MLX90614 IR Thermometer Hookup Guide

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Contributors: jimblom
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Evaluation Board Overview

The SparkFun IR Thermometer Evaluation Board wires the MLX90614 up to an ATmega328 microprocessor so you can quickly begin developing with the sensor instead of fussing with wires and breadboards.

Evaluation board product shot

The ATmega328 on the Evaluation Board comes pre-programmed with UART-based example code, and an Arduino bootloader. After monitoring the temperature over the serial interface, you can use that same serial port to upload code of your own!

The Pinout

A pair of headers on opposite sides of the evaluation board break out a handful of microprocessor signals and power busses, and the ATmega's SPI interface is available on the ICSP header:

evaluation board pinout

The pins are all labeled on the bottom side of the board, in case you don't want to refer back to this picture.

Pin LabelEquivalent Arduino PinNotes
Serial Programming/Interface Header
GNDGround (0v)
GNDGround (0v)
VCCVoltage supply input
TX1UART input
RX0UART output
DTRAuto-reset control from FTDI programmer
GPIO/Power Header
3.3V3.3V3.3V supply (regulated from the VCC input)
GNDGNDGround (0v)
PC0A0Analog input and/or digital in/out
PC1A1Analog input and/or digital in/out
PC2A2Analog input and/or digital in/out
PC3A3Analog input and/or digital in/out
SDAA4Serial data line to MLX90614 – more devices can be added to I2C bus.
SCLA5Serial clock to MLX90614 – more devices can be added to I2C bus.
ICSP Header
RSTResetArduino active-low reset
GNDGNDGround (0v)
SCK13SPI clock and/or digital in/out
MOSI11SPI master-out/slave-in and/or digital in/out
MISO12SPI master-in/slave-out and/or digital in/out
VCC3.3V3.3V supply (regulated from the VCC input)

The extra GPIO allow you to build the "Evaluation Board" into a project centerpiece. With seven unused GPIO you can hookup Serial 7-Segment Displays, LCDs, or many other components. Plus, the I2C can be expanded with additional senors -- whether it's a light sensor or a motion sensor.

Example using the MLX90614 Eval board

Wire the MLX90614 Evaluation Board up to a Micro OLED Breakout to create a portable IR Thermometer.

LED Indicators

The evaluation board has a green LED wired up to digital pin 8 (PB0). The LED is active-low, so writing the pin LOW will turn the LED on, and HIGH will turn it off.

The nearby red power LED should illuminate whenever the board is powered.