Rockpro64 CPU fan

[seandepagnier]

I have speed control adding to crontab:

* * * * * fancontrol.py

Code:

#!/usr/bin/python

import os

def write_fan(pwm):
   try:
       f = open('/sys/devices/platform/pwm-fan/hwmon/hwmon0/pwm1', 'w')
       f.write("%d" % pwm)
   except:
       print 'failed to write fan'

def read_temp():
   try:
       f = open('/sys/devices/virtual/thermal/thermal_zone0/temp')
       return float(f.readline())/1000.0
   except:
       print 'failed to read temperature'
       return 80


t = read_temp()

# cut on at 58C
speed = min(int(10*(t - 58) + 120), 255)
if speed < 120:
   speed = 0

write_fan(speed)

It only cuts on if I am compiling something or using a lot of cpu.  Normally using conservative governor with 408mhz.   I have the large heatsink (designed for not fan) but I have a fan anyway.

The fan does not run very fast even at full speed.   It is a 12v fan.  I didn't measure the voltage powering it, I suspect it only gets 5 volts even at max speed.