RPi.fanspeed

Adjustable fanspeed with temperature and RPM monitoring for MQTT

Requirements

• raspberry pi
• python 3.7
• pigpio
• paho-mqtt (only if MQTT is used)

Installation

Edit config.sh and run setup.sh... The installation method can be set to show command line or install service.

Configuration

The fan must be connected to one of the hardware PWM pins (12, 13, 18, 19 for RPi3B+) The service can be configured in /etc/systemd/system/raspi_fanspeed.service using the command line arguments.

The RPM sginal can be connected to any GPIO pin.

The fan can be configured to run from 30-90°C with increasing speed. For example starting at 50°C with 30% PWM duty cycle and increasing the level up to 100% till reaching 75°C

# raspi_fanspeed --min 50 --max=75 --min-fan=30 -S
{
  "0.0%": "30.0°C",
  "30.0%": "50.0°C",
  "32.8%": "51.0°C",
  "35.6%": "52.0°C",
  "38.4%": "53.0°C",
  "41.2%": "54.0°C",
  "44.0%": "55.0°C",
  "46.8%": "56.0°C",
  "49.6%": "57.0°C",
  "52.4%": "58.0°C",
  "55.2%": "59.0°C",
  "58.0%": "60.0°C",
  "60.8%": "61.0°C",
  "63.6%": "62.0°C",
  "66.4%": "63.0°C",
  "69.2%": "64.0°C",
  "72.0%": "65.0°C",
  "74.8%": "66.0°C",
  "77.6%": "67.0°C",
  "80.4%": "68.0°C",
  "83.2%": "69.0°C",
  "86.0%": "70.0°C",
  "88.8%": "71.0°C",
  "91.6%": "72.0°C",
  "94.4%": "73.0°C",
  "97.2%": "74.0°C",
  "100.0%": "75.0°C"
}

Temperature

The temperature is read from sys/class/thermal/thermal_zone0/temp by default.

MQTT and homeassistant

When the service is running with MQTT enabled, it pushes the temperature and fan speed in intervals to topic home/{device_name}/RPi.fanspeed/json. device_name is the hostname by default.

The home assistant auto discovery prefix is set to homeassistant and 3 sensors should show up after starting the service.

CLI

# raspi_fanspeed -h
usage: raspi_fanspeed [-h] [-i INTERVAL] [--set SET] [--measure MEASURE]
                      [--min MIN] [--max MAX] [--lin LIN] [--min-fan MIN_FAN]
                      [-p {12,13,18,19}] [--rpm-pin RPM_PIN] [-f FREQUENCY]
                      [-S] [-E ONEXIT_SPEED] [--mqttuser MQTTUSER]
                      [--mqttpass MQTTPASS] [--mqttdevicename MQTTDEVICENAME]
                      [--mqtttopic MQTTTOPIC] [--mqtthass MQTTHASS]
                      [--mqttupdateinterval MQTTUPDATEINTERVAL] [-H MQTTHOST]
                      [-P MQTTPORT] [-L LOG] [-V] [-v] [--pid PID]

adjustable fanspeed with temperature monitoring

optional arguments:
  -h, --help            show this help message and exit
  -i INTERVAL, --interval INTERVAL
                        fan speed update interval in seconds
  --set SET             set speed in %
  --measure MEASURE     measure rpm for n seconds and exit
  --min MIN             minimum temperature to turn on fan in °C
  --max MAX             maximum fan speed if temperature exceeds this value
  --lin LIN             temperature/duty cycle factor. 1.0 = linear
  --min-fan MIN_FAN     minimum fan speed in %
  -p {12,13,18,19}, --pin {12,13,18,19}
                        fan PWM pin. must be capable of hardware PWM
  --rpm-pin RPM_PIN     read RPM signal from pin
  -f FREQUENCY, --frequency FREQUENCY
                        PWM frequency
  -S, --print-speed     Print fan speed table and exit
  -E ONEXIT_SPEED, --onexit-speed ONEXIT_SPEED
                        turn fan to 30-100% when exiting. -1 disable fan on
                        exit
  --mqttuser MQTTUSER   use phyton mqtt client to connect to MQTT
  --mqttpass MQTTPASS
  --mqttdevicename MQTTDEVICENAME
                        mqtt device name
  --mqtttopic MQTTTOPIC
  --mqtthass MQTTHASS
  --mqttupdateinterval MQTTUPDATEINTERVAL
                        mqtt update interval (30-900 seconds)
  -H MQTTHOST, --mqtthost MQTTHOST
  -P MQTTPORT, --mqttport MQTTPORT
  -L LOG, --log LOG     write temperature and speed to this file i.e.
                        --log=/var/log/tempmon.json
  -V, --version
  -v, --verbose
  --pid PID