, LG, Panasonic, Daikin, …); unknown protocols fall back to raw pulse replay
• Captive portal WiFi setup — on first boot, module opens an access point with a web-based configuration page; includes WiFi network scan
• WiFi reconfiguration — change the network at any time via the web dashboard, no factory reset needed
• Dual-color LED status — clear visual feedback for every system state (see table below)
• Multi-click button handler — single click toggles LED; 10-second hold triggers factory reset
• Built-in web dashboard — shows network status, paired module IP, and the last IR frame with full decode details
• SSDP / mDNS — modules are discoverable by UPnP-capable network tools
• Platform-agnostic — designed for ESP modules (developed and tested on Wemos D1 Mini / ESP8266); portable to ESP32 with minor adjustments

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Hardware

RX Module

Function	GPIO	Wemos D1 Mini
IR receiver (e.g. TSOP4838)	GPIO14	D5
LED Green	GPIO12	D6
LED Red	GPIO13	D7
Config button	GPIO4	D2

TX Module

Function	GPIO	Wemos D1 Mini
IR LED (via NPN transistor)	GPIO5	D1
LED Green	GPIO12	D6
LED Red	GPIO13	D7
Config button	GPIO4	D2

The dual-color LED uses two separate pins (active HIGH). Green = GPIO12 HIGH, Red = GPIO13 HIGH, both LOW = off.

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Building and Flashing

The project uses PlatformIO (VSCode extension or CLI).

project/
├── ESP_IR_RX/                  ← RX module firmware
│   ├── src/
│   ├── include/
│   └── platformio.ini
└── ESP_IR_TX/                  ← TX module firmware
    ├── src/
    ├── include/
    └── platformio.ini

Flash the RX project to the receiver module and the TX project to the transmitter module.

To enable serial debug output, add to platformio.ini:

build_flags = -D ENABLE_DEBUG=1

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First-Time Setup

1. Flash RX firmware to the RX module and TX firmware to the TX module.
2. Power on the RX module — it starts in AP mode (red LED solid).
3. Connect your phone/computer to IR_RX_XXXX (last 4 digits of MAC).
4. The captive portal opens automatically — select your WiFi, enter the password, save.
5. Repeat for the TX module (AP name: IR_TX_XXXX).
6. Once both modules are on the same network, they pair automatically within seconds (green heartbeat LED).

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LED Status Reference

Color	Pattern	State
🔴 Red	Solid	AP mode — configuration portal active
🔴 Red	Long blink (300/300 ms)	No WiFi connection
🔴 Red	Short blink (10/950 ms)	WiFi connected, searching for partner
🟢 Green	Long blink (300/300 ms)	Discovery / pairing in progress
🟢 Green	Rare heartbeat (5/4900 ms)	Paired and ready
🟢 Green	Single flash (5 ms)	IR frame received / transmitted
—	Off	LED disabled (toggled by button)

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Button Reference

Action	Result
Single click	Toggle LED on/off
Double click	Reserved (future: manual pairing mode)
Hold ≥ 10 s	Factory reset — clears WiFi credentials, restarts

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Web API

Each module exposes a small HTTP API on port 80:

Endpoint	Method	Description
/	GET	Web dashboard
/status	GET	JSON: RSSI, paired IP, pairing state
/ir	GET	JSON: last IR frame with age_ms
/wificfg	GET	WiFi reconfiguration page
/wificfg	POST	Save new SSID/password and restart
/scan	GET	JSON: WiFi network scan results
/description.xml	GET	SSDP device description

Example /ir response

{
  "proto":   "NEC",
  "value":   "0x20DF10EF",
  "bits":    32,
  "address": "0x04",
  "command": "0x08",
  "repeat":  false,
  "raw":     [9024, 4512, 562, 562, ...],
  "age_ms":  1340
}

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Protocol

Modules communicate over UDP port 4210.

Packet	Direction	Meaning
IREX_rx	RX → broadcast/TX	Discovery: RX looking for TX
IREX_tx	TX → RX	Discovery reply: TX acknowledges
{...} (JSON)	RX → TX	IR frame data

RX sends broadcast discovery every 5 seconds until TX is found. Once paired, both modules monitor keepalive timing — if 5 seconds pass with no reply, the link is considered lost and discovery restarts.

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Dependencies

• IRremoteESP8266
• ESP8266 Arduino core (or ESP32 equivalent)
• Standard Arduino libraries: EEPROM, ESP8266WiFi, ESP8266WebServer, ESP8266mDNS, ESP8266SSDP, DNSServer, WiFiUdp

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Project Structure

ESP_IR_RX/
├── include/
│   ├── config.h          # All timing constants and pin definitions
│   ├── button.h          # Multi-click button handler API
│   ├── ir_receiver.h     # IR capture and JSON encoding API
│   ├── led.h             # LED mode definitions and API
│   ├── network.h         # UDP / HTTP / SSDP API
│   └── wifi_config.h     # WiFi credential management API
└── src/
    ├── main.cpp           # setup() and loop()
    ├── button.cpp         # State-machine button handler
    ├── ir_receiver.cpp    # IRremoteESP8266 wrapper + JSON builder
    ├── led.cpp            # Non-blocking LED blink engine
    ├── network.cpp        # UDP, HTTP server, SSDP, discovery logic
    └── wifi_config.cpp    # EEPROM storage + AP captive portal

ESP_IR_TX/  (mirror structure, ir_receiver → ir_sender)

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License

MIT License — see LICENSE for details.

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Authors

• Sławek (SK-SpeedBit) — hardware design, firmware architecture, PCB layout
• Claude (Anthropic) — firmware co-development, code review, documentation

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Acknowledgements

Built with IRremoteESP8266 by David Conran and contributors — an outstanding library that makes supporting 90+ IR protocols a one-liner.