The MLX90614 is a non-contact infrared temperature sensor designed to measure the temperature of objects without requiring direct physical contact. It utilizes advanced infrared technology to provide accurate temperature readings over a wide range. This sensor is widely used in applications such as temperature monitoring, medical devices (e.g., thermometers), HVAC systems, and industrial automation. Its ability to measure both object and ambient temperatures makes it a versatile and reliable component for various projects.
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 different models, but the following are the general technical specifications for the most commonly used version:
The MLX90614 typically comes with four pins. The table below describes each pin:
| Pin | Name | Description |
|---|---|---|
| 1 | VDD | Power supply input (3.6V to 5V DC) |
| 2 | VSS | Ground (0V) |
| 3 | SDA | Serial Data Line for I²C communication |
| 4 | SCL | Serial Clock Line for I²C communication |
Adafruit_MLX90614).Below is an example of how to use the MLX90614 with an Arduino UNO to read object and ambient temperatures:
#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
Serial.println("MLX90614 Temperature Sensor Test");
if (!mlx.begin()) {
Serial.println("Error: Could not find a valid MLX90614 sensor!");
while (1); // Halt execution if sensor initialization fails
}
}
void loop() {
// Read object temperature in Celsius
float objectTemp = mlx.readObjectTempC();
// Read ambient temperature in Celsius
float ambientTemp = mlx.readAmbientTempC();
// Print the readings 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 for 1 second before taking the next reading
}
Sensor Not Detected:
Inaccurate Temperature Readings:
Interference on I²C Lines:
Q1: Can the MLX90614 measure the temperature of liquids?
A1: Yes, the MLX90614 can measure the temperature of liquids as long as the liquid's surface is within the sensor's field of view and there is no obstruction.
Q2: What is the maximum distance for accurate temperature measurement?
A2: The effective distance depends on the size of the object and the sensor's field of view. For small objects, the sensor should be placed closer for accurate readings.
Q3: Can I use the MLX90614 with a 3.3V microcontroller?
A3: Yes, the MLX90614 is compatible with 3.3V systems. Ensure that the pull-up resistors on the I²C lines are appropriate for 3.3V operation.
Q4: How do I switch between Celsius and Fahrenheit?
A4: The MLX90614 outputs temperature in Celsius by default. You can convert it to Fahrenheit in your code using the formula:
Fahrenheit = (Celsius * 9/5) + 32.
By following this documentation, you can effectively integrate the MLX90614 into your projects and troubleshoot common issues.