Temperature sensors
I linked this assignment to the final project where I will need to measure temperature with several sensors.
I investigated three types of temperature sensors and their connection to MCUs.
The following table summarizes the available technology. The selected sensors - NTC, LR35 and DS18B20 - are the one I found more common in the maker community.
The get accustomed using sensors I first tested them with an Arduino board. I then made a Satshakit board and repeated some of the tests, always using the Arduino IDE.
Testing with Arduino
The DS18B20
This integrated circuit sensor is very simple to use. Easy coonnection and temperature directly in degrees celsius
The LM35
This integrated circuit sensor is also very simple to use. It does not deliver a direct digital signal but a voltage and must therefore be properly connected with the board ADC device
The NTC
The thermistor delivers a variable resistance with temperature. Though vey cheap, its use is somewhat more complex since it must be connected to the board ADC device and to get the temperature some calculattions must be coded in the relevant sketch.
- Understanding the ADC device
- Using the sensor I selected for the project (availability, price, ranges of temperature, completness of datasheet)
VISHAY NTCLE100E3103JT2 TERMISTORE, NTC, 10KR
- Make the temperature vary
Testing with Satshakit
Since I decided two use a thermistor in my projected this is the only sensor I tested with the Satshakit I made.
Programming via FabIsp
Measuring temperature
Thermistor Temperature Calculation
The formula for calculating temperature from the thermisotr resistance values is provifìded on the component datasheet:
I have also created a spredsheet to calculate ADC values and temperature as a function of resistance Follow the link
The assignment ends with the production of a specific board which, being part of the final project assignment, is detailed in the relevant sections: PCBs design and production
