Motivation
I wanted an electronic clock with an alarm so I can view the time when I go to sleep and wakeup. I wasn’t happy with the retail solutions so I ordered this kit and assembled it. I’ve got to say, it’s superior than an off-the-shelf solution.
Here is the product page
Product Description
The pinout for the 4-digit 7-segment display is unique. Usually it’s DIG1, DIG2, DIG3, DIG4, a, b, c, d, e, f, g.
For accurate time-keeping during a power cycles, the widely-used DS1302 RTC module is used. It is powered by a separate coin cell.
A buzzer allows an obnoxious chime to wake you up.
A light-dependent resistor (LDR)/photoresistor configured as a voltage divider allows the ambient temperature to be measured and displayed.
The UI is surprisingly intuitive even though it’s two buttons. The two buttons are used to configure the time, date, brightness and alarm time.
Main power supply is via a dc jack. Although, there is no protection if the user inserts 9V or 12V since these are common voltages available via a barrel jack connection. The silkscreen says 5V but additional protection would make it more robust.
A cool feature is that when the display alternates the colors on the individual segments change.
