The Raspberry Pi Pico comes with a built-in temperature sensor connected to ADC4. In this quick guide, you’ll learn how to get temperature data from that sensor using Arduino IDE.

New to the Raspberry Pi Pico? Read the following guide: Getting Started with Raspberry Pi Pico (and Pico W).

Prerequisites

You need to install the Raspberry Pi Pico boards on Arduino IDE and you must know how to upload code to the board. Check out the following tutorial first if you haven’t already:

• Programming Raspberry Pi Pico with Arduino IDE

The Internal Temperature Sensor

The Raspberry Pi Pico internal temperature sensor works by checking the voltage of a special diode connected to ADC4 on the Raspberry Pi Pico.

Accurate temperature measurements with this sensor can be challenging. Consider it more as a reference tool than a precise measurement device.

Reading the Temperature using ADC

To read the Raspberry Pi Pico internal temperature sensor using Arduino IDE, you can use the analogReadTemp() function that returns the temperature in Celsius degrees.

You can use the following code to test it. This code prints the temperature in Celsius and Fahrenheit degrees to the Serial Monitor.

/*********
  Rui Santos & Sara Santos - Random Nerd Tutorials
  Complete project details at https://RandomNerdTutorials.com/raspberry-pi-pico-internal-temperature-arduino/
*********/

float tempC;
float tempF;

void setup() {
  Serial.begin(115200);
}

void loop() {
  tempC = analogReadTemp(); // Get internal temperature
  tempF = tempC * 9.0 / 5.0 + 32.0; // Fahrenheit conversion
  Serial.print("Temperature Celsius (ºC): ");
  Serial.println(tempC);
  Serial.print("Temperature Fahrenheit (ºF): ");
  Serial.println(tempF);
  delay(1000);
}

View raw code

How the Code Works

Let’s take a quick look at how the code works.

Recommended reading: Raspberry Pi Pico: Read Analog Inputs (Arduino IDE)

Initializing variables

Start by creating two variables tempC, and tempF to hold the temperature values in Celsius and Fahrenheit degrees.

float tempC;
float tempF;

Initialize the Serial Monitor

In the setup(), initialize the Serial Monitor at a baud rate of 115200

void setup() {
  Serial.begin(115200);
}

Get and Print the Temperature

We get the Raspberry Pi Pico internal temperature sensor in Celsius degrees by using the analogReadTemp() function.

tempC = analogReadTemp(); // Get internal temperature

Then, we convert the temperature in Celsius to Fahrenheit degrees.

tempF = tempC * 9.0 / 5.0 + 32.0; // Fahrenheit conversion

Finally, we print the readings in the Serial Monitor.

Serial.print("Temperature Celsius (ºC): ");
Serial.println(tempC);
Serial.print("Temperature Fahrenheit (ºF): ");
Serial.println(tempF);

The readings are printed every second (1000 milliseconds).

delay(1000);

Testing the Code

Upload the code to the Raspberry Pi Pico. Don’t know how to upload code? Check this tutorial: Programming Raspberry Pi Pico with Arduino IDE.

Open the Serial Monitor at a baud rate of 115200.

New temperature readings in Celsius and Fahrenheit degrees will be printed in the Serial Monitor every second.

Wrapping Up

The Raspberry Pi Pico comes with an internal temperature sensor to give you a general idea of the Pico’s internal temperature.

Reading the Pico’s temperature using Arduino IDE is as easy as using the analogReadTemp() function. You may take this project further and display the temperature on an OLED display: Raspberry Pi Pico: SSD1306 OLED Display (Arduino IDE).

We hope you’ve found this tutorial useful. If you’re just getting started with the Raspberry Pi Pico, you might also like the following tutorials:

• Raspberry Pi Pico: Read Analog Inputs (Arduino IDE)
• Raspberry Pi Pico: Control Digital Outputs and Read Digital Inputs (Arduino IDE)
• Raspberry Pi Pico: Fading an LED using PWM (Arduino IDE)

Learn more about the Raspberry Pi Pico with our resources:

• Raspberry Pi Pico Projects and Guides
• Learn Raspberry Pi Pico with MicroPython eBook

Thanks for reading.