[arm-allstar] Temperature Based Fan Script

[Doug Crompton]

Mike,

 Easy enough to do, Here is a script that combines temperature and a delay
based on TX.  Of course this can be modified to your liking. There is lots
of feedback so if you run this manually you will see what is happening. I
would recommend lengthening the overall delay to maybe 5 seconds at the end
after testing. The delay could be set to whatever you want  - 0 seconds to
minutes.


*73 Doug*

*WA3DSP*

*http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*

#!/bin/bash
# Script to check for PTT and turn on fan via GPIO
# D. Crompton WA3DSP 11/2018

# This script incorporates CPU temperature

# Make sure the events stanza is named properly
# The node stanza will have an events=enventsxxxxx
# where xxxxx is the node number. Replace the
# xxxxx with the node number below
# Add the following three lines to rpt.conf

# [eventsxxxxx]
# touch /tmp/RPT_TXXKEYED = s|t|RPT_TXKEYED
# rm -f /tmp/RPT_TXKEYED = s|f|RPT_TXKEYED

# TX Key file check
TXKEYED="/tmp/RPT_TXKEYED"

# Fan delay at unkey - Seconds or Xm minutes
fan_delay="5"

# GPIO fan control pin
# GPIO.23 Pi Physical pin 33

FAN_BIT=23

# Max CPU temperature in C
MAX_TEMP=50

function get_cpu_temp {

PTEMP=`cat /sys/class/thermal/thermal_zone0/temp`
PTEMP=`expr $PTEMP / 1000`
echo "CPU Temp - $PTEMP"

}

function FAN_ON {

# Turn on Fan
gpio write $FAN_BIT 1
echo "Fan ON"

while [ -e $TXKEYED ]
do
   sleep 1
done
echo "Waiting Fan Delay"
sleep $fan_delay

}

gpio mode $FAN_BIT out

while :
do
if [ -e  $TXKEYED ]
  then
    echo "TX"
    FAN_ON

  else
    echo "NO TX"
    # turn fan off
    get_cpu_temp
    if [ $PTEMP -lt $MAX_TEMP ]
      then
      echo "Fan Below Max Temperature - Fan OFF"
          gpio write $FAN_BIT 0
      else
          echo "CPU over temperature - Fan remains ON"
          FAN_ON
    fi
fi
sleep 1
done



On Sat, Dec 1, 2018 at 3:44 PM "Mike Besemer via ARM-allstar" <
arm-allstar at hamvoip.org> wrote:

> Has anyone written a fan control script based on CPU temperature?  Ideally,
> I'd like to have a script that could monitor the CPU temperature and run
> the
> fan when the CPU exceeds a certain (user setable)  setpoint.
>
> I saw the script that Doug wrote to control the fan based on PTT but one of
> my Pi's needs intermittent cooling to keep the CPU below 50C regardless of
> PTT activity.
>
> 73,
>
> Mike
> WM4B
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