FAST Finally Affordable Snowfall Tube
F.A.S.T (Finally Affordable Snowfall Tubes)
- NOTE - THIS PAGE IS A WORK IN-PROGRESS - IT IS NOT COMPLETE YET *
What is FAST
FAST was created by Cory Helmuth as a inexpensive substitute for commercial snowfall (meteor) tubes. It consists of a FAST Controller PCB that drives 1-8 LED Segment PCBs each with 7 LED's per segment for a total of 7-56 SuperFlux LED's. Based on the numbr of LED Segment Boards used, the snowfall tubes can be between 6" to 48" in length.
The FAST is designed using a concept called Charlieplexing Charlieplexing, in its simplest form, works using a matrix of complementary pairs of LEDs. This allows a large number of LEDs to be driven by a small number of I/O pins from a PIC microcontroller. In the FAST, 56 LEDs are controlled using just 8 connections!
FAST Controller
The FAST Controller is a brains of the FAST, it contains a PIC16F688-I/P Microcontroller. The PIC must be programmed with the FAST software. The FAST controller is connected to a clean and stable 5VDC input to power the microprocessor and the LEDs. The FAST controller output is connected to a FAST LED Segment PCB.
FAST LED Segment
The FAST LED Segment board is an approximately 6" long modular board that contains 7 Piranha Style Superflux LEDs connected in a Charlieplexed fashion. The boards are designed to allow multiple boards to be daisy chained to allow various length tubes to be constructed. From 1 - 8 boards can be connected to each FAST controller creating a 6" to 48" long snowfall tube.
Using the FAST
The FAST is run on 5vdc. The operation of the FAST is quite simple. You apply power and the tube starts to run. When you want it to stop you remove power. If you want it to make a half fall. You simply remove power before it get's to the bottom of the tube. If you want it to fall twice you leave power applied long enough to get two falls. Length of time with depend on fall time that you set before you programmed the PIC.
Controlling the FAST
The FAST is driven by 5vdc and draws approximately 25ma. The unit can be directly connected to a 5vdc power supply and the tube will run continuously. The FAST can also be driven by a variety of controllers. Examples of these are the Frank's Ren24LV, a Ren64XC with DCSSRs and the Ren48LSD. Note that the Ren48LSD was designed specifically for the purpose of driving Super Strips. The Ren64XC/DCSSR combination will work as well but it's a more expensive, larger and more cumbersome configuration to use but if you are driving other higher current DC devices, it can work fine. F.A.S.T (Finally Affordable Snowfall Tube)
BOM
From Mouser:
| Qty | Part Number | Description |
|---|---|---|
| 1 | 1-390261-3 | IC & Component Sockets 14P ECONOMY TIN |
| 1 | PIC16F688-I/P | Microcontrollers (MCU) 7KB 256 RAM 12 I/O |
| 8 | 299-51-RC | Carbon Film Resistors - Through Hole 51ohms 0.05 |
| 1 | 80-C322C104K5R | 0.1uF Capacitor Multilayer Ceramic Capacitors |
In addition, you will need up to 56 White Piranha Style Super flux LEDs. Other colors could be used, but you may need to adjust the resistor values on the controller board.
The FAST needs to be placed in a housing for display. A common fluorescent tube protector which is available from Home DepotHome Depot or Lowes works well. A similar tube is available in quantity from McMaster Carr
During the 2011 Fall Group Buy a Hanging End Cap was available.
PCBs
FAST Controller PCB
FAST LED Segment PCB
Assembly Instructions
TBD
Schematic
TBD
Firmware
The firmware is under development. If you are interested in helping add features, please contact chelmuth The current version is available here. File:FAST With Tail (Modular Wiring) 20110804.asm
FAST Discussion Threads
Original Thread
Interest Thread
Group Buy Thread