Vermes
Advanced Member level 4
It is a second version of the mini thermometer. Originally it was made on a piece of universal board and has a display. This project is smaller and has more advanced features. New version displays HELLO (hide the initiation of the thermometer) and ERROR when there is no sensor. Reading with the frequency of 1Hz. To avoid waving 0,1 degree Celsius, it was set that the change shows only when the delta is 0,2 degree Celsius. Due to that, the accuracy 0,1 degree Celsius is lost, but it is not so important. It works like that: when the temperature changes from 12,3 to 12,2 degrees Celsius, 12,3 degrees is still displayed. When the temperature changes to 12,1 – 12,2 is displayed. If it changes to 12,4 – it shows 12,3. The inertia is artifically increased.
Pictures of the original and final version:
The device displays the temperature in the interrupt. Displaying is off when reading – it is set like that so there is no blinking. The main loop is delay and read.
Hardware:
- Atmega8L TQFP
- thermometer DS18B20
- programming/thermometer socket (between display/driver boards)
The entire device fits behind the display. The board was made by thermal transfer method, protected by transparent varnish.
Link to original thread (useful attachment) – Mini termometr na AVR