122 lines
3.1 KiB
Markdown
122 lines
3.1 KiB
Markdown
# ESP32-C3 Fan Controller
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An automatic server fan controller built on the ESP32-C3, featuring temperature-based relay control, OLED status display, and Home Assistant integration via MQTT.
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## Features
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- **Auto fan control** — relay switches ON/OFF based on temperature thresholds with hysteresis
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- **DHT22 sensor** — reads temperature and humidity every second
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- **SSD1306 OLED** — displays live temp, humidity, and fan state
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- **MQTT publishing** — streams sensor data and fan state to Home Assistant
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- **WiFi** — connects on boot, auto-reconnects if MQTT drops
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## Hardware
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| Component | Details |
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|---|---|
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| Microcontroller | ESP32-C3 (with onboard OLED) |
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| Sensor | DHT22 (temperature + humidity) |
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| Relay | 5V relay module (active-LOW) |
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| Fan | USB 5V fan |
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| Display | SSD1306 128×64 OLED (I2C) |
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## Wiring
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| ESP32-C3 Pin | Connected To |
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|---|---|
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| `GPIO2` | DHT22 DATA (+ 4.7kΩ pullup to 3V3) |
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| `GPIO3` | Relay IN |
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| `GPIO5` (SDA) | OLED SDA |
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| `GPIO6` (SCL) | OLED SCL |
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| `3V3` | DHT22 VCC, OLED VCC |
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| `GND` | DHT22 GND, OLED GND, Relay GND |
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Relay wiring:
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- **COM** → USB 5V
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- **NO** → Fan + (red wire)
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- Fan − (black wire) → GND
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## Configuration
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Copy `secrets.h.example` to `secrets.h` and fill in your values:
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```cpp
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#define WIFI_SSID "your_wifi_ssid"
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#define WIFI_PASS "your_wifi_password"
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#define MQTT_HOST "192.168.1.X" // Home Assistant IP
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#define MQTT_USER "mqtt_user"
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#define MQTT_PASS "mqtt_pass"
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```
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### Temperature Thresholds
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Edit these defines in `fan_controller.ino`:
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```cpp
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#define TEMP_ON 28.0 // Fan turns ON above this (°C)
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#define TEMP_OFF 25.0 // Fan turns OFF below this (°C)
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```
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## MQTT Topics
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| Topic | Direction | Payload |
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|---|---|---|
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| `esp32c3_fan/temperature` | Publish | `23.5` (°C) |
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| `esp32c3_fan/humidity` | Publish | `41` (%) |
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| `esp32c3_fan/fan/state` | Publish | `ON` / `OFF` |
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## Home Assistant Setup
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Add to `configuration.yaml`:
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```yaml
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mqtt:
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sensor:
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- name: "Room Temperature"
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unique_id: "esp32c3_temperature"
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state_topic: "esp32c3_fan/temperature"
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unit_of_measurement: "°C"
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device_class: temperature
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- name: "Room Humidity"
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unique_id: "esp32c3_humidity"
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state_topic: "esp32c3_fan/humidity"
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unit_of_measurement: "%"
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device_class: humidity
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binary_sensor:
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- name: "Server Fan"
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unique_id: "esp32c3_fan"
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state_topic: "esp32c3_fan/fan/state"
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payload_on: "ON"
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payload_off: "OFF"
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device_class: running
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```
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Restart HA after saving. Requires the **Mosquitto broker** add-on installed and running.
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## Dependencies
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Install via Arduino IDE Library Manager:
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- [U8g2](https://github.com/olikraus/u8g2) — OLED display
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- [DHT sensor library](https://github.com/adafruit/DHT-sensor-library) — DHT22
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- [PubSubClient](https://github.com/knolleary/pubsubclient) — MQTT client
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- WiFi (built-in with ESP32 board package)
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## Project Structure
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```
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esp32c3-fan-controller/
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├── fan_controller.ino # Main sketch
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├── secrets.h # WiFi & MQTT credentials (gitignored)
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├── secrets.h.example # Credentials template
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├── .gitignore
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└── README.md
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```
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## License
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MIT
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