The device is made on the controller 51 of the family with internal flash memory, for measuring the temperature is used, widely known, cheap (relatively), an affordable DS18B20 sensor, to count the time it was decided to use a chip (called "primary clock") - DS1307.

Temperature sensor. The DS18B20 sensor is very widely known, it is used in almost every second temperature meter diagram. Detailed information about it is easy to find on the Internet pages. Here, only I will note the most important thing - the sensor sends data (or data exchange) via the MicroLAN interface, or otherwise called, 1-Wire. In my opinion, not the most convenient interface, from the point of view that it is difficult to implement it on C (problems with a call to completely concrete time delays), the rest of the interface is worthy of attention and modern.

Watch of real time. The DS1307 chip inside itself has a lot of things: a quartz generator, a bunch of meters (from seconds to year), 56 memory bytes, a power tracking scheme, an I2C interface controller. There are many opportunities for this chip, but I use only their insignificant part - I do not use the inner calendar, internally RAM, although it is possible. The most important thing is that it is very easy to work with this microcircuit. I2C interface after my study I really liked - a simple, reliable, understandable, easily implemented. But the most important thing in this chip is that when dumping the nutrition, time is not reset!

The device works like this: the timer is constantly working in the microcontroller, which has already previously explained by the method generates interruptions once per second, they are in turn countable, and when their number becomes equal to 8, indications shown on the scoreboard and temperature measurement. This function of the interrupt processing program is exhausted. In the main cycle of the program, an indication is constantly carried out (it is dynamic) and the keyboard survey. The device is powered by

DC source with voltage 8-12V.