[OrangePi 4 temperature controlled PWM fan]

Hi all,

 

This is my upgrade. Mean temperature Epoch PWM FAN regulator for Orange Pi 4/4B for Noctua NF-A4x10 5V PWM, Noctua NF-A4x20 5V PWM.

 

$ sudo systemctl status fanepoch
● fanepoch.service - Mean temperature Epoch PWM FAN regulator
     Loaded: loaded (/etc/systemd/system/fanepoch.service; enabled; vendor preset: enabled)
     Active: active (running) since Tue 2021-06-22 21:24:01 CEST; 2min 28s ago
   Main PID: 13074 (epochpwmfan_op4)
      Tasks: 2 (limit: 4459)
     Memory: 516.0K
     CGroup: /system.slice/fanepoch.service
             ├─13074 /bin/bash /usr/local/sbin/epochpwmfan_op4 -e 10
             └─13374 /usr/bin/sleep 10

čen 22 21:25:11 NAS epochpwmfan_op4[13074]: [0]53333 [1]55000 [2]53333 [3]59444 [4]53333 [5]55000 [6]52777
čen 22 21:25:11 NAS epochpwmfan_op4[13074]: Calculate and create RPM list from DutyCycles array
čen 22 21:25:11 NAS epochpwmfan_op4[13074]: RPMLIST[0]: temp 82, duty_cycle 0, rpm 5000
čen 22 21:25:11 NAS epochpwmfan_op4[13074]: RPMLIST[1]: temp 80, duty_cycle 4705, rpm 4415
čen 22 21:25:11 NAS epochpwmfan_op4[13074]: RPMLIST[2]: temp 75, duty_cycle 12549, rpm 3440
čen 22 21:25:11 NAS epochpwmfan_op4[13074]: RPMLIST[3]: temp 65, duty_cycle 20392, rpm 2466
čen 22 21:25:11 NAS epochpwmfan_op4[13074]: RPMLIST[4]: temp 55, duty_cycle 23529, rpm 2062
čen 22 21:25:11 NAS epochpwmfan_op4[13074]: RPMLIST[5]: temp 45, duty_cycle 28235, rpm 1478
čen 22 21:25:11 NAS epochpwmfan_op4[13074]: RPMLIST[6]: temp 0, duty_cycle 32000, rpm 1004
čen 22 21:25:11 NAS epochpwmfan_op4[13074]: temp 51, epoch 54, target 45, duty 28235, rpm 1478

 

Bash script epochpwmfan_op4 with installation instructions in systemd, but also works via init.d, etc...

Spoiler

#!/bin/bash
if [ $# -eq 0 ];
 then
cat << EOF
Mean temperature Epoch PWM FAN regulator for Orange Pi 4/4B - peepr
for Noctua NF-A4x10 5V PWM, Noctua NF-A4x20 5V PWM

Syntax: epochpwmfan_op4 <[-c <N sec> : Classic ||-e <N sec> : Epoch]>

Info: -e Define interval durations between temperature measuring and
 update/control PWM in second.
 One epoch contains 7 intervals. Default interval is 1s.
 Recommended for control PWM with mean Epochs is 3s(= 3x7=21s) to 10s(= 10x7=70s), etc..
 My recommendation is -e 10, ideal for heavy load, at ambient temperature air 21°C
 the CPU temperature will not exceed 62°C.
 
Examples: epochpwmfan_op4 -e 10

Installation instructions: look in the code
EOF
exit 0
fi

#INSTALLATION INSTRUCTIONS:
#sudo cp epochpwmfan_op4 /usr/local/sbin/epochpwmfan_op4
#sudo chmod 755 /usr/local/sbin/epochpwmfan_op4
#sudo geany /etc/systemd/system/fanepoch.service
#--- START ---- insert this line (uncomment!) to fanepoch.service (you can change the switches here according to your preferences in ExecStart)
#[Unit]
#Description=Mean temperature Epoch PWM FAN regulator
#After=syslog.target
#[Service]
#Type=simple
#User=root
#Restart=on-failure
#RestartSec=5s
#ExecStart=/usr/local/sbin/epochpwmfan_op4 -e 10
#[Install]
#WantedBy=multi-user.target
#---  END -----
#sudo chmod 644 /etc/systemd/system/fanepoch.service
#sudo systemctl daemon-reload
#sudo systemctl enable fanepoch
#sudo systemctl start fanepoch
#Check status: sudo systemctl status fanepoch

if [ "$(id -u)" != "0" ]; then
echo "[!] must be root." 1>&2
exit 1
fi

declare -i PERIOD=40000
THA=false #no edit
SLEEPTIME=1 #default
declare -i temp=0
declare -i measuretemp=0

declare -i THAS=6  #temphistory_array_size
THERMAL_ZONE0="/sys/class/thermal/thermal_zone0/temp"

if [ $# -eq 2 ]; then
SLEEPTIME=$2
fi
#activation only with switch -e
if [ "$1" == "-e" ]; then
	THA=true
	declare -a temphistory_array
	declare -i ACTUAL_EPOCH_MEAN_TEMP=0
	echo "Create first Epoch array real temperature - duration $(($SLEEPTIME*(THAS+1))) sec, interval $SLEEPTIME sec"
	for i in $(eval echo "{0..$THAS}");
	do	temphistory_array+=($(cat $THERMAL_ZONE0))
		echo -n "[$i]${temphistory_array[$i]} "
		/usr/bin/sleep $SLEEPTIME
	done
	echo ""
	#Calculation of the actual epoch mean
	ACTUAL_EPOCH_MEAN_TEMP=$(((${temphistory_array[@]/%/+}0)/($THAS+1)))
fi

#Enable PWM regulation
if [ ! -d /sys/class/pwm/pwmchip1/pwm0 ]; then
    echo 0 > /sys/class/pwm/pwmchip1/export
fi

ISENABLE=`cat /sys/class/pwm/pwmchip1/pwm0/enable`
if [ $ISENABLE -eq 1 ]; then
    echo 0 > /sys/class/pwm/pwmchip1/pwm0/enable
fi

# Noctua PWM specification: https://noctua.at/pub/media/wysiwyg/Noctua_PWM_specifications_white_paper.pdf
# Range PWM - minimal: 21kHz (47618ns) to maximum: 28kHz (35714ns). RECOMMENDED is 25kHz (40000ns).
# Convert kHz to ns: https://www.google.com/search?q=period+to+frequency+calculator
echo $PERIOD > /sys/class/pwm/pwmchip1/pwm0/period
echo 1 > /sys/class/pwm/pwmchip1/pwm0/enable

declare -a CpuTemps=(82000 80000 75000 65000 55000 45000 0)

# duty_cycle 40000 = the fan stop. My fan is Noctua NF-A4x10 5V PWM
# - GPIO [yellow cable - +5V in pin2 or pin4, black cable - GND in pin6, blue cable - PWM Signal in pin7]. Look here - run "gpio readall"
# - My fan spins up from off to 38200ns (~250-300rpm) but that can't realistically be used.

declare -a DutyCycles=(0 4705 12549 20392 23529 28235 32000)

#!Calculation formula +- only for Noctua NF-A4x10 5V PWM, Noctua NF-A4x20 5V PWM!
#! - is only but informational and does not control anything					!
echo "Calculate and create RPM list from DutyCycles array" #for speed up script - we avoid infinte counting in a loop :)
declare -a RPMLIST
for i in $(eval echo "{0..$THAS}"); do
 if [ ${DutyCycles[$i]} -ne $PERIOD ]; then 
	RPMLIST[$i]=$(echo "scale=2;5000-((23.2/2)*60)*((${DutyCycles[$i]}/10000)/0.5568)" | bc | cut -d . -f1)
 else
	RPMLIST[$i]=0
 fi
 echo "RPMLIST[$i]: temp $((${CpuTemps[$i]}/1000)), duty_cycle ${DutyCycles[$i]}, rpm ${RPMLIST[$i]}"
done

declare -i LOOPID=0 #max. N = THAS, LOOPID controls the array updates of temperature Epochs
declare -i PREVDUTY=0 #Previous duty_cycle (for comparsion [show rows 133] - we only write a new value, it speeds up the script)
#And we start walking in infinite circles, this part needs to be as fast in running and well thought out as possible :)
while true
do		#Measure real temperature in the thermal_zone0
        measuretemp=$(/usr/bin/cat $THERMAL_ZONE0)
        if  $THA; then
			temp=$ACTUAL_EPOCH_MEAN_TEMP
		else
			temp=$measuretemp
        fi        
        BRK=false
        for i in {0..6}; do
				if [ $BRK == false ] && [ $temp -gt ${CpuTemps[$i]} ]; then
						DUTY=${DutyCycles[$i]}
						#echo "DUTY_CYCLE=$DUTY, PREVDUTY_CYCLE=$PREVDUTY" #debug info
						if [ $PREVDUTY -ne $DUTY ]; then
							echo $DUTY > "/sys/class/pwm/pwmchip1/pwm0/duty_cycle"
							PREVDUTY=$DUTY
							#print info only change fan speed (ideal output for syslog)
							echo "temp $(($measuretemp/1000)), epoch $(($temp/1000)), target $((${CpuTemps[$i]}/1000)), duty $DUTY, rpm ${RPMLIST[$i]}"
						fi						
						#uncomment and comment [rows 137] for print info every interval
						#echo "temp $(($measuretemp/1000)), epoch $(($temp/1000)), target $((${CpuTemps[$i]}/1000)), duty $DUTY, rpm ${RPMLIST[$i]}"
						BRK=true #break
                fi
        done
		if $THA; then
			#echo "LOOPID=$LOOPID" #debug info
			#echo "temphistory_array[$LOOPID] ${temphistory_array[$LOOPID]}" #debug info
			
			#Update "Epoch" array and actual and previous mean
			temphistory_array[$LOOPID]=$measuretemp
			ACTUAL_EPOCH_MEAN_TEMP=$(((${temphistory_array[@]/%/+}0)/($THAS+1)))
			if [ $LOOPID -lt $THAS ]; then
				LOOPID+=1
			else
				LOOPID=0
			fi
		fi
		#loop (measuring) interval: default is 1s [show row 54]
        /usr/bin/sleep $SLEEPTIME
done