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Digital Temperature sensor SMT172

The Smartec SMT172 is an ultra-low power, fully calibrated, high accuracy digital sensor developed at the Delft University of Technology (TUD). Using the most recent advances in silicon temperature sensing technology, the SMT172 has applied sophisticated IC design techniques and high-precision calibration methods, to achieve an overall accuracy of 0.1ºC in the range of -20ºC to 100ºC (-4ºF to 212ºF) and an accuracy of 0.4ºC from -45ºC to -20ºC and 100ºC to 135ºC with a resolution of 0.0001ºC. The SMT172 requires only one digital input. SMT172 is an efficient alternative for Pt100/1000AA applications in a limited temperature range. The high accuracy of the SMT172 in the temperature range of -45 to +50 ⁰C makes it an easy and low cost solution compared to a classical solutions. Save development and production cost with the SMT172 temperature sensor and a little bit of software. Applications include medical, industrial and environmental projects.



  • Overall accuracy 0.1ºC in the temperature range of -20ºC to 80ºC. (TO18).
  • Overall accuracy 0.25ºC in the temperature range of -10ºC to 100ºC.
  • Full temperature range from -45ºC to -135ºC (-49ºF to 275ºF).
  • PWM signal is proportional to the temperature.
  • Supply voltage 3V, 3.3V, 5V (Voltage range from +2.7V to +5.5V).
  • 7 packages ( TO18, TO92, TO220, SOIC-8L, SOT223, HEC).
  • SMTRVS1802 sensor in a robust stainless steel probe with cable.
  • SMTRVSHEC1 sensor in a robust stainless steel probe with fine point and cable.
  • SMTAS04 application board with USB for up to 4 x SMT172 sensors.
  • SMTAS08 application board with USB for up to 8 x SMT172 sensors.
  • SMT172toI2C interface board with I2C and PWM (SMT160-30 like) output.

Infrared temperature sensors and modules with I²C

The Smartec SMTIR infrared sensors are sophisticated full silicon infrared sensors and thermopiles. The sensors can measure the radiation temperature without making contact. Thermopiles are structures composed of thermocouple junctions that convert thermal energy into electrical energy (The Seebeck effect).  For different radiation temperature ranges, various filters are available. Sensor SMTIR9902 and the new SMTIR2102 also contain an NTC temperature sensor for measuring the temperature of the sensor itself. The temperature range of the sensor-element is between -40 to 100 °C. The sensor is available in a standard TO-5 encapsulation and comes equipped with a 5.5 micrometer filter. For a of 7° small field of view, there is an infrared sensor available with a silicon lens. The output voltage of the infrared sensor required amplification before presenting to the AD converter. 

Calibrated modules SMTIRMOD with infra-red sensor, amplifier and I²C interface speed up infrared temperature sensing. For USB input use the SMT AS02I2C I²C to USB converter.

Partnumber View Temperature Interface Voltage
SMTIRMOD09sil 14° <300°C I²C Module 4 to 16V
SMTIRMOD09std 70° <50°C I²C Module 4 to 16V
SMTIRMOD09micro 120° <50°C I²C Module 3.3V
SMTIR9901   -20..+100° Analog TO-05  
SMTIR9902   -20..+100° Analog TO-05  
SMTIR9902sil 7.2° -20..+100° Analog TO-05  
SMTIR1202 New 88° -20..+100° Analog TO-05  

Link to Infrared sensor products and datasheet




Arduino and Raspberry PI connect to SMT172

Measure temperature with an Arduino or Raspberry Pi with the Smartec SMT172 digital sensor. 

Link to SMT172 with Arduino

Link to SMT172 with Raspberry PI


Universal Transducer Interface SMT UTI

The Smartec Universal Transducer Interface (UTI) is a sensor-to-time signal converter, based on a self-calibrating period-modulated oscillator. Sensing elements can be directly connected to the UTI without the need for extra electronics. The output is digital and can communicate with any type of micro-controller. High accuracy and resolution (13 to 14 bits).  The UTI can operate in 16 different modes. To obtain accurate results in any of these modes, only a reference element of the same kind as the sensor is required. The UTI provides interfacing for all kind of resistive and capacitive sensors.

For convenient design-in, there is an evaluation board available. The UTI evaluation board and free down-loadable software ensure that custom applications will be up and running in no time.  


  • Full sensor solution on a chip.
  • 16 different measuring modes.
  • Capacitive sensing 0-2pF, 0-12pF, variable to 300pF.
  • Typical 4 wire (PT100) measurement.
  • Resistance bridge measurement.
  • Measure 8 capacitors with one UTI by using the MUXC01 multiplexer.
  • Long distance 3 and 4 wire measurement 
  • Very stable measurement system.
  • Supply voltage 2.9V to +5.5V.
  • SMT UTI Toolkit application board with USB interface.
  • SMT UTI Toolkit with I2C interface.

Link to SMTUTI transducers, application boards and datasheet.

Link to SMTUTI Quickstart


Humidity sensors SMTHS07 SMTHS08

The Smartec humidity sensor is a two terminal capacitor, which increases in value as water molecules are absorbed into its active polymer dielectric. The capacitor consists out of a base plate and a water permeable platinum top plate. Measuring humidity is rather complex. Humidity in the air is measured as the fraction of the maximum amount of water that can be absorbed at a certain temperature. In air, at a given temperature, this fraction can vary between 0 (absolute dry) and 100 % (the point where condensation begins to form). Many classical sensing techniques, such as mechanical devices or resistive sensors, are temperature dependent and the wet bulb thermometer is also pressure dependent. With the Smartec humidity sensor, Relative Humidity (RH) can be measured without the complicating factors of temperature and pressure compensation.  

Link to SMTHS07 SMTHS08 products and datasheets


Pressure sensors SMTSPD

The Smartec pressure sensors, SPD serie are silicon based level sensors that are available in different housings. These pressure sensors are typically mounted on a printed circuit board (PCB). Pressure range from 10 mBar and to 20 Bar gauge, absolute and differential. In case of the absolute version, a reference vacuum chamber is formed on the die during manufacturing. The principle of the Smartec Pressure sensors is that pressure in a liquid or gas bends the sensor membrane. The membrane has a very thin conductive screened layer that bends with the membrane and changes the resistance. The resistance is measured by a Wheatstone bridge. The sensors are available with an internal amplifier with temperature compensation to provide a stable analogue output.  Smartec pressure sensors have a wide range of outputs including bridge, analogue, digital and I2C output. If a sensor is required that is not available in our standard parts then please talk to us and if possible we will provide a custom versions that meets your requirements. 



  • Gauge, Absolute, Differential sensors.
  • Bridge, Analogue and Digital output.
  • mV, amplified analog, or digital outputs
  • Temperature compensated or Uncompensated
  • Through-hole or surface mount (SMD)
  • Packages ( TO05, SILA, SILR, DIL, Hyb, SOIC-6, SMD8, UBS).
  • Can't see the required pressure or package, contact us with your specification. (MOQ applies.)



Contact Us

MMS Electronics Ltd
Unit 3, Whiteley Court
Pool Road, Pool in Wharfedale
Leeds LS21 1FR
United Kingdom


Tel: + 44 (0)1943 877668