The MintyTime binary clock kit. This kit is a perfect “make” project which includes both electronics and a physical build.
=> Buy one from WickedDevice.com now for $23.

Features include:
– Seconds ‘heartbeat’ LED, 6 hours LEDs and 7 minutes LEDs.
– Light sensitive dimming.
– Long battery life. See how we optimized power usage.
– Easy to adjust with 2 buttons.
– Fits into an Altoids tin.
– Detailed assembly instructions and theory explaining how it works.

MintyTime is a self contained, ready to make kit. It uses the 74HC595 shift register and ATtiny2313 chip (both included in the kit).

Note: This kit includes everything *except* the Altoids tin and AAA batteries. Build time is between 3 and 4 hours. Although all steps is are “beginner” level, it includes both electronics and making the physical unit, and therefore is an intermediate level project.

UPDATE: You can also mount it on a sheet of plexiglass instead of an Altoids tin.

So … how do you tell the time?
Each hours and minutes row is a multiple of 2, starting at 1, then 2, 4, 8. The green LED is pulses the seconds, one second on, one second off.
The four columns are, left to right:
– Hours 10’s (2 LEDs)
– Hours units (4 LEDs)
– Minutes 10’s (3 LEDs)
– Minutes units (4 LEDs)
Simply do the addition, and you have the time in 24-hour (military time) format.

Next …. Make it!