Height: 20cm Width: 50cm Depth: 12cm
This clock shows the time and temperature in 3 seconds interval.
The clock is totaly made up from discrete components (gates and counters).
What makes the clock tick is the mains frequency. The 50Hz mains
frequency is divide so that a one minute pulse is generated. This pulse feeds
a counter which counts until 1439 (23:59) and will then be reset.
The output of the counter is translated by an EPROM to drive the 7 segments displays.
The display itself is made up by individual LEDs (9 per segment).
The display has a controlable ilumination using a simple LDR in the circuit that drives the powerline to the displays.
This is done to ensure that the display can be read in normal daylight but will not be to bright at night.
The temperature is measured by an ADconverter and its output
is send to the translater EPROMs.