There is a temperature sensor built into the CPU on your microcontroller board. It reads the internal CPU temperature, which varies depending on how long the board has been running or how intense your code is.
CircuitPython makes it really simple to read this data from the temperature sensor built into the microcontroller. Using the built-in microcontroller module, you can easily read the temperature.
The microcontroller on the Feather RP2040 is located to the right-center of the board, nested between the Adafruit Feather RP2040 label on the silk.
Reading the Microcontroller Temperature
The data is read using two lines of code. All necessary modules are built into CircuitPython, so you don't need to download any extra files to get started.
Connect to the serial console, and then update your code.py to the following.
In the example below, click the Download Project Bundle button below to download the necessary libraries and the code.py file in a zip file. Extract the contents of the zip file, open the directory CircuitPython_Templates/cpu_temperature/ and then click on the directory that matches the version of CircuitPython you're using and copy the contents of that directory to your CIRCUITPY drive.
Your CIRCUITPY drive should now look similar to the following image:
# SPDX-FileCopyrightText: 2021 Kattni Rembor for Adafruit Industries
# SPDX-License-Identifier: MIT
"""CircuitPython CPU temperature example in Celsius"""
import time
import microcontroller
while True:
print(microcontroller.cpu.temperature)
time.sleep(0.15)
The CPU temperature in Celsius is printed out to the serial console!
Try putting your finger on the microcontroller to see the temperature change.
The code is simple. First you import two modules: time and microcontroller. Then, inside the loop, you print the microcontroller CPU temperature, and the time.sleep() slows down the print enough to be readable. That's it!
You can easily print out the temperature in Fahrenheit by adding a little math to your code, using this simple formula: Celsius * (9/5) + 32.
In the example below, click the Download Project Bundle button below to download the necessary libraries and the code.py file in a zip file. Extract the contents of the zip file, open the directory CircuitPython_Templates/cpu_temperature_f/ and then click on the directory that matches the version of CircuitPython you're using and copy the contents of that directory to your CIRCUITPY drive.
Your CIRCUITPY drive should now look similar to the following image:
# SPDX-FileCopyrightText: 2021 Kattni Rembor for Adafruit Industries
# SPDX-License-Identifier: MIT
"""CircuitPython CPU temperature example in Fahrenheit"""
import time
import microcontroller
while True:
print(microcontroller.cpu.temperature * (9 / 5) + 32)
time.sleep(0.15)
The CPU temperature in Fahrenheit is printed out to the serial console!
That's all there is to reading the CPU temperature using CircuitPython!
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