Holiday

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Welcome. This is my web page supporting the November 2000, Holiday Light Dimmer article in Nuts and Volts Magazine.

Download Files
Construction Details
Parts List
Order Parts
Links to DMX512 sites

The article describes the basics to build a lighting dimmer using an 8031 microcontroller. Assembly language examples are given.
Click here to see the article in PDF format

The circuit board and parts offered are an enhanced version of the board that appeared in the Nuts and Volts article. The software allows the dimmer to be controled by the DMX 512 lighting dimmer protocol. This is standard for stage lighting dimmers. The software will automaticly detect the presence of DMX 512 and respond to DMX only. If DMX is not present the dimmer will resume the preprogrammed fades.
The board has address selector switches that allow a starting address from 1 to 64.
Limitations: The software cannot recieve over 256 dimmer channels. This is not usually a problem as most small amd medium lighting boards don't controll that many channels anyway.
If you order the pc board, the mounting and front label are slightly different from the Nuts and Volts article. I will email a new zip file when the order is placed.
For more information on DMX 512 check the links at the bottom of the page.

Click here to download a zip file with all.
List of files in ZIP download. These are the same files on the Nuts and Volts web site.
Nv51-4.bin          Compiled code binary file, 0 offset, from Nuts and Volts article
Nv51-4.hex         Compiled code Intel hex file from Nuts and Volts article
Wave51-4.bin      Compilede code with DMX 512
Wave51-4.hex     Compiled code with DMX 512
nvlabel.tif              Front panel label Tiff format, actual size, print at 300 DPI
nvpcb.tif               Pcboard pattern Tiff format, actual size, print at 300 DPI
nvschem.tif           Schematic of Holiday light dimmer, print at 300 DPI
nvsilk.tif                Parts placment , actual size, print at 300 DPI
partlist.txt              Parts list for Holiday light dimmer

Construction:
About the pcboard pattern. I have printed the pc board pattern using Corel Draw and Adobe Photo Deluxe. Print at 300 DPI. Don't bother to use MS paint. The board measures 3" X 4". If for some reason yours dosen't print out to those dimensions you'll have to scale to image.

Making the PC board

This is the finished prototype PC board.
I used a Kepro systems presensitised board. This is a negative system. I used the "invert" function of my pc board layout program to print the pc pattern on clear film for laser printers. Since the laser print is not as dense as a film negative you'll want to keep the exposure time to a minimum. I have had good sucess using this method. If your laser printed has adjustments for print density, the HP laserprinters do, set density for max.
I did try to this with a Epson color inkjet on clear film for inkjet printers. The results were dissapointing. The ink simply wasn't dense enough. However you could print the pattern on paper, then zerox on to clear film.

Installing the board

The boards are arranged in a stack for mounting. Use male/female standoffs.
The cover does not need to be metal. I buy pc board laminate from a local surplus house. This works great for all sorts of uses, is easy to cut and very durable.
The label is spray glued to the top cover with 3M Super 77 adhesive. This glue is very tough.
Note the voltage regulator and triacs are mounted on the solder side of the board.

The whole thing, without the label cover, mounted in a weatherproof 6X6X5 J box.

Parts List

Parts List - Parts fit example circuit board

D0 Diode Bridge           ; Digi-Key part DB101MS-ND
D1 1N4001 Silicon Diode
C0 350uf 16volt electrolytic
C1 10uf electrolytic
C2 100 electrolytic
C3 .01 ceramic disk
C4     1 uf electrolytic
C5,C6 22pf ceramic disk
C7-C10 .01 Polypropolene, 250 volt
R0     3.3K ¼ watt
R1 10K   ¼ watt
R2 10K   ¼ watt
R4 10K   ¼ watt
R11-14 180   ½ watt
R15-18 100 ½ watt
R15-16 22K PC Mount trim RadioShack.com 900-5940
R17 470 SIP resistor         &nb sp; Digi_Key part EXB-F6E471G-ND
Q1,Q2 2N3904 NPN
U1 LM7805 Voltage regulator
U2 ADC08032 Analog to digital converter
U3 AT89c2051 microcontroller
U4-7   MOC3010 triac driver optoisolator
T1-4 6 Amp triac, isolated tab
Sw-1   Rotary dip BCD switch   Digi-Key part sw214-ND
TB1-4 Screw Terminal Block 5MM lead spacing
X1 Xtal 16 MHZ low profile    Digi-Key 300-6034-ND
3 - Knobs for trim pots
19mm shaft for trim pots       RadioShack.com 900-5964
4 - .250" Hex male/female standoff .50" length
4 - .250" Hex male/female standoff 1.50" length

Contact author at NorthlightSystems@att.net

Links: More info on DMX 512

Click here for a general description of DMX 512 protocol.

Click here for RS-485 guidlines.