main.cpp

00001 /*
00002  * Example program showing how to get the temperature readings from
00003  * an MLX90614 infrared temperature sensor using an mbed.
00004  * http://www.haoyuelectronics.com/Attachment/GY-906/MLX90614.pdf
00005  *
00006  * Jonathan Jones
00007  */
00008 
00009 #include "mbed.h"
00010 #include "gy-906.h"
00011 
00012 using namespace gy906;
00013 
00014 I2C i2c(p9, p10);
00015 const uint8_t addr = default_addr;
00016 
00017 // kelvin to fahrenheit
00018 float k2f(float raw_kelvin)
00019 {
00020     return (raw_kelvin - 273.15) * 1.8 + 32;
00021 }
00022 
00023 // read and return one of the temperature regs
00024 float get_temp(uint8_t reg) {
00025     char cmd[3] = { 0 };
00026     // read the temperature data (kelvin)
00027     cmd[0] = opcode::ram_access | reg;
00028     i2c.write(addr,cmd,1,true); i2c.read(addr,cmd,3);
00029     // convert to meaningful units, still in kelvin - just normalized
00030     return 0.02 * static_cast<float>((cmd[1]<<8)|cmd[0]);
00031 }
00032 
00033 int main() {
00034     uint8_t reg_addrs[] = { ram::T_ambient, ram::T_obj1 };
00035     float tt = 0.0;
00036     // clear terminal & hide cursor
00037     printf("\033[r\033[2J\033[?25l"); fflush(stdout);
00038     while (true) {
00039         for (size_t i = 0; i < sizeof(reg_addrs); ++i) {
00040             tt = get_temp(reg_addrs[i]);
00041             printf("\r\033[KT%u:\t%.2f°F\r\n", i, k2f(tt));
00042             fflush(stdout);
00043         }
00044         wait(0.1);
00045         printf("\033[%uA", sizeof(reg_addrs)); fflush(stdout);
00046     }
00047 }