2. Construction

The following diagram, taken from page 6 of the MLX90614ESF datasheet (749k pdf), shows the MLX90614ESF pinout as seen when looking at the top of the sensor.

• VSS: Ground. The metal can is also connected to this pin.
• SCL / Vz: Serial clock input for 2 wire communications protocol. 5.7V zener is available at this pin for connection of external bipolar transistor to MLX90614A to supply the device from external 8 -16V source.
• SDA / PWM: Digital input / output. In PWM mode, the measured object temperature is available at this pin Pulse Width Modulated. In SMBus-compatible mode, this pin is automatically configured as open drain NMOS. The sensor ships in SMBus-compatible mode.
• VDD: External supply voltage (4.5 – 5.5 V).

Connect the sensor to the Orangutan as shown below to enable SMBus communication. If you are using an Orangutan based on the ATmega328, ATmega168, or ATmega48, connect its PC4 pin to SDA (sensor pin 2) and PC5 pin to SCL (sensor pin 1); if you are using the Orangutan X2, which is based on the ATmega644, connect its PC1 pin to SDA and PC0 pin to SCL. VSS (sensor pin 4) connects to the Orangutan’s ground rail, and VDD (sensor pin 3) connects to the Orangutan’s regulated 5V power bus. It is recommended that you solder a 0.1 uF capacitor between power (VDD) and ground (VSS).

MLX90614 connection to SMBus.

MLX90614 temperature sensor connected to an Orangutan SV-168.