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A Hello World program showing how to get temperature readings from the MLX90614 infrared temperature sensor.
main.cpp@0:964606fa7e7a, 2016-05-11 (annotated)
- Committer:
- jjones646
- Date:
- Wed May 11 17:48:57 2016 +0000
- Revision:
- 0:964606fa7e7a
Adding example program for the MLX90614 temperature sensor.
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
jjones646 | 0:964606fa7e7a | 1 | /* |
jjones646 | 0:964606fa7e7a | 2 | * Example program showing how to get the temperature readings from |
jjones646 | 0:964606fa7e7a | 3 | * an MLX90614 infrared temperature sensor using an mbed. |
jjones646 | 0:964606fa7e7a | 4 | * http://www.haoyuelectronics.com/Attachment/GY-906/MLX90614.pdf |
jjones646 | 0:964606fa7e7a | 5 | * |
jjones646 | 0:964606fa7e7a | 6 | * Jonathan Jones |
jjones646 | 0:964606fa7e7a | 7 | */ |
jjones646 | 0:964606fa7e7a | 8 | |
jjones646 | 0:964606fa7e7a | 9 | #include "mbed.h" |
jjones646 | 0:964606fa7e7a | 10 | #include "gy-906.h" |
jjones646 | 0:964606fa7e7a | 11 | |
jjones646 | 0:964606fa7e7a | 12 | using namespace gy906; |
jjones646 | 0:964606fa7e7a | 13 | |
jjones646 | 0:964606fa7e7a | 14 | I2C i2c(p9, p10); |
jjones646 | 0:964606fa7e7a | 15 | const uint8_t addr = default_addr; |
jjones646 | 0:964606fa7e7a | 16 | |
jjones646 | 0:964606fa7e7a | 17 | // kelvin to fahrenheit |
jjones646 | 0:964606fa7e7a | 18 | float k2f(float raw_kelvin) |
jjones646 | 0:964606fa7e7a | 19 | { |
jjones646 | 0:964606fa7e7a | 20 | return (raw_kelvin - 273.15) * 1.8 + 32; |
jjones646 | 0:964606fa7e7a | 21 | } |
jjones646 | 0:964606fa7e7a | 22 | |
jjones646 | 0:964606fa7e7a | 23 | // read and return one of the temperature regs |
jjones646 | 0:964606fa7e7a | 24 | float get_temp(uint8_t reg) { |
jjones646 | 0:964606fa7e7a | 25 | char cmd[3] = { 0 }; |
jjones646 | 0:964606fa7e7a | 26 | // read the temperature data (kelvin) |
jjones646 | 0:964606fa7e7a | 27 | cmd[0] = opcode::ram_access | reg; |
jjones646 | 0:964606fa7e7a | 28 | i2c.write(addr,cmd,1,true); i2c.read(addr,cmd,3); |
jjones646 | 0:964606fa7e7a | 29 | // convert to meaningful units, still in kelvin - just normalized |
jjones646 | 0:964606fa7e7a | 30 | return 0.02 * static_cast<float>((cmd[1]<<8)|cmd[0]); |
jjones646 | 0:964606fa7e7a | 31 | } |
jjones646 | 0:964606fa7e7a | 32 | |
jjones646 | 0:964606fa7e7a | 33 | int main() { |
jjones646 | 0:964606fa7e7a | 34 | uint8_t reg_addrs[] = { ram::T_ambient, ram::T_obj1 }; |
jjones646 | 0:964606fa7e7a | 35 | float tt = 0.0; |
jjones646 | 0:964606fa7e7a | 36 | // clear terminal & hide cursor |
jjones646 | 0:964606fa7e7a | 37 | printf("\033[r\033[2J\033[?25l"); fflush(stdout); |
jjones646 | 0:964606fa7e7a | 38 | while (true) { |
jjones646 | 0:964606fa7e7a | 39 | for (size_t i = 0; i < sizeof(reg_addrs); ++i) { |
jjones646 | 0:964606fa7e7a | 40 | tt = get_temp(reg_addrs[i]); |
jjones646 | 0:964606fa7e7a | 41 | printf("\r\033[KT%u:\t%.2f°F\r\n", i, k2f(tt)); |
jjones646 | 0:964606fa7e7a | 42 | fflush(stdout); |
jjones646 | 0:964606fa7e7a | 43 | } |
jjones646 | 0:964606fa7e7a | 44 | wait(0.1); |
jjones646 | 0:964606fa7e7a | 45 | printf("\033[%uA", sizeof(reg_addrs)); fflush(stdout); |
jjones646 | 0:964606fa7e7a | 46 | } |
jjones646 | 0:964606fa7e7a | 47 | } |