The MLX90614 is a non-contact infrared thermometer designed to measure the temperature of objects without requiring direct physical contact. It utilizes advanced infrared sensing technology to provide accurate temperature readings. The sensor outputs temperature data digitally, making it easy to integrate into microcontroller-based systems.
This circuit features an ESP32 microcontroller interfaced with an MLX90614 temperature sensor and an ESP32-CAM module for image capture. The power supply is managed by a 12V battery, a 7805 voltage regulator for 5V, and an AMS1117 regulator for 3.3V, ensuring stable operation of the components.
Open Project in Cirkit Designer
This circuit is a robotic system controlled by an Arduino Mega 2560, which uses multiple sensors including temperature sensors (MLX90614), gas sensors (MQ-136), a GPS module, and a Bluetooth module to navigate and detect environmental conditions. The system drives motors via an L298N motor driver and displays information on a 16x2 I2C LCD, with the ability to receive commands via Bluetooth.
Open Project in Cirkit Designer
This circuit features an ESP32 microcontroller powered by a 18650 Li-Ion battery, with a TP4056 module for charging the battery via a USB plug. The ESP32 reads temperature data from an MLX90614 infrared temperature sensor and displays it on an I2C LCD 16x2 screen. The ESP32, MLX90614 sensor, and LCD screen are connected via I2C communication lines (SCL, SDA), and the circuit is designed to measure and display ambient and object temperatures.
Open Project in Cirkit Designer
This circuit features an ESP32 microcontroller interfaced with an MLX90614 infrared temperature sensor and a 16x2 I2C LCD display for temperature readouts. A tactile button is connected to the ESP32 to trigger temperature measurements, and an LED indicates when a measurement is in progress. The circuit is powered by an 18650 Li-Ion battery, with appropriate resistors for LED current limiting and button debouncing.
Open Project in Cirkit DesignerThe MLX90614 is available in various models, but the following are the general specifications for the most commonly used version:
| Parameter | Value |
|---|---|
| Operating Voltage | 3.6V to 5V |
| Operating Current | 1.5mA (typical) |
| Temperature Range (Object) | -70°C to +380°C |
| Temperature Range (Ambient) | -40°C to +125°C |
| Accuracy | ±0.5°C (typical, for 0°C to +50°C) |
| Communication Protocol | SMBus (I2C compatible) |
| Field of View (FOV) | 35° |
| Resolution | 0.02°C |
The MLX90614 is typically available in a 4-pin TO-39 package. Below is the pinout:
| Pin | Name | Description |
|---|---|---|
| 1 | VDD | Power supply (3.6V to 5V) |
| 2 | VSS | Ground |
| 3 | SDA | Serial Data Line (I2C communication) |
| 4 | SCL | Serial Clock Line (I2C communication) |
0x5A. Ensure no other devices on the I2C bus share this address, or reconfigure the address if necessary.Below is an example of how to interface the MLX90614 with an Arduino UNO using the Adafruit MLX90614 library:
#include <Wire.h>
#include <Adafruit_MLX90614.h>
// Create an instance of the MLX90614 library
Adafruit_MLX90614 mlx = Adafruit_MLX90614();
void setup() {
Serial.begin(9600); // Initialize serial communication at 9600 baud
if (!mlx.begin()) {
Serial.println("Error: MLX90614 not detected. Check wiring!");
while (1); // Halt execution if sensor initialization fails
}
Serial.println("MLX90614 initialized successfully!");
}
void loop() {
// Read object and ambient temperatures
double objectTemp = mlx.readObjectTempC();
double ambientTemp = mlx.readAmbientTempC();
// Print the temperatures to the Serial Monitor
Serial.print("Object Temperature: ");
Serial.print(objectTemp);
Serial.println(" °C");
Serial.print("Ambient Temperature: ");
Serial.print(ambientTemp);
Serial.println(" °C");
delay(1000); // Wait 1 second before the next reading
}
Sensor Not Detected
Inaccurate Temperature Readings
Fluctuating Readings
I2C Address Conflict
Q: Can the MLX90614 measure the temperature of liquids?
A: Yes, but ensure the sensor has a clear line of sight to the liquid's surface and avoid condensation on the sensor.
Q: What is the maximum distance for accurate measurements?
A: The effective range depends on the size of the target and the sensor's field of view. For small objects, the distance should be minimized for accurate readings.
Q: Can I use the MLX90614 with a 3.3V microcontroller?
A: Yes, the MLX90614 operates at 3.6V to 5V, but ensure the I2C lines are properly level-shifted if the microcontroller operates at 3.3V.
Q: How do I change the I2C address of the MLX90614?
A: The I2C address can be changed using specialized software tools and commands. Refer to the sensor's datasheet for detailed instructions.