How to Check CPU Temperature and Usage on Raspberry Pi?

Monitoring your Raspberry Pi's CPU temperature and usage helps prevent overheating and optimize performance. Here are the best methods:

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1. Check CPU Temperature

Method 1: vcgencmd (Built-in Command)

bash

vcgencmd measure_temp

Example Output:

text

temp=45.6'C

Method 2: Read from /sys/class/thermal

bash

cat /sys/class/thermal/thermal_zone0/temp | awk '{printf "%.1f°C\n", $1/1000}'

Example Output:

text

47.2°C

Method 3: Install sensors (for Advanced Monitoring)

bash

sudo apt install lm-sensors
sensors

(Note: May require additional configuration for RPi.)

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2. Check CPU Usage

Method 1: top (Real-Time Monitoring)

bash

top

• Press q to exit.

• Look for %Cpu(s) at the top.

Method 2: htop (Enhanced Version)

bash

sudo apt install htop
htop

• Shows per-core usage in color.

• Press F10 to exit.

Method 3: mpstat (Detailed Stats)

bash

sudo apt install sysstat
mpstat 1  # Updates every second

Example Output:

text

%usr %nice %sys %iowait %irq %soft %steal %idle  
20.1  0.0   3.2   1.5    0.0   0.1    0.0   75.1

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3. Automated Monitoring (Logging & Alerts)

Log Temperature to a File

bash

while true; do vcgencmd measure_temp >> cpu_temp.log; sleep 5; done

(Runs every 5 seconds. Stop with Ctrl+C.)

Set Up High-Temp Alerts

bash

#!/bin/bash
TEMP=$(vcgencmd measure_temp | cut -d= -f2 | cut -d\' -f1)
if (( $(echo "$TEMP > 80" | bc -l) )); then
  echo "Warning: High CPU temperature! ($TEMP°C)" | mail -s "RPi Overheat Alert" your@email.com
fi

(Run as a cron job every few minutes.)

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4. GUI Tools (For Desktop Users)

RPi-Monitor (Web Dashboard)

bash

sudo apt install raspimon

• Access via http://your-pi-ip:8888

Conky (Desktop Widget)

bash

sudo apt install conky
conky

(Displays CPU temp, usage, RAM, and more.)

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5. Safe Temperature Ranges for Raspberry Pi

(Throttling starts at 80°C*; Pi may shut down at **85°C**.)*

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Cooling Tips for Raspberry Pi

• Passive Cooling: Use a heatsink (works for light loads).

• Active Cooling: Add a 5V fan (GPIO-powered or USB).

• Case Ventilation: Ensure proper airflow in the enclosure.

• Undervolting: (Advanced) Reduce power usage with vcgencmd.

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Final Thoughts

• For quick checks: Use vcgencmd measure_temp and htop.

• For long-term logging: Use cron jobs + email alerts.

• For overheating issues: Improve cooling and check background processes (top).