ATtiny84 Powered Minimalist LED Clock

LED Clock ATtiny84

We feature a lot of clock builds on HaD, and the reason is that they are cool. Even simple ones are cool. Not everyone can say they built a clock. [Chris] took a ride on the DIY Clock train and came up with this LED-based clock that is controlled by an ATtiny84 chip.

The clock has 24 LEDs total, 1 for each hour and 1 for every 5 minute increment. The 24 LEDs are arranged in 2 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. The main image above shows 6:40.

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. [Chris] decided to use some 74HC595 shift registers to increase the IO pins on the ATtiny. The entire build is installed on a protoboard with quite a bit of point-to-point wiring. A simple tinted plastic case finishes the project and gives it a modern look.

[Chris] made the code for his clock available in case any readers are interested in making one.

LED Clock ATtiny84

LED Clock Looks Cool AND Tells Time

LED Arduino Clock

Clocks have taken many forms of the years, starting with shadow clocks and sundials in Egypt around 3500 BC. Obviously, these could only tell the time while the sun was out. Water Clocks followed which could track time in the dark. Water Clocks are basically a bowl with a hole in the bottom. This bowl was set in a container filled with water. The water entered the bowl at a consistent rate and graduations on the inside of the bowl showed how much time had passed.

Mechanical clocks followed, as did quartz and the atomic clock. We have now entered a new era in time-telling, the Bamboo LED Clock. [Pascal] brings us this funky fresh chronometer all the way from Germany.

The front face is made from a bamboo pizza plate and gives the clock some modern minimalist pizzazz. A 1-meter long LED strip is attached to the circumference of the plate and contains 60 individually assignable RGB LED’s. An Arduino and Real Time Clock are responsible for the time keeping and coordination of the LED’s.

As you can see in the photo, 2 of the LED’s colors are used. The single red LED indicates the hour. The strip of blue LED’s show the minutes. If you’d like to build one of these [Pascal] has shared the Arduino code on his Instructables page.

A Clock Built from Scraps


Who doesn’t love a good surplus store? [Tyler Bletsch] just finished up this awesome clock hack by re-purposing a scrapped medical circuit board.

Ax-Man Surplus in Minneapolis has all kinds of goodies and it’s been around a long time (here’s a hack from the ’90s that source from the store). One day while digging through their inventory, [Tyler] found a bunch of scrap circuit boards with 7-segment displays. At $2 a pop, he decided to risk it to tinker with.

He quickly identified the main chip on the board to be a common LED driver (MAX7221) and began reverse engineering the board by tracing the circuit. He actually has a brilliant guide on his website about how to make circuit tracing way easier. From there it was just a matter of loading a MAX7221 library onto a ATtiny44, adding a 16MHz crystal, and since there’s an extra 2 digits available on the display… a temperature sensor too!

It’s a great little hack, and as it turned out, there wasn’t anything wrong with the boards, except for a minor typo in the company’s name. Hooray for reusing scrapped parts!