Playground Temperature

But wait! There's more -- the Circuit Playground Express can also tell the temperature!

How, you ask? With a build in thermistor. This little sensor is a thermally sensitive resistor, meaning it's resistance changes based on temperature.

We can access its readings in CircuitPython by importing the adafruit_thermistor library, and then using the board.TEMPERATURE pin to read the thermistor value.

Copy the code below in to a new file, then save it onto the board as main.py. Then, open up a REPL session and you'll see the temperature readings in both Celsius and Fahrenheit. 

# CircuitPlaygroundExpress_Temperature
# reads the on-board temperature sensor and prints the value

import time

import adafruit_thermistor
import board

thermistor = adafruit_thermistor.Thermistor(
    board.TEMPERATURE, 10000, 10000, 25, 3950)

while True:
    temp_c = thermistor.temperature
    temp_f = thermistor.temperature * 9 / 5 + 32
    print("Temperature is: %f C and %f F" % (temp_c, temp_f))

    time.sleep(0.25)

Try placing your finger over the sensor (you'll see a thermometer icon on the board) and watch the readings change.

This guide was first published on Oct 12, 2017. It was last updated on Nov 17, 2018. This page (Playground Temperature) was last updated on Aug 01, 2018.