Charlieplexed clock gallery 7

Seven segment 2mm orange domed LED clock

A seven segment clock with a difference. Every LED is individually addressable, which means more interesting shapes can be made and scrolling marquee effects too. The digit height is 2" tall. There are 39 LEDs in total,driven from a 14 pin 16F688 PIC.

As only one LED is ever on at once, it relies on persistence of vision to appear as if the LEDs are all lit at once.

To create a display that did not flicker I found that I had to run my main program loop at 2048 times a second. This means that each LED is updated 52.5 times a second. Doing this while computing the time and adding a scrolling effect was just about as much as the PIC running on its internal 4 meg oscillator could manage.

I can run the PIC using an external 20meg crystal, but I don't have enough pins to use two for this purpose, so I shall have to use a bigger PIC.

Due to the fast refresh rate, I found it impossible with my camera to take a non-flickering movie of this clock in action, which is a pity as it is beautiful.

I have lots of ideas for animations on this clock, so I shall certainly be revisiting this one.

This clock is not for sale, but I intend to produce a similar revised clock very soon.

With an orange filter the display looks even better.