MLX90614 Non-Contact IR Temperature Sensor

The MLX90614 is a Contactless Infrared (IR) Digital Temperature Sensor that can be used to measure the temperature of a particular object ranging from -70° C to 382.2°C. The sensor uses IR rays to measure the temperature of the object without any physical contact and communicates to the microcontroller using the I2C protocol.

 

MLX90614 Pinout Configuration

Pin No.	Pin Name	Description
1	Vdd (Power supply)	Vdd can be used to power the sensor, typically using 5V
2	Ground	The metal can also act as ground
3	SDA – Serial Data	Serial data pin used for I2C Communication
4	SCL – Serial Clock	Serial Clock Pin used for I2C Communication

 

MLX90614 Temperature Sensor Specifications

• Operating Voltage: 3.6V to 5V (available in 3V and 5V version)
• Supply Current: 1.5mA
• Object Temperature Range: -70° C to 382.2°C
• Ambient Temperature Range: -40° C to 125°C
• Accuracy: 0.02°C
• Field of View: 80°
• Distance between object and sensor: 2cm-5cm (approx.)

 

Note: More Technical details about the MLX90614 sensor can be found in the MLX90614 datasheet linked at the bottom of this page.

 

Alternative for MLX90614: MLX90615, ZTP115, TPIS 1S

Alternate Ambient Temperature Sensors: DHT11, DHT22, PT100, TMP36, DS18B20

 

Where to use the MLX90614 Temperature sensor

The key feature of MLX90614 is that it is a contactless IR temperature sensor with high accuracy. So it can be used in industries to measure the temperature of moving objects like a rotating motor shaft. Due to its high accuracy and precision, it is also used in a wide range of commercial, health care, and household applications like room temperature monitoring, body temperature measurement, etc.

 

Working Principle of MLX90614

As mentioned earlier, the MLX90614 sensor can measure the temperature of an object without any physical contact with it. This is made possible with a law called Stefan-Boltzmann Law, which states that all objects and living beings emit IR Energy and the intensity of this emitted IR energy will be directly proportional to the temperature of that object or living being. So the MLX90614 sensor calculates the temperature of an object by measuring the amount of IR energy emitted from it.

 

How to use MLX90614 Thermometer Sensor

The MLX90614 Temperature sensor is manufactured by a company called Melexis. The sensor is factory calibrated and hence it acts like a plug and play sensor module for speeding up development processes.

 

The MLX90614 consists of two devices embedded as a single sensor, one device acts as a sensing unit and the other device acts as a processing unit. The sensing unit an Infrared Thermopile Detector called MLX81101 which senses the temperature and the processing unit is a Single Conditioning ASSP called MLX90302 which converts the signal from the sensor to digital value and communicates using I2C protocol. The MLX90302 has a low noise amplifier, 17-bit ADC and a powerful DSP which helps the sensor to have high accuracy and resolution.

 

The sensor requires no external components and can be directly interfaced with a microcontroller like Arduino. As you can see above the power pins (Vdd and Gnd) can be directly used to power the sensor, typically 5V can be used, but there are other versions of this sensor which can operate on 3.3V and 7V as well. The capacitor C1 is optional and is used to filter noise and provide optimum EMC. The signal pins (SCL and SDA) for used for I2C communication and can be connected directly to microcontroller operating on 5V logic.

 

The sensor is also sold as a module as you can see in the pinout image. But the sensor module is very similar to the sensor itself and does not have any additional components other than the sensor itself.

 

Applications of MLX90614

• Temperature Measurement of moving objects
• Industrial Thermal Gun
• Human Body Temperature Measurement
• Home/Office Temperature Control
• Livestock Monitoring
• Movement Detection

 

MLX90614 Dimensions

The MLX90614 is available in the standard TO-39 package making it easy to mount on a breadboard. Do note that this is a 4-pin TO39 package and hence the footprint will differ. The dimensions of MLX90614 is shown below.