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| 1 | +/* |
| 2 | + Read the temperature pixels from the MLX90640 IR array |
| 3 | + By: Nathan Seidle |
| 4 | + SparkFun Electronics |
| 5 | + Date: May 22nd, 2018 |
| 6 | + License: MIT. See license file for more information but you can |
| 7 | + basically do whatever you want with this code. |
| 8 | +
|
| 9 | + Feel like supporting open source hardware? |
| 10 | + Buy a board from SparkFun! https://www.sparkfun.com/products/14769 |
| 11 | +
|
| 12 | + This example initializes the MLX90640 and outputs the 768 temperature values |
| 13 | + from the 768 pixels. |
| 14 | +
|
| 15 | + This example will work with a Teensy 3.1 and above. The MLX90640 requires some |
| 16 | + hefty calculations and larger arrays. You will need a microcontroller with 20,000 |
| 17 | + bytes or more of RAM. |
| 18 | +
|
| 19 | + This relies on the driver written by Melexis and can be found at: |
| 20 | + https://github.com/melexis/mlx90640-library |
| 21 | +
|
| 22 | + Hardware Connections: |
| 23 | + Connect the SparkFun Qwiic Breadboard Jumper (https://www.sparkfun.com/products/14425) |
| 24 | + to the Qwiic board |
| 25 | + Connect the male pins to the Teensy. The pinouts can be found here: https://www.pjrc.com/teensy/pinout.html |
| 26 | + Open the serial monitor at 9600 baud to see the output |
| 27 | +*/ |
| 28 | + |
| 29 | +#include <Wire.h> |
| 30 | + |
| 31 | +#include "MLX90640_API.h" |
| 32 | +#include "MLX90640_I2C_Driver.h" |
| 33 | + |
| 34 | +const byte MLX90640_address = 0x33; //Default 7-bit unshifted address of the MLX90640 |
| 35 | + |
| 36 | +#define TA_SHIFT 8 //Default shift for MLX90640 in open air |
| 37 | + |
| 38 | +static float mlx90640To[768]; |
| 39 | +paramsMLX90640 mlx90640; |
| 40 | + |
| 41 | +void setup() |
| 42 | +{ |
| 43 | + Wire.begin(); |
| 44 | + Wire.setClock(400000); //Increase I2C clock speed to 400kHz |
| 45 | + |
| 46 | + Serial.begin(9600); |
| 47 | + while (!Serial); //Wait for user to open terminal |
| 48 | + Serial.println("MLX90640 IR Array Example"); |
| 49 | + |
| 50 | + if (isConnected() == false) |
| 51 | + { |
| 52 | + Serial.println("MLX90640 not detected at default I2C addres. Please check wiring. Freezing."); |
| 53 | + while (1); |
| 54 | + } |
| 55 | + Serial.println("MLX90640 online!"); |
| 56 | + |
| 57 | + //Get device parameters - We only have to do this once |
| 58 | + int status; |
| 59 | + uint16_t eeMLX90640[832]; |
| 60 | + status = MLX90640_DumpEE(MLX90640_address, eeMLX90640); |
| 61 | + if (status != 0) |
| 62 | + Serial.println("Failed to load system parameters"); |
| 63 | + |
| 64 | + status = MLX90640_ExtractParameters(eeMLX90640, &mlx90640); |
| 65 | + if (status != 0) |
| 66 | + Serial.println("Parameter extraction failed"); |
| 67 | + |
| 68 | + //Once params are extracted, we can release eeMLX90640 array |
| 69 | +} |
| 70 | + |
| 71 | +void loop() |
| 72 | +{ |
| 73 | + for (byte x = 0 ; x < 2 ; x++) //Read both subpages |
| 74 | + { |
| 75 | + uint16_t mlx90640Frame[834]; |
| 76 | + int status = MLX90640_GetFrameData(MLX90640_address, mlx90640Frame); |
| 77 | + if (status < 0) |
| 78 | + { |
| 79 | + Serial.print("GetFrame Error: "); |
| 80 | + Serial.println(status); |
| 81 | + } |
| 82 | + |
| 83 | + float vdd = MLX90640_GetVdd(mlx90640Frame, &mlx90640); |
| 84 | + float Ta = MLX90640_GetTa(mlx90640Frame, &mlx90640); |
| 85 | + |
| 86 | + float tr = Ta - TA_SHIFT; //Reflected temperature based on the sensor ambient temperature |
| 87 | + float emissivity = 0.95; |
| 88 | + |
| 89 | + MLX90640_CalculateTo(mlx90640Frame, &mlx90640, emissivity, tr, mlx90640To); |
| 90 | + } |
| 91 | + |
| 92 | + for (int x = 0 ; x < 10 ; x++) |
| 93 | + { |
| 94 | + Serial.print("Pixel "); |
| 95 | + Serial.print(x); |
| 96 | + Serial.print(": "); |
| 97 | + Serial.print(mlx90640To[x], 2); |
| 98 | + Serial.print("C"); |
| 99 | + Serial.println(); |
| 100 | + } |
| 101 | + |
| 102 | + delay(1000); |
| 103 | +} |
| 104 | + |
| 105 | +//Returns true if the MLX90640 is detected on the I2C bus |
| 106 | +boolean isConnected() |
| 107 | +{ |
| 108 | + Wire.beginTransmission((uint8_t)MLX90640_address); |
| 109 | + if (Wire.endTransmission() != 0) |
| 110 | + return (false); //Sensor did not ACK |
| 111 | + return (true); |
| 112 | +} |
| 113 | + |
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