📌 What is Hob2Hood? Hob2Hood is an automation system that allows an induction hob (cooking top) to communicate wirelessly with a kitchen range hood. It controls the ventilation fan speed and lighting based on whatthe hob’s communicates to the hood — for example, turning on the fan and lights when cooking starts, or adjusting its speed as the heat increases.
| 4 relay board | ESP32 D1 mini |
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Some hobs and hoods support Hob2Hood natively (e.g. AEG, Electrolux), using infrared (IR) communication to transmit commands.
This project replicates and enhances that functionality using an ESP32, allowing:
Manual or IR-based fan/light control
OTA (Over-The-Air) firmware updates
Web-based control interface\
🚀 What This Program Does
This firmware is running on an ESP32:
Listens to IR commands using the RMT peripheral and a TSOP4838 IR receiver.
Decodes DECODE_HASH - format signals. This is a native IRRemote library protocol that works with Hob2Hood.
Maps decoded signals to known Hob2Hood commands (Vent1–4, Light On/Off)
Controls output GPIO pins that switch relays connected to:\
Fan speed relays (Vent1–4)
Light switch
Hosts a web interface which has a serial input where commands can be typed in (via SerialHTML)
These real-time command reception works via WebSocket
Supports OTA updates, with IR and SerialHTML safely paused during update
Implements a watchdog timer for reliability
🔌 Wiring / Pinout (ESP32 to Hood)
Function ESP32 GPIO\
IR Receiver GPIO 5 Connect IR sensor OUT pin here
Fan Speed (1) GPIO 32 Level shifter FAN HIGH or LOW
Fan Speed (2/3) GPIO 27 Not used relay needs to be HIGH allways
Fan On/Off Ctrl GPIO 19 Main ventilation power ON/OFF
Light On/Off GPIO 25 Relay to control hood light
Built-in LED GPIO 2 Status indicator\
All output pins drive relays to control hood ventilator and light.
🌐 Web Interface (SerialHTML) Simple control page served by ESP32 to control Light and Vent speed via WebSocket.
🔧 Installation & Setup
Ensure you have the following libraries installed:\
ESPAsyncWebServer
AsyncTCP
ArduinoOTA
SerialHTML (custom or internal library)
Connect to the ESP32's IP address shown in serial output after WiFi connection.\
⚙️ Special Features
🔧 Modular structure: clean, well-organized functions.
📡 OTA integrated safely to enable over the air updates (disables IR for robustness).
🔄 Watchdog Timer (WDT) to ensure recovery from freezing/lockups covering all cores.
🌐 WiFi reconnect logic is lightweight and correct.
📲 SerialHTML abstraction for WebSerial with realtime WebSocket control.
📦 CommandQueue + xQueue usage is perfect for decoupling.
🧪 Debug info sent to serialHTML for checking incoming IR codes.
🕹️ IR Task on separate core giving robustness and responsiveness.\
🧠 IR Code Mapping
IR Code (Hex) Function
0xE208293C Light ON
0x24ACF947 Light OFF
0xE3C01BE2 Ventilation 1
0xD051C301 Ventilation 2
0xC22FFFD7 Ventilation 3
0xB9121B29 Ventilation 4
0x055303A3 Ventilation OFF\
🧪 Debugging & Logs
Open the Web Serial Monitor at ESP32Hob2Hood/serial
IR signal decoding
Fan/light command handling
OTA state
WiFi reconnection attempts
Watchdog resets (if triggered)
📸 Images
Schematic / wiring diagram
Screenshot of the web control page
Old wiring of Hood. The 3 way rocker switch was replaced by two relays. In my actual wiring i have used 3 but one is closed permanently and so has no function.
Some improvements possible.
Put a 100nF capacitor on the power supply to the ESP32
Add a 10kOhm resistor pull down on the IR receiver.
These should improve the IR receiver and produce less eroneous signals.
Add a snubber circuit to dampen the relay. I see that when the relay operates this generates bogus IR signals.
RC snubber: good for both AC/DC, but may allow some current leakage.
Diode: simple, great for DC, slows turn-off time slightly.
Zener + diode: faster turn-off, tighter voltage control.
Varistor (MOV): robust spike suppression, mainly AC use, can degrade over time.