Clocks made from blinking LEDs always make for fun projects. [Earthshine] built a clock that displays time abstractly using an 8×8 RGB LED matrix. The video embedded after the break illustrates how to read the time but here’s the gist of it: One LED is illuminated in the outside box of LEDs and moved in a clockwise motion to approximate seconds. Inside of this, there are four quadrants; upper left indicates hour-tens digit, upper right hour-ones, lower left minute-tens, and lower right minute-ones. This certainly makes for an interesting conversation piece!

There is no schematic and no code available but it’s really the concept that we’re interested in. If you must know, [Earthshine] bases this build around an Arduino. A DS1307 real time clock keeps the time, while four 74HC595 shift registers are utilized to control the three LED colors and the multiplexing.

Read the rest of this entry »

[Spikenzie] has created an 8×8 LED array that fits inside an ikea frame. He multiplexed the 64 red LEDs on a PCB with connections on the back. He then used a MAX7129, an LED multiplexer and driver, driven by a PIC over SPI to do animations and play pong. He then encased the array in laser-cut cardboard and white acrylic to get large dots. This entire assembly was then placed inside an Ikea RIBBA picture frame. The result is an aesthetic homebrew display that is easy to control.

Related: 64pixels are enough

[punkky] has been documenting his adventures building digital clocks. They each use six 7-segment LED displays, but he’s been gradually changing how they are built. The first version used a CMOS BCD-to-7-sement latch on each display, which is tied to a PIC16F627a. For the next run, he added multiplexing, so he could drive all the segments using just thirteen pins. He’s posted a final schematic with code and details of how the clock timing actually works.

Blinkomat, an LED matrix, turned out quite well. 240 LEDs controlled by an Atmega 16 is what we call a decent bookshelf decoration. The dimensions of 12×20 were chosen due to the fact that the microcontroller has 32 I/O lines.  The LEDs are switched on and off using multiplexing. The brightness, controlled by pulse width modulation can be varied by 16 levels.  The overall effect is quite smooth an fun to look at.  He has programmed it to do other things than just cellular automata.  Our personal favorite is a simple sine wave. Watch it after the break.

Read the rest of this entry »