smarthome-presence-detect/arduino/wärmebildkamera/Example1_BasicReadings/Example1_BasicReadings.ino

/*
  Read the temperature pixels from the MLX90640 IR array
  By: Nathan Seidle
  SparkFun Electronics
  Date: May 22nd, 2018
  License: MIT. See license file for more information but you can
  basically do whatever you want with this code.

  Feel like supporting open source hardware?
  Buy a board from SparkFun! https://www.sparkfun.com/products/14769

  This example initializes the MLX90640 and outputs the 768 temperature values
  from the 768 pixels.

  This example will work with a Teensy 3.1 and above. The MLX90640 requires some
  hefty calculations and larger arrays. You will need a microcontroller with 20,000
  bytes or more of RAM.

  This relies on the driver written by Melexis and can be found at:
  https://github.com/melexis/mlx90640-library

  Hardware Connections:
  Connect the SparkFun Qwiic Breadboard Jumper (https://www.sparkfun.com/products/14425)
  to the Qwiic board
  Connect the male pins to the Teensy. The pinouts can be found here: https://www.pjrc.com/teensy/pinout.html
  Open the serial monitor at 9600 baud to see the output
*/

#include <Wire.h>

#include "MLX90640_API.h"
#include "MLX90640_I2C_Driver.h"

const byte MLX90640_address = 0x33; //Default 7-bit unshifted address of the MLX90640

#define TA_SHIFT 8 //Default shift for MLX90640 in open air

static float mlx90640To[768];
paramsMLX90640 mlx90640;

void setup()
{
  Wire.begin();
  Wire.setClock(100000); //Increase I2C clock speed to 400kHz

  Serial.begin(9600);
  while (!Serial); //Wait for user to open terminal
  Serial.println("MLX90640 IR Array Example");

  if (isConnected() == false)
  {
    Serial.println("MLX90640 not detected at default I2C address. Please check wiring. Freezing.");
    while (1);
  }
  Serial.println("MLX90640 online!");

  //Get device parameters - We only have to do this once
  int status;
  uint16_t eeMLX90640[832];
  status = MLX90640_DumpEE(MLX90640_address, eeMLX90640);
  if (status != 0)
    Serial.println("Failed to load system parameters");

  status = MLX90640_ExtractParameters(eeMLX90640, &mlx90640);
  if (status != 0)
    Serial.println("Parameter extraction failed");

  //Once params are extracted, we can release eeMLX90640 array
}

void loop()
{
  for (byte x = 0 ; x < 2 ; x++) //Read both subpages
  {
    uint16_t mlx90640Frame[834];
    int status = MLX90640_GetFrameData(MLX90640_address, mlx90640Frame);
    if (status < 0)
    {
      Serial.print("GetFrame Error: ");
      Serial.println(status);
    }

    float vdd = MLX90640_GetVdd(mlx90640Frame, &mlx90640);
    float Ta = MLX90640_GetTa(mlx90640Frame, &mlx90640);

    float tr = Ta - TA_SHIFT; //Reflected temperature based on the sensor ambient temperature
    float emissivity = 0.95;

    MLX90640_CalculateTo(mlx90640Frame, &mlx90640, emissivity, tr, mlx90640To);
  }

  for (int x = 0 ; x < 10 ; x++)
  {
    Serial.print("Pixel ");
    Serial.print(x);
    Serial.print(": ");
    Serial.print(mlx90640To[x], 2);
    Serial.print("C");
    Serial.println();
  }

  delay(1000);
}

//Returns true if the MLX90640 is detected on the I2C bus
boolean isConnected()
{
  Wire.beginTransmission((uint8_t)MLX90640_address);
  if (Wire.endTransmission() != 0)
    return (false); //Sensor did not ACK
  return (true);
}