Educational Notes Educational Notes



This list of notes enables you to understand Smartec products better and make it easier to get good and fast results.

All the information on these pages is free to copy and can be used for your own application.

If you have an application which is of interest for other users, please let us know and we will be pleased to extend the list with your application.

These engineering notes cover the five Smartec core products:

• Temperature sensor
• Humidity sensor
• Pressure sensor
• Universal interface
• Infared sensors

For information and suggestions:


Smartec BV
Delpratsingel 26
The Netherlands

tel: +3176 520 5353


Temperature sensor SMT172


In a limited temperature range the SMT172 scores better than a Pt100AA/1000AA at a much lower cost.
A comparison is made between the Pt100AA and our SMT172 on accuracy, calibration, hardware, etc.

How to build your I2C bus system on a Raspberry Pi  
Starters guide
READ more

Psychrometer based on wetbulb temperature measurement
READ more

Laser Solder Service for HEC and SOT223
READ more

SMT172 LabVIEW application for SMTAS08usb
application for accurate measurement of 8 Sensors based on LabVIEW
READ more 

SMT172 connected to Raspberry Pi via I2C 
a little software how to connect via Raspberry Pi multiple temperature sensors (I2C bus) 
READ more     

About sampling and measure over more periods
A theoretical article about accuracy when sampling duty cycle signals.
READ more          

Using analogue output for SMT172
Most simple measurement of the output of the SMT172 is by means of a low pass filter.
Apps for an easy and high accurate temperature controller and a temperature gradient detector.
READ more            

Arduino software for running SMT172 within 0.01 °C resolution and 0.1 °C accuracy
follow the link above

Scientific paper about the design of the SMT172
About the design, DEM and FoM (Figure of Merit)
READ more             

A two wire cable connection for the SMT172
by means of two diodes and a capacitor the SMT172 can be connected
via a two wire (shielded) cable to the microcontroller.
READ more                

SMTAS04USB mini and SMT08USBmini software for read and store temperature values.
dont forget to remover the 'pdf' in the filename
READ more    




Universal Transducer Interface (UTI)

A quick start guide about the use of the UTI
Based on the theory of the two port measurement and the
three signal technique a very accurate capacitance measurement (aF range) can be realized.
READ more (English)   
READ more (French)  

The three signal technique for UTI apps
Samples of the Pt1000 measurement and a capacitive sensor (2 pF range) the ease of use of the UTI is shown.
READ more    

A Micromachined Nanoindentation Force sensor
A capacitive force sensor has been designed and manufactured  and evaluated
for in situ nanoidentation experiments in a TEM.
READ more    

Measuring potentiometer and a Pt100/1000 with a UTI
READ more    

Measuring 8 Pt100/1000 elements with one UTI
READ more    

A measurement system for conductivity sensors
A low-cost accurate measurement system for four-electrode conductivity sensor is presented. Range 0.1 µS to 10 mS.
READ more    

A long cable application for Pt element measurement with UTI
Due to cable capacitances the accuracy of measurement in resistive applications will decrease.
Therefor is it advised to apply DC excitation for long cable application.
With this design cable length of over 150 meter can be measured with a very high accuracy
READ more    

Software for read and store capacitance and resistive output values of UTI evaluation kit
dont forget to remover the 'pdf' in the filename

READ more    

UTI evaluation board manual for software
READ more  

How to read output of the UTI
instruction set how to read and sample the output of the UTI. A simple method, usefull for any type of microcontroller
READ more

Accurate Pt digitizer.
To digitize PT100/1000 sensors Smartec has a single chip solution. This solution covers in one time the 2,3 and 4-wire interfacing. Using simple hard- and software it is easy to digitize for over the whole Pt  temperature range and with a high accuracy. In this application most of the hardware is replaced by software and following some simple rules it will be easy to measuring and calculating the Pt resistance accurately.


Connecting UTI to I2C toolkit to the Smartec Logging software.
Many users of the UTI will connect their UTI application to the Smartec logging software, especially when data has to be stored for later analysis in Excel. Therefore we have made a little software for an Arduino Nano to do this job.


Infrared sensors SMTIR9901 and SMTIR9902

Relation between black body temperature and the output voltage of the SMTIR9901/02 and SMTIR9902sil infrared sensors.
Measured at a sensortemperature of 25 °C and black body temperature range between 0  °C and 100 °C.
READ more  


Humidity sensor HS07/08A

Psychrometer based on wetbulb temperature measurement
READ more

Using saturated salt solutions it is possible to calibrate the HS07/08A humidity sensor in an accurate way.
By use of LiCl a three point calibration can be arranged.
READ more    

With a little analogue circuit and the HS07 humidity sensor, a DC output can be made for humidity controller.
READ more    


Pressure sensor SPD family

Introduction to Smartec Pressure Devices, SPD series pressure sensors.
READ more    

Quick selection guide for Smartec Pressure sensors
READ more  


With use of our SPD050SAhyb sensor it is easy to make a flow sensor based on an orifice in a tube.
Especially engineered for gasses like air (for ventilation systems)
READ more



Please send your application to us.