Add cpufan script

README.md

@@ -1,2 +1,14 @@
 # fancontrol
-Scripts for controlling the fans on my unraid server
+
+My Unraid server uses an MSI Z97 Gaming 5 Motherboard which I got secondhand. Unfortunately it has a couple of issues:
+
+1. The onboard CPU temperature doesn't work. This means the CPU fan doesn't ramp up when the CPU gets hot.
+2. The lowest the case fans can go down to is 50% using the smart control on the motherboard. This is still quite loud when using Noctua fans as it equates to 800rpm.
+
+I have these scripts to control the fans in my case.
+
+Fans:
+hwmon3/fan2_input - hwmon3/pwm2 - CPU
+hwmon3/fan3_input - hwmon3/pwm3 - Front Bottom
+hwmon3/fan5_input - hwmon3/pwm5 - Front Top (Array fan) - This currently being controlled by the Fan Control Plugin in unraid.
+hwmon3/fan4_input - hwmon3/pwm4 - Rear Exhaust

cpufan.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+# Inspired by https://github.com/kmwoley/unRAID-Tools/blob/master/unraid_array_fan.sh
+
+# User Defined variables
+FAN_LOW_PWM=30
+FAN_HIGH_PWM=255
+FAN_START_PWM=50 # technically 30 but setting higher to ensure fan is running
+LOW_TEMP=28
+HIGH_TEMP=60
+CPU_FAN=/sys/class/hwmon/hwmon3/pwm2
+# End of user defined variables
+
+NUM_STEPS=$((HIGH_TEMP - LOW_TEMP))
+PWM_INCREMENT=$(( (FAN_HIGH_PWM - FAN_LOW_PWM) / NUM_STEPS))
+OUTPUT+="Linear PWM Range is "$FAN_LOW_PWM" to "$FAN_HIGH_PWM" in "$NUM_STEPS" increments of "$PWM_INCREMENT$'\n'
+
+# Enable speed change on this fan if not already
+if [ "$CPU_FAN" != "1" ]; then
+  echo 1 > "${CPU_FAN}_enable"
+fi
+
+PREVIOUS_SPEED=`cat $CPU_FAN`
+
+# TODO: Get from sensors
+CPU_TEMP=30
+
+if [ "$CPU_TEMP" -le "$LOW_TEMP" ]; then 
+  echo $FAN_LOW_PWM  > $CPU_FAN
+  OUTPUT+="Setting pwm to: "$FAN_LOW_PWM$'\n'
+elif [ "$CPU_TEMP" -ge "$HIGH_TEMP" ]; then
+  echo $FAN_HIGH_PWM > $CPU_FAN
+  OUTPUT+="Setting pwm to: "$FAN_HIGH_PWM$'\n'
+else
+  # set fan to starting speed first to make sure it spins up then change it to low setting.
+  if [ "$PREVIOUS_SPEED" -lt "$FAN_START_PWM" ]; then
+    echo $FAN_START_PWM > $CPU_FAN
+      sleep 4
+  fi
+
+  # Calculate target fan PWM speed as a linear value between FAN_HIGH_PWM and FAN_LOW_PWM
+  FAN_LINEAR_PWM=$(( ((CPU_TEMP - LOW_TEMP) * PWM_INCREMENT) + FAN_LOW_PWM))
+  echo $FAN_LINEAR_PWM > $CPU_FAN
+  OUTPUT+="Setting pwm to: "$FAN_LINEAR_PWM$'\n'
+fi
+
+# produce output if the fan speed was changed
+CURRENT_SPEED=`cat $CPU_FAN`
+if [ "$PREVIOUS_SPEED" -ne "$CURRENT_SPEED" ]; then
+  echo "Fan speed has changed."
+  echo "${OUTPUT}"
+else
+  echo "Fan speed unchanged. Highest temp: "$HIGHEST_TEMP" Current pwm: "$CURRENT_SPEED
+fi