- 3D Print a Base for Your RPi and Pi-Plate
- LAN/WiFi Speaker Switch
- Solar Powered Remote Environmental Data Logger
- Raspberry Pi HQ Camera Mount
- Using a THERMOplate to Measure Temperatures on the RPi4
- Making Sparks with Pi-Plates
- Dual Syringe Pump
- Cigarbox Pi
- Benchmarking the Pi 3
- Turn Your Raspberry Pi into a Network Monitoring Tool
- Using Pi-Plates with the Raspberry Pi 400
There have already been a few reviews showing very pretty thermal images of the Raspberry Pi 4. While that's a quick way to collect approximate temperature data, we prefer to do it the old fashioned way using discrete thermocouples. So, this post describes how we used a Pi-Plates THERMOplate on a Pi 3 Model B+, to capture the temperature rise on four different components on a Pi 4 with 1Gbyte of RAM.
The THERMOplate is a 12 channel board for the Raspberry Pi that supports eight K Type thermocouples and four DS18B20 digital sensors. For this evaluation, we used kapton tape to run thermocouples to the following points on the RPi4:
- Power Supply
- Radio
- CPU
- RAM
- Ambient Air
Sensor Locations
Using our DATAlogger program, we collected the data from each of the thermocouples at a rate of 1 sample/second for a total of 10 minutes. Shortly after initiating the log, we launched a benchmarking program from the command line of the RPi4 to start calculating prime numbers in each of the four cores:
pi@RPi4:~$ sysbench --test=cpu --cpu-max-prime=20000 --num-threads=4 --max-requests=1000000 run
And, it didn't take long before red lines started appearing in the little CPU temperature monitor we had running on the taskbar:
It appeared to us that when the CPU temperature starts to hit 80°C, the RPi throttles back although there have been others who state the threshold is 85°C.
A plot of the results is shown below:
RPi4 Component Temperatures During Benchmark Testing
We then averaged the last 200 samples to get these values:
| Location | Idle Temperature | Benchmark Temperature | Temperature Rise above Ambient |
|---|---|---|---|
| Power IC | 48.93 | 55.81 | 28.49 |
| Radio Shield | 50.18 | 58.22 | 30.89 |
| CPU | 54.67 | 65.79 | 38.47 |
| RAM | 51.96 | 59.21 | 31.89 |
| Ambient | 27.32 | 27.32 | NA |
Conclusions:
- Yes, the RPi4 gets warm but the designers have taken steps to avoid overheating: the CPU will throttle back if it gets too hot and there is ample copper (and vias that are hot to the touch) located under those components that generate heat such as the Power IC.
- Examination of the CPU temperature plot shows a small amount of ripple - we suspect this is from the the CPU dropping in and out of throttle mode.