LED clock 
The LED clock consists of 60 LEDs which are placed circular around a common analog clock. The LEDs are used to display the seconds. Essential part of this circuit is the LED driver MAX7219 from Maxim. A datasheet is available on Maxim's homepage. The clock is controlled by the microcontroller AT89C2051 from Atmel. This microcontroller is clocked at a frequency of 12 MHz from which results a time base of 1 microsecond. Via software dividers one clock impulse per second is generated which is used for updating the LED display. Two different display modes can be adjusted by a jumper:
1. The LEDs are switched on one by one every second until all LEDs are on after one minute. After that they are switched off one by one every second. This sequence is repeated.
2. The LEDs are switched on one by one every second until all LEDs are on after one minute. After that it starts from the beginning by switching on the first LED.
1. The LEDs are switched on one by one every second until all LEDs are on after one minute. After that they are switched off one by one every second. This sequence is repeated.
2. The LEDs are switched on one by one every second until all LEDs are on after one minute. After that it starts from the beginning by switching on the first LED.
The schematic and the software can be downloaded here:
Project files for hardware and software in ZIP format:LED clock V1.0
For the hardware the freeware version of Eagle 3.55 is required. It is available for free from CadSoft.
Schematic in GIF format:Schematic of LED clock
Programmed microcontroller:If you are interested in a programmed microcontroller, please send an email including the project name
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