Home made car clock and thermometer

[Vermes]

This simple clock and thermometer can be easily mounted in any car. Program was written in C. There are two versions of the thermometer:

1. welcome description (like „Hello, have a good trip”) is displayed and then temperature from two sensors DS18B20 is refreshed every 5 seconds
2. welcome description, then after 10 seconds time with date and day of week is displayed and replaced with temperature every 5 seconds. DS1307N, which operates from -40 degrees Celsius is used for measure time. Two sensors DS18B20 are used for temperature measurement. Time and temperature are displayed in change, because used LCD displayed has only two rows

Thermometer is operated using three buttons. In the first version, you do not have to use the buttons at all.

Functions available in the first version:

• swapping places of displayed temperatures on the display (if temperature sensors were inversely mounted by mistake, internal temperature will be dispalyed as external, using that function you can exchange the temperature dispalyed)
• displaying the welcome description (if it is displayed or not). Additionally, you can turn the description off any moment
• displaying information on glazed frost
• display brightness adjustment (15 grades of regulation)
• additional function (without entering the menu) – quick turning on and off the display

Menu in the second version with clock is similar – with functions that are used for time setting.

The clock is battery maintained, what means that thermometer does not need to be powered all the time.

HEX files for each thermometer and PCB can be found at the original thread of this project.

Pictures of the first version:



And the second version with clock:



When thermometer is without clock (in the first version), temperature is refreshed every 5 seconds, resolution is 0,1 degree Celsius. If temperature outside is between -2 and +2 degrees Celsius, message about glazed frost is displayed together with 3 times smooth brightening and dimming of the display.

Link to original thread (useful attachment) – Zegarek i Termometr do samochodu