Quelltext der Seite WSAL13461 – Infrared Temperature Sensor/en

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'''Documentation notice:''' This technical documentation was independently rewritten from an archived supplier source. Check technical details and commands against the product version and manufacturer documentation before use.

== Summary ==
Contactless infrared temperature sensor based on the MLX90614 chip with SMBus/I2C interface, 35° field of view and object measurement range up to 380 °C.

== Related products at JW Tech ==
* [https://shop.jw-tech.eu/p/WSAL13461 WSAL13461 – Contact-less Infrared Temperature Sensor]

== Technical overview ==
* Chip used: MLX90614ESF-BCC; the module offers both a digital PWM output and SMBus output, with the documentation focusing on SMBus.
* Supply voltage: 3.3 V to 5 V; built-in level translation allows direct connection to 3.3 V or 5 V MCU systems.
* Measurement ranges: area −40 °C to 85 °C; object −70 °C to 380 °C; resolution 0.02 °C; accuracy ±0.5 °C for 0–50 °C.
* Field of view (FOV): 35°, defined by the 50% radiation signal received by the thermopile; most accurate when the object covers the full FOV.
* Dimensions: 28 mm × 16 mm; mounting hole diameter 2.0 mm.
* SMBus is a two-wire interface based on the I2C principle; start and stop signals are defined via SDA transitions while SCL is high; every received 8-bit data block is acknowledged with ACK/NACK.
* Default I2C address for a single sensor: 7-bit address 0x00; read operation sends (SA&lt;&lt;1)+0 = 0x00; write operation sends (SA&lt;&lt;1)+1 = 0x01.
* Accessing RAM registers: command 0x00 OR register address; ambient temperature at 0x06, object temperature at 0x07; EEPROM access uses command bit 0x20.
* Raw data to Celsius conversion: ((TempData_H &lt;&lt; 8) + TempData_L) × 0.02 − 273.15.
* When multiple sensors share the bus, the slave address can be changed via EEPROM to avoid address conflicts.

'''Commands and examples – verify before use:''' 
<syntaxhighlight lang="text">
sudo raspi-config
sudo reboot
sudo apt-get install wiringpi
wget https://files.waveshare.com/wiki/common/wiringpi-latest.deb
sudo dpkg -i wiringpi-latest.deb
gpio -v
sudo wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.71.tar.gz
sudo tar zxvf bcm2835-1.71.tar.gz
cd bcm2835-1.71/
sudo ./configure && sudo make && sudo make check && sudo make install
sudo apt-get update
sudo apt-get install python3-pip
sudo apt-get install python3-pil
sudo apt-get install python3-numpy
sudo pip3 install RPi.GPIO
sudo pip3 install spidev
sudo apt-get install p7zip-full -y
sudo wget https://files.waveshare.com/upload/5/53/Infrared-Temperature-Sensor-Code.7z
7z x Infrared-Temperature-Sensor-Code.7z
cd Infrared-Temperature-Sensor-Code/RaspberryPi/
</syntaxhighlight>

== Notes and version constraints ==
* The stated default I2C address 0x00 applies only to a single sensor; with multiple sensors, the address must be changed via EEPROM, which requires additional steps.
* The conversion formula assumes raw data are correctly read; error conditions such as EEBUSY or EE_DEAD can affect the measurement.
* The exact measurement distance depends on the FOV: for a 5 cm radius object, the maximum distance for accurate readings is about 7 cm; greater distances cause deviations.
* Installing BCM2835 and wiringPi may fail depending on OS version; on Bookworm only lgpio is available.
* The example files must be downloaded and unzipped; without proper setup the examples cannot run.

== Source and revision record ==
* [https://www.waveshare.com/wiki/Infrared_Temperature_Sensor Infrared Temperature Sensor - Waveshare Wiki]
* Source revision: 69047
* Captured: 2026-08-30T03:48:16+00:00
* SHA-256: <code>0f81fdfd9df8625d325d3c732540ecd30e7cbacad41c025cd93c0825a3ca4c33</code>