KevsRobots Learning Platform

Using the Raspberry Pi Pico's Built-in Temperature Sensor

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Introduction to the Raspberry Pi Pico and MicroPython
Understanding the Built-in Temperature Sensor
Writing Your First Temperature Sensor Script
Enhancing Your Temperature Monitoring Project
Project Challenges and Next Steps

Converting ADC Values to Temperature

Learn how to convert raw ADC values from the temperature sensor into human-readable temperatures in degrees Celsius.

By Kevin McAleer,    2 Minutes

Introduction

Raw ADC values aren’t particularly useful on their own. This lesson will show you how to use a formula to convert the ADC value into a temperature in degrees Celsius.

The Conversion Formula

The Pico’s temperature sensor uses the following formula to calculate temperature in degrees Celsius:

temperature = 27 - (raw_value - 0.706) / 0.001721

Step 1: Updating Your Script

Modify your previous script to include the temperature calculation:

import machine
import time

# Initialize the ADC for the temperature sensor
sensor_adc = machine.ADC(4)

while True:
    # Read the raw ADC value
    raw_value = sensor_adc.read_u16()
    
    # Convert the ADC value to voltage
    voltage = raw_value * 3.3 / 65535

    # Convert voltage to temperature
    temperature = 27 - (voltage - 0.706) / 0.001721

    print(f"Temperature: {temperature:.2f}°C")
    time.sleep(1)

Step 2: Running the Script

  1. Save the updated script as read_temp_with_conversion.py.
  2. Run the script in Thonny.
  3. Observe the temperature readings displayed in degrees Celsius.

What You’ve Learned

  • How to use the conversion formula to calculate temperature.
  • How to display formatted output in the console.

In the next lesson, you’ll learn how to format and enhance the output for better readability.

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