I2C Wiring

Use this wiring to connect via I2C interface.

  •  Connect board VIN (red wire) to Arduino 5V if you are running a 5V board Arduino (Uno, etc.). If your board is 3V, connect to that instead.
  • Connect board GND (black wire) to Arduino GND
  • Connect board SCL (yellow wire) to Arduino SCL
  • Connect board SDA (blue wire) to Arduino SDA

The final results should resemble the illustration above, showing an Adafruit Metro development board.

Library Installation

You can install the Adafruit MLX90640 Library for Arduino using the Library Manager in the Arduino IDE.

Click the Manage Libraries... menu item, search for Adafruit MLX90640, and select the Adafruit MLX90640 library:

Then follow the same process for the Adafruit BusIO library.

Finally follow the same process for the Adafruit Unified Sensor library:

Load Example

Open up File -> Examples -> Adafruit MLX90640 -> MLX90640_simpletest and upload to your Arduino wired up to the sensor.

Once you upload the code and open the Serial Monitor (Tools->Serial Monitor) at 115200 baud, you will see an ASCII representation of the thermal camera printed. You should see something similar to this:

Point the thermal camera at objects of differing temperatures to see the ASCII image change!

You also have the option to see the temperatures printed out in a grid. Change the lines below // uncomment *one* of the below to comment out the ASCIIART line and uncomment the TEMPERATURES line so that they match below:

Download: file
// uncomment *one* of the below

Upload the code and open the Serial Monitor (Tools->Serial Monitor) at 115200 baud, and you will see an a grid of temperatures in Celsius printed. To fit the entire grid, you may need to resize the serial monitor window.

Point the thermal camera at objects of differing temperatures to see the printed temperatures change.

#include <Adafruit_MLX90640.h>

Adafruit_MLX90640 mlx;
float frame[32*24]; // buffer for full frame of temperatures

// uncomment *one* of the below

void setup() {
  while (!Serial) delay(10);

  Serial.println("Adafruit MLX90640 Simple Test");
  if (! mlx.begin(MLX90640_I2CADDR_DEFAULT, &Wire)) {
    Serial.println("MLX90640 not found!");
    while (1) delay(10);
  Serial.println("Found Adafruit MLX90640");

  Serial.print("Serial number: ");
  Serial.print(mlx.serialNumber[0], HEX);
  Serial.print(mlx.serialNumber[1], HEX);
  Serial.println(mlx.serialNumber[2], HEX);
  Serial.print("Current mode: ");
  if (mlx.getMode() == MLX90640_CHESS) {
  } else {

  Serial.print("Current resolution: ");
  mlx90640_resolution_t res = mlx.getResolution();
  switch (res) {
    case MLX90640_ADC_16BIT: Serial.println("16 bit"); break;
    case MLX90640_ADC_17BIT: Serial.println("17 bit"); break;
    case MLX90640_ADC_18BIT: Serial.println("18 bit"); break;
    case MLX90640_ADC_19BIT: Serial.println("19 bit"); break;

  Serial.print("Current frame rate: ");
  mlx90640_refreshrate_t rate = mlx.getRefreshRate();
  switch (rate) {
    case MLX90640_0_5_HZ: Serial.println("0.5 Hz"); break;
    case MLX90640_1_HZ: Serial.println("1 Hz"); break; 
    case MLX90640_2_HZ: Serial.println("2 Hz"); break;
    case MLX90640_4_HZ: Serial.println("4 Hz"); break;
    case MLX90640_8_HZ: Serial.println("8 Hz"); break;
    case MLX90640_16_HZ: Serial.println("16 Hz"); break;
    case MLX90640_32_HZ: Serial.println("32 Hz"); break;
    case MLX90640_64_HZ: Serial.println("64 Hz"); break;

void loop() {
  if (mlx.getFrame(frame) != 0) {
  for (uint8_t h=0; h<24; h++) {
    for (uint8_t w=0; w<32; w++) {
      float t = frame[h*32 + w];
      Serial.print(t, 1);
      Serial.print(", ");
      char c = '&';
      if (t < 20) c = ' ';
      else if (t < 23) c = '.';
      else if (t < 25) c = '-';
      else if (t < 27) c = '*';
      else if (t < 29) c = '+';
      else if (t < 31) c = 'x';
      else if (t < 33) c = '%';
      else if (t < 35) c = '#';
      else if (t < 37) c = 'X';
This guide was first published on Jan 29, 2020. It was last updated on Jan 29, 2020. This page (Arduino) was last updated on May 25, 2020.