[Aaron] has been wanting to build his own binary desk clock for a while now. This was his first clock project, so he decided to keep it simple and have it simply display the time. No alarms, bells, or whistles.
The electronics are relatively simple. [Aaron] decided to use on of the ATMega328 chips he had lying around that already had the Arduino boot loader burned into them. He first built his own Arduino board on a breadboard and then re-built it on a piece of protoboard as a more permanent solution. The Arduino gets the time from a real-time clock (RTC) module and then displays it using an array of blue and green LED’s. The whole thing is powered using a spare 9V wall wort power supply.
[Aaron] chose to use the DS1307 RTC module to keep time. This will ensure that the time is kept accurately over along period of time. The RTC module has its own built-in battery, which means that if [Aaron's] clock should ever lose power the clock will still remember the time. The RTC battery can theoretically last for up to ten years.
[Aaron] got creative for his clock enclosure, upcycling an old hard drive. All of the hard drive guts were removed and replaced with his own electronics. The front cover had 13 holes drilled out for the LED’s. There are six green LED’s to display the hour, and seven blue LED’s for the minute. The LED’s were wired up as common cathode. Since the hard drive cover is conductive, [Aaron] covered both sides of his circuit board with electrical tape and hot glue to prevent any short circuits. The end result is an elegant binary clock that any geek would be proud of.