Intro: LED Digital Clock
This instructable is to make a DIY LED clock.
Step 1: Designing the Shape
The first thing that I did was make a CAD drawing in Autodesk. The drawing shows the sets of wholes that need to be drilled. For my LED array I made a grid of 8x5 in which each bit was 5 LEDs.
Step 2: Making the Actual LED Board
The next thing to do was setting up the drill press and drilling all of the holes. I drilled a little bigger than 5mm just to accommodate them a little bit better. I drilled smaller pilot holes and then the final 5mm to make sure that the Plexi-glass didn’t crack. After drilling 400 holes, I then spray painted it flat black. This was the last step to make the mounting frame for the LEDs.
Step 3: Wiring
The next step was placing all of the LEDs into the plastic jig. When placing the LEDs, make sure that the polarity of the terminals is all in the same direction. The shorter length is the negative terminal while the longer length is the positive terminal. The next step is to solder the like terminals together. From this I need to solder it in a way of multiplexing. Multiplexing allows me to drive the 40 individual LED blocks with only 13 pin outputs. So, I soldered all of the positive cathodes of the LEDs in vertical patterns. I then soldered all of the negative cathodes of the LEDs in a horizontal pattern. This allows each LED to be controlled at once. It however does not work well with multiple output signals since it could trigger multiple LEDs to light up. To read multiple outputs, there needs to be a refresh rate to allow this to happen.
Step 4: Clock Software
The software allows for the time to be displayed. (0)(00):(00)(00) is the format for the time. The am and pm is not displayed on this clock, but you could change the position of the colons to signify this.