====== liens ======

    * BCM2835 lib code : http://www.pibits.net/code/raspberry-pi-mlx90614-infrared-thermometer.php
    * http://bildr.org/2011/02/mlx90614-arduino/
    * https://www.raspberrypi.org/forums/viewtopic.php?t=17738
    * S_DATA\electronique\arduino\code\weethermos  contient aussi une petite doc sur les shields utilisé 

      
====== cablage ======
===== mlx90614 =====

  * Part No. MLX90614  [[https://github.com/arduinolearning/Datasheets/blob/master/MLX90614.pdf|datasheet ]]
  * Temperature Code E (-40°C...85°C)    K (-40°C…125°C) 
  * Package Code SF (TO-39) 
  * Option Code - X   X   X   (1) (2) (3) 
    * (1) Supply Voltage/ Accuracy
      *  A  - 5V
      *  B  - 3V
      *  C  - Reserved
      *  D  - 3V medical accuracy 
    * (2) Number of thermopiles:
      *   A – single zone
      *   B – dual zone
      *   C – gradient compensated* 
    * (3) Package options:
      *   A – Standard package
      *   B – Reserved
      *   C – 35° FOV
      *   D/E – Reserved
      *   F – 10° FOV
      *   G – Reserved
      *   H – 12° FOV (refractive lens)
      *    I  – 5° FOV 
  * Standard part -000 
  * Packing form -TU 

{{:divers_elec:mlx90614:temperature_mlxclose.jpg|}}
[[https://learn.adafruit.com/using-melexis-mlx90614-non-contact-sensors/wiring-and-test|source]]

===== Pi =====
WiringPi Pin = WPP
^  Fonction  ^  WPP  ^  Name  ^  Header  ^^  Name  ^  WPP  ^  Fonction  ^
|  mlx90614 pwr  |      |  3.3v   |  1   |  2   |  5v     |      |    |  
|  mlx90614 SDA (pull up on pi board)  |  8   |  SDA    |  3   |  4   |  5v     |      |    |  
|  mlx90614 SCL (pull up on pi board)  |  9   |  SCL    |  5   |  6   |  0v     |      |    |  
|    |  7   |  GPIO7  |  7   |  8   |  TxD    |  15  |    |    
|  mlx90614 gnd  |      |  0v     |  9   |  10  |  RxD    |  16  |    |    
|    |  0   |  GPIO0  |  11  |  12  |  GPIO1  |  1   |    |  
|    |  2   |  GPIO2  |  13  |  14  |  0v     |      |    |    
|    |  3   |  GPIO3  |  15  |  16  |  GPIO4  |  4   |    |  
|    |      |  3.3v   |  17  |  18  |  GPIO5  |  5   |    |  
|    |  12  |  MOSI   |  19  |  20  |  0v     |      |    |
|    |  13  |  MISO   |  21  |  22  |  GPIO6  |  6   |    |  
|    |  14  |  SCLK   |  23  |  24  |  CE0    |  10  |    |  
|    |      |  0v     |  25  |  26  |  CE1    |  11  |    | 

    * https://www.raspberrypi.org/documentation/hardware/raspberrypi/schematics/
      * Pi 3 Model B+ rev 1.0 : 1.8k pull on  SDA SCL (R23 GPIO2) (R24 GPIO3)
      * Pi 3 Model B rev 1.2 : 1.8k pull on  SDA SCL (R23 GPIO2) (R24 GPIO3)
      * Pi 2 Model B rev 1.2 : 1.8k pull on  SDA SCL (R23 GPIO2) (R24 GPIO3)
      * Pi Model B+ rev 1.2 :  1.8k pull on  SDA SCL (R23 GPIO2) (R24 GPIO3)
      * Pi Model A+ rev 1.1 :  1.8k pull on  SDA SCL (R23 GPIO2) (R24 GPIO3)
      * Pi Zero rev 1.3 : 1.8k pull on  SDA SCL (R23 GPIO2) (R24 GPIO3)
      * Pi Zero W rev1.1 : ? pas de BCM2835 sur le schéma ?
===== code =====
<code c>
//gcc mlx90614.c -o mlx90614 -l bcm2835
#include <stdio.h>
#include <bcm2835.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <time.h>
#define AVG 1   //averaging samples
 
# include <termios.h>
	char getch(){
		char buf=0;
		fflush(stdout);
		if(read(0,&buf,1)<0)   perror("read()");
		return buf;
	} 
 
int main(int argc, char **argv)
{
    unsigned char buf[6];
    unsigned char i,reg;
    double temp=0,calc=0, skytemp,atemp,sky_temp_average_double,sky_temp_sum_double=0;
	unsigned int G_nb_sample_uint16=0;
	char c_command;
	
	//pas d'attente et pas d'echo sur getch
	struct termios old={0};
	if(tcgetattr(0, &old)<0) perror("tcsetattr()");
	old.c_lflag&=~ICANON;
	old.c_lflag&=~ECHO;
	old.c_cc[VMIN]=0;
	old.c_cc[VTIME]=0;
	if(tcsetattr(0, TCSANOW, &old)<0) perror("tcsetattr ICANON");
	
    bcm2835_init();
    bcm2835_i2c_begin();
    bcm2835_i2c_set_baudrate(25000);
    // set address
    bcm2835_i2c_setSlaveAddress(0x5a);
    printf("x : exit\nr : RAZ moyenne\nconnected to MLX90614 \n");
 
 while(c_command != 'x')
 { 
     calc=0;
     reg=7;
     for(i=0;i<AVG;i++)
     {
        bcm2835_i2c_begin();
        bcm2835_i2c_write (&reg, 1);
        bcm2835_i2c_read_register_rs(&reg,&buf[0],3);
        temp = (double) (((buf[1]) << 8) + buf[0]);
        temp = (temp * 0.02)-0.01;
        temp = temp - 273.15;
        calc+=temp;
     }
     skytemp=calc/AVG;
    
     calc=0;
     reg=6;
     for(i=0;i<AVG;i++){
        bcm2835_i2c_begin();
        bcm2835_i2c_write (&reg, 1);
        bcm2835_i2c_read_register_rs(&reg,&buf[0],3);
        temp = (double) (((buf[1]) << 8) + buf[0]);
        temp = (temp * 0.02)-0.01;
        temp = temp - 273.15;
        calc+=temp;
     }
    atemp=calc/AVG;
	
    if (c_command == 'r') {sky_temp_sum_double=0; G_nb_sample_uint16=0;}
    sky_temp_sum_double += skytemp;
    G_nb_sample_uint16++;
	sky_temp_average_double = sky_temp_sum_double/G_nb_sample_uint16;
	
    printf("Ambient Temp=%04.2f  Object Temp=%04.2f  Moyenne Object Temp=%04.2f\r", atemp,skytemp,sky_temp_average_double);
	c_command = getch();
    sleep(1);
 }
    //restore setting of getch
    old.c_lflag|=ICANON;
    old.c_lflag|=ECHO;
	if(tcsetattr(0, TCSADRAIN, &old)<0) perror ("tcsetattr ~ICANON");
    printf("\r\n");
    return 0;
}

</code>

====== cablibration ======

<code C>
données
Gris    mlx(IR)     mlx(internal)
20      21.8        21.65
21.8    24.76       24.42
18.5    21.2        19.72
25.6    28.4        26.9
29.2    31.30       31
11      9.6         9.6

amb_temp_f = ((amb_temp_f_ar[0]+amb_temp_f_ar[1]+amb_temp_f_ar[2])/3)-1.6;  //1.6 correctif : moyenne sans MIN et MAX
obj_temp_f = ((obj_temp_f_ar[0]+obj_temp_f_ar[1]+obj_temp_f_ar[2])/3)-2.5;   //2.5 correctif : moyenne sans MIN et MAX

</code>