A Maker named Aaron has built a rather impressive binary clock using the shell of an old, discarded hard drive. The unit is powered by a DS1307 Real Time Clock (RTC) module paired with an Atmel ATmega328 microcontroller (MCU).
”As I have an abundant supply of old hard drives, I went the upcycling route and used one for the enclosure. Should add to the clocks nerd cred as well, which can’t hurt,” Aaron explained in a recent blog post.
“You typically need a torx screwdriver bit to crack open most hard drive cases. However, you can bust out some dodgyness and use a flat head if need be.The only parts to be re-used were the body and cover of the hard drive, [although] there’s also some handy rare-earth magnets that can be salvaged.”
Aaron kicked off the binary clock project by marking a grid, then punching and drilling the holes, which he describes as a common LED arrangement for DIY binary clocks. Simply put, the left two columns represent the hours, while the right side displays the minutes.
“Each LED is installed and secured into place with a bit of hot glue. All the LEDs negative legs are soldered together creating a common ground connection. A color coded wire was soldered to each positive connection then insulated with another healthy dob of hot glue,” he continued.
“I had a couple of ATmega328 microcontrollers with Arduino bootloaders (can be programmed by an Arduino) so I breadboarded out a functional Arduino (hackduino) and tested it with the standard blink sketch.”
Aaron then adopted a more permanent model using a protoboard with the RTC – adding outputs for each LED with a resistor in series, 7805 5V regulator and other supporting passive components.
”Once everything was connected up, I let it run naked for a couple of days to make sure everything was sweet. A spare 9v wall wort provides enough power for the unit,” he added.
According to Aaron, the RTC “remembers” the time for approximately 10 years on its own battery, although it is capable of drawing power from an external source when available.
Last, but certainly not least, the Arduino sketch uses Adafruit’s RTC library to interact with the RTC module and ask for the current time/ The sketch then takes those values and calculates which LEDs should be lit to display the current time in binary format.
Interested in learning more? You can download the code here and check out the project’s official page here.
Atmel | Bits & Pieces 