7400 competition entry: LED clock

Posted on Friday, October 21st, 2011 in 7400 contest by DP

Michael built an LED clock for the Open 7400 Logic Competition. He added 60 LEDs to an analog clock which are controlled by discrete logic chips.

This project uses a standard analog quartz clock and adds 60 LEDs clockwise around it to display the seconds.

There are 2 selectable modes via 2 jumpers:

Mode 1: Every second, each LED is activated one after another. After 1 minute, all LEDs are on. Then every second each LED is deactivated one after another. After 1 minute, all LEDs are off. This is continuosly repeated, so the seconds are visualized by LEDs. This mode uses an integrated 1 Hz timebase and loop-back mode of the shift registers. For this mode, jumpers JP1 and JP2 both need to be connected to positions 1-2 (see schematic).

Mode 2: All 60 LEDs can be controlled externally, for example by a microcontroller or by a PC. Thereby you have full control of the displayed LED patterns. In this mode, the signals /CLEAR, CLK and DATA of the 74164 chain have to be controlled externally via connector J1. For this mode, jumpers JP1 and JP2 both need to be connected to positions 2-3 (see schematic). .

Via the contact form.

Check out the video of it below.

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