Falling Icicles

Falling Icicles made their debut in my area 2009.  Initially they were hideously expensive and hard to find.  But secretly I always knew I would get some.

Then least year Big-W  / K Mart started sell small falling Icicles  sets ( 300mm long light bars) that that ran independently of each other.  closer inspection revealed some kind of controller at the top of the PCB. Unfortunately I didn’t have the time nor money to purchase a number of the ready made units.

Falling Icicles BaukoLites Style

I hacked together a design that will allow considerable flexibility.  The general concept is to create a small DMX based 16ch Controller that uses LED Constant Current drivers.  The Controller will be mounted at the top of the Icicles.   The LEDS will NOT be PCB mounted, but rather will be wired to suspend inside  1/2″ PVC tubing.

16Ch LED Falling Icicles

16ch DMX LED Icicle Controller

Let me stop here and say the biggest influence on my design was N1ist’s Color Sticks over as DIYC.com.  The two projects share a great number of common components.  Details of Mike’s project can be found here.

The Schematic for the controller available  here. <place marker only>

Making the LED strings

The final LED spacing has been on my mind for a while now.  I figure I need to address a number of areas:

  • LED viewing angle
  • LED Spacing (distance between LEDs in a single segment)
  • Segment spacing (distance between segments of LEDs)

25mm & 35mm Segment Spacing

The LED view area has a large affect on the the final product.  Most 3mm LEDs are very directional.  Sanding the LED surface may be a solution to diffuse the LEDs.  3mm Top hats may also be the best way to go.


THe blank PCBs arrived today.  Nice job.

Assembled Falling Icicle Controller









Software Considerations

I suddenly realised the Top LED segments MUST be channel 16.  this is no big issue but is makes chasing Lights easier if this is the case.  The SPI will clock out channel 16 first.

If I can I would like to build in some smarts in to the Controller.

The easiest options it to treat this like every other 16 channel controller and allocate 16 DMX channels.  This offers a would of flexibility.

However the more I think of how I want to use these icicles the more I reckon a simple single channel will be able to achieve everything I want.  So here is what I am thinking:

DMX Start 


Function DMX Start
0 9 All lights Off 100 109 All lights Off
10 19 Chase at 500mS rate 110 119 Chase 3 LEDs at 500mS rate
20 29 Chase at 450mS rate 120 129 Chase 3 LEDs at 450mS rate
30 39 Chase at 400mS rate 130 139 Chase 3 LEDs at 400mS rate
40 49 Chase at 350mS rate 140 149 Chase 3 LEDs at 350mS rate
50 59 Chase at 300mS rate 150 159 Chase 3 LEDs at 300mS rate
60 69 Chase at 250mS rate 160 169 Chase 3 LEDs at 250mS rate
70 79 Chase at 200mS rate 170 179 Chase 3 LEDs at 200mS rate
80 89 Chase at 150mS rate 180 189 Chase 3 LEDs at 1500mS rate
90 99 Chase at 100mS rate 190 199 Chase 3 LEDs at 100mS rate
200 209 All on dimmed at 5% 210 219 All on dimmed at 10%
220 229 All on dimmed at 15% 230 239 All on dimmed at 30%
240 249 All on dimmed at 50% 250 255 All on dimmed at 100%

the down side to such a method is remembering specific functions when programming vixen.

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