The MLX90614 infrared temperature sensor is contactless infrared sensor. You only need a line of sight with the object you are targeting. It is an infrared thermometer designed for non-contact temperature sensing. 

Due to its built in low noise amplifier, 17-bit ADC and powerful DSP unit, a high accuracy and resolution of the thermometer is achieved. This well-known sensor with its 0.5℃ accuracy level has many applications in healthcare and industrial control.

 Featrures

• Operating voltage: 3.3 ~ 5V
• object temperature: -70 to +380°C
• High accuracy of 0.5°C over wide temperature range
• I2C interface
• Power saving mode
• Automotive grade

 MLX90614 infrared thermometer Datasheet.

Sparkfun tutorial and hookup guide for MLX90614 infrared thermometer sensor.

Arduino code and library for MLX90614 infrared thermometer sensor.