`surveillance-temperature.sh`

Pine64 PINE A64 / PINE A64+ (Allwinner A64) · File : surveillance-temperature.sh · Language : Bash · Use case : Surveiller la température du processeur et alerter en cas de chauffe

With zero dependencies, this script reads the thermal sensor exposed by the Linux kernel, logs CPU temperature and frequency to CSV and prints an alert past a threshold. Perfect to size passive cooling.

Hardware

A Pine64 (Allwinner A64 quad Cortex-A53, 512 MB-1 GB) running Armbian, connected over Ethernet (the Plus variant adds Wi-Fi). None: the board measures its own temperature (SoC sensor).

Wiring

No wiring. Check /sys/class/thermal/thermal_zone*/temp exists (otherwise load the SoC thermal module).

How it works

The kernel exposes temperature in milli-°C in sysfs; the script converts it, compares with the threshold and appends a timestamped CSV line. The current frequency confirms thermal throttling.

Running it

On Armbian: apt install gpiod python3-gpiod; gpiodetect then gpioinfo to map the expansion header, then run the script.

Variants

Add forced cooling (pwm-fan in sysfs), or push the CSV to a server with curl in the same cron.

surveillance-temperature.sh

#!/bin/bash
# Surveillance thermique : /sys/class/thermal + journalisation + alerte.
# Aucune dependance : sysfs et bash uniquement.

SEUIL_C="${SEUIL_C:-70}"     # degres avant alerte (variable d'env)
INTERVALLE="${INTERVALLE:-5}" # secondes entre deux mesures
JOURNAL="${JOURNAL:-/tmp/cpu-temp.csv}"

[ -f "$JOURNAL" ] || echo "horodatage,temp_c,frequence_mhz" > "$JOURNAL"

# Premier capteur thermique expose par le noyau (varie selon la carte)
ZONE=$(ls /sys/class/thermal/ | grep ^thermal_zone | head -1)
[ -n "$ZONE" ] || { echo "aucun capteur thermique dans /sys/class/thermal"; exit 1; }
echo "Capteur : $ZONE"

while true; do
  TEMP=$(($(cat /sys/class/thermal/$ZONE/temp) / 1000))  # milli-C -> C
  FREQ=$(awk 'NR==1{print $1/1000}' \
        /sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq 2>/dev/null || echo 0)
  TS=$(date -Is)
  echo "$TS,$TEMP,$FREQ" >> "$JOURNAL"
  if [ "$TEMP" -ge "$SEUIL_C" ]; then
    echo "$(date +%T) ALERTE : ${TEMP}C >= ${SEUIL_C}C (freq ${FREQ} MHz)"
  else
    echo "$(date +%T) temp ${TEMP}C  freq ${FREQ}MHz"
  fi
  sleep "$INTERVALLE"
done

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