Hyperactive LED Xmas Tree

With elaborate light show and daisy-chain capability

Published in issue 12/2012 on page 36

While in the past we usually had to make do with a string of tiny, fragile light bulbs, which would flash at the most, now we can choose from many different types of LED lights with built-in light effects. But as a real electronics enthusiast you can, of course, make one that is much better and more elaborate, such as this Xmas tree which, with 56 LEDs can display an extensive light show lasting more than three-quarters of an hour.

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Products

Components

Controller board
Resistors
R1,R4,R14 = 4.7kOhm
R2,R3 = wire link
R5 = 330Ohm (optional)
R6–R13 = 680Ohm (820Ohm, 1kOhm, see text)
Capacitors
C1 = 47µF 16V
C2,C3 = 22pF ceramic
Semiconductors
D1 = LED, red, 3mm (optional)
IC1 = PIC18F2685-E/SP, programmed
Miscellaneous
X1 = 24MHz quartz crystal
K1 = DC adapter socket (e.g. Lumberg type 1613 20)
K2 = 2-pin SIL pinheader (optional)
K3 = 5-pin SIL pinheader
K4 = 16 pin-SIL pinheader (or short length of 16-way flat cable)
Optional: pushbutton for mode and reset
PCB # 120634-1 (see [1])

LED board
D1–D56 = high-ef ciency LED, 5mm
K1 = 16-pin SIL pinheader (see K4 controller board)
PCB # 120634-2