gres
Full Member level 4
Prototyp was made on piece of paperboard, that leads to real forest of wires. But this way allow to easy and fast add some changes into construction.
There is no any additional functions like stopper or alarm. Clock should just showing time and looks nice on the table. As a extra function you can find battery back up in case of electricity damage. Besides it make “bip” sound at every hour. All casing Is made of transparent Perspex, after sunset it display on blue. But the best trick is smoothly brightness change depends on room bright. Thanks to that, at day numbers are clear, and at night they don’t jar.
All integrated circuits are from CMOS series. Generator with frequency 1/60 Hz makes 4060 system stabilize by quartz resonator with 4520 and one logic gate. Most important job – counting minutes and hours is made on 4026 counters, and logic gates take care of right reset. To set the time we use two buttons. Three potentiometers are responsible for display brightness, point of turning on dimmer and it brightness. All is powered by power supply with DC 12-18V. current take is from 30 to 180mA depends of lights.
Clock can work on batteries thought 70 hours. In this case hour is very light display so you can still check the time, casing dimmer, “:” mark and every hour “bip” is off.
Automatic brightness works on negative current stabilizer LM337. Stabilizer is necessary to avoid depending brightness and number of flashing segments.
More information at : https://www.elektroda.pl/rtvforum/topic1539473.html