A Maker by the name of Chris Gunawardena recently created a DIY minimalist LED clock powered by Atmel’s ATtiny84 microcontroller (MCU).
As HackADay’s Rich Bremer reports, the clock is equipped with a total of 24 LEDs, with one group designated for each hour, while the other displays five minute increments.
“The 24 LEDs are arranged in two concentric rings. To display the hour, both LEDs at the same angle are lit up. To show the minutes, just the inner LED is lit,” writes Bremer.
“If you are familiar with the ATtiny84 you know that it only has 12 in/out pins, which is significantly less than the amount of LEDs that need controlling.”
As such, Chris ended up using a number of 74HC595 shift registers to increase the IO pins on the ATtiny.
Essentially, the entire build is packed onto a protoboard with point-to-point wiring, which is housed in a basic tinted plastic case.
Interested in learning more? You can check out the project’s official page here.