SMT172 connected to Raspberry Pi via I2C

Introduction

Regularly Smartec is asked for a temperature sensor with an I2C output. Because of the low power consumption of the SMT172 sensor itself, the self heating of the sensor is negligible, which contributes to its precision. An on chip integrated I2C interface would produce too much heat. The only way to preserve the sensors precision and still have an I2C interface, is to combine them on a tiny pcb. This board also does the calculations on the sampled duty-cycle and converts the result in ASCII data with an accuracy in the range of mK.

The board can be used in PWM mode (instead of I2C mode), to meet compatibility requirements with some existing (obsolete) SMT160-30 applications.

Highlights

  • Accurate measurement in full SMT172 temperature range
  • Measures the output of the SMT172 in 0.001 °C steps
  • Both I2C and PWM (SMT16030 like) output
  • Board temperature range 0 – 75 °C
  • Programmable secondary address, allowing for multiple sensors with interfaces on the same I2C bus
  • 3.3 V. regulator for powering the SMT172
  • Powered by the I2C bus itself
  • Can be used for all housings of the SMT172View or download SMT172TOIIC.pdf , click here.

Reference: click here.

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