If you want to build a contactless temperature measurement and looking for an idea, then this project is for you. Martin Nawrath has built non-contact infrared thermometer using MLX90614 and Arduino. This device can be used to measure temperature with range from -70 to +380 degree Celsius. Just connect the four leads to your Arduino and you will have an accurate thermometer with a resolution of 0.01 and accuracy of 0.5 degrees. The code below reads the object temperature which is emitted from the objects surface and the ambient temperature from the sensor itself.
The MLX90614 is an Infra Red thermometer for non contact temperature measurements. Both the IR sensitive thermopile detector chip and the signal conditioning ASIC are integrated in the same TO-39 can. Integrated into the MLX90614 are a low noise amplifier, 17-bit ADC and powerful DSP unit thus achieving high accuracy and resolution of the thermometer.
The thermometer comes with factory calibrated with a digital SMBus output giving full access to the measured temperature in the complete temperature range(s) with a resolution of 0.02°C. The user can configure the digital output to be PWM. As a standard, the 10-bit PWM is configured to continuously transmit the measured temperature in range of -20 to 120 °C, with an output resolution of 0.14 °C.