jazzymc
2f783dbc41
3-zone PWM fan controller (intake/central/outtake) with DS18B20 temp sensors, RPM monitoring, ST7789 LCD display, and Home Assistant integration via ESPHome native API. USB-C PD powered. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
137 lines
4.3 KiB
Markdown
137 lines
4.3 KiB
Markdown
# Rack Fan Controller
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ESP32-C6 based smart rack/cabinet fan controller with temperature monitoring, automatic PWM fan speed control, and Home Assistant integration via ESPHome.
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## Features
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- **3-zone fan control**: Intake, Central, Outtake (2 fans per zone, 6 total)
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- **Temperature monitoring**: 3x DS18B20 sensors (one per zone)
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- **RPM monitoring**: Tachometer reading from one fan per zone
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- **Auto speed control**: Temperature-based PWM ramping with configurable thresholds
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- **Negative pressure**: Outtake fans run slightly faster for dust control
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- **1.47" LCD display**: Real-time temps, RPMs, and fan duty on Waveshare ST7789
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- **Home Assistant**: Full integration via ESPHome native API
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- **USB-C powered**: 65W PD charger -> ZY12PDN 12V trigger -> fans + ESP32
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## Hardware
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| Component | Qty | Notes |
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|-----------|-----|-------|
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| Waveshare ESP32-C6 LCD 1.47" | 1 | No-touch version, ST7789 172x320 |
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| Arctic P12 PWM 120mm | 6 | 4-pin, 2 per zone |
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| ZY12PDN USB-C PD trigger | 1 | Set to 12V output |
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| LM2596 buck converter | 1 | 12V -> 5V for ESP32 |
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| DS18B20 waterproof probe | 3 | 1m cable, 1-Wire bus |
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| PWM Y-splitter (4-pin) | 3 | 1-to-2 per zone |
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| KF301 screw terminals | 10 | PCB connections |
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| 4.7kOhm resistor | 1 | DS18B20 pull-up |
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| 5x7cm prototype PCB | 1 | Main board |
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## GPIO Mapping (Waveshare ESP32-C6 LCD 1.47")
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### LCD (occupied - do not use)
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| Function | GPIO |
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|----------|------|
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| LCD MOSI | 6 |
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| LCD CLK | 7 |
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| LCD CS | 14 |
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| LCD DC | 15 |
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| LCD RST | 21 |
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| LCD BLK | 22 |
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| RGB LED | 8 |
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| SD MISO | 5 |
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| SD CS | 4 |
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### Project Pin Assignment
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| Function | GPIO | Notes |
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|----------|------|-------|
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| PWM Intake | 0 | Zone 1 - via Y-splitter to 2 fans |
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| PWM Central | 1 | Zone 2 - via Y-splitter to 2 fans |
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| PWM Outtake | 2 | Zone 3 - via Y-splitter to 2 fans |
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| Tach Intake | 3 | RPM from 1 fan in zone 1 |
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| Tach Central | 10 | RPM from 1 fan in zone 2 |
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| Tach Outtake | 11 | RPM from 1 fan in zone 3 |
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| DS18B20 bus | 9 | All 3 sensors on single 1-Wire bus |
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## Wiring Diagram
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```
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USB-C PD Charger (65W+)
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USB-C cable
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v
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ZY12PDN (set to 12V) ----+------ 12V Rail
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v +--- Y-splitter --- Fan1 + Fan2 (INTAKE)
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LM2596 (out=5V) | |
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| +--- Y-splitter --- Fan3 + Fan4 (CENTRAL)
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v | |
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ESP32-C6 (5V in) +--- Y-splitter --- Fan5 + Fan6 (OUTTAKE)
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+-- GPIO0 (PWM) ----> Intake splitter PWM pin
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+-- GPIO1 (PWM) ----> Central splitter PWM pin
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+-- GPIO2 (PWM) ----> Outtake splitter PWM pin
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+-- GPIO3 (TACH) <--- Fan1 tach (yellow wire)
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+-- GPIO10 (TACH) <-- Fan3 tach (yellow wire)
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+-- GPIO11 (TACH) <-- Fan5 tach (yellow wire)
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+-- GPIO9 (1-Wire) --+-- DS18B20 (intake)
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+-- DS18B20 (central)
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+-- DS18B20 (outtake)
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4.7k pull-up to 3.3V
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```
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### 4-Pin Fan Connector Pinout
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```
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Pin 1 (Black) = GND
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Pin 2 (Yellow) = +12V
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Pin 3 (Green) = Tach (RPM signal)
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Pin 4 (Blue) = PWM control
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```
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## Temperature Control Logic
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| Temp Range | Intake | Central | Outtake | Notes |
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|------------|--------|---------|---------|-------|
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| < 28C | 20% | 20% | 25% | Near-silent baseline |
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| 28-35C | 20-50% | 20-50% | 25-55% | Gentle ramp |
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| 35-42C | 50-80% | 50-80% | 55-85% | Medium cooling |
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| 42-50C | 80-100% | 80-100% | 85-100% | Full cooling |
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| > 50C | 100% | 100% | 100% | Emergency + HA alert |
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Outtake always runs +5% over intake for slight negative pressure (dust control).
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## Build & Flash
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```bash
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# Install ESPHome
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pip install esphome
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# Validate config
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esphome config esphome/rack-fan-controller.yaml
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# Flash (first time via USB)
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esphome run esphome/rack-fan-controller.yaml
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# Subsequent updates via OTA
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esphome run esphome/rack-fan-controller.yaml --device rack-fan-ctrl.local
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```
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## Home Assistant
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After flashing, the device auto-discovers in HA via ESPHome integration. Exposed entities:
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- `sensor.rack_temp_intake` / `central` / `outtake`
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- `sensor.rack_fan_rpm_intake` / `central` / `outtake`
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- `sensor.rack_fan_duty_intake` / `central` / `outtake`
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- `switch.rack_fan_auto_mode` (enable/disable auto control)
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- `number.rack_fan_target_temp` (target temperature setpoint)
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- `number.rack_fan_min_duty` / `max_duty` (manual override range)
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## License
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MIT
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