Another DIY Dimmer

[JonnyMac]

I designed an eight-channel dimmer for my Nuts & Volts column; complete plans and source code can be found in the November issue of Nuts & Volts magazine. The system can be scaled to 128 channels as each board has a 4-bit address switch. Connection to the PC is via RS-485 (one-way) over a CAT-5 cable.

The controller uses the Parallax SX processor, and is coded in SX/B with a bit of assembly in the ISR. It should be quite easy for anyone with a little coding experience to modify.

Here's a photo of my prototype:

http://www.efx-tek.com/files/jwlc.jpg

[Mudsculpter]

Introducing our next PCB designer,... New guy Johnny Mac. Looks nice. I'll bet you could compact it a bit more. (but leave room for a vixen logo)

I had an idea,... The way you have the triacs oriented,.... One could run a hollow rod through the holes in the triacs and provide a compact cooling method.

[JonnyMac]

The ExpressPCB files are in the ZIP, Chuhck -- have at it!

[AI]

I designed an eight-channel dimmer for my Nuts & Volts column; complete plans and source code can be found in the November issue of Nuts & Volts magazine. The system can be scaled to 128 channels as each board has a 4-bit address switch. Connection to the PC is via RS-485 (one-way) over a CAT-5 cable.

The controller uses the Parallax SX processor, and is coded in SX/B with a bit of assembly in the ISR. It should be quite easy for anyone with a little coding experience to modify.

Here's a photo of my prototype:

http://www.efx-tek.com/files/jwlc.jpg

Some how that dosnt look right, like an animation. AI

[grages]

I had an idea,... The way you have the triacs oriented,.... One could run a hollow rod through the holes in the triacs and provide a compact cooling method.

If you used a threaded rod you could put nuts on either side for good thermal contact and additional sink mass.

[DynamoBen]

Great article by the way.

[JonnyMac]

Some how that dosnt look right, like an animation. AI

I can assure you that's a real PCB that really works when driven by Vixen (or directly by a small microcontroller like the BASIC Stamp). I photographed it in diffuse light (to prevent shadows) against a piece of curved craft foam so I had a neutral background. Had it been a 3D model I would have made it look more like a production PCB with soldermask and labels -- as you can see, it's a raw PCB (you can even see the bottom ground plane through the board).

[AI]

Some how that dosnt look right, like an animation. AI

I can assure you that's a real PCB that really works when driven by Vixen (or directly by a small microcontroller like the BASIC Stamp). I photographed it in diffuse light (to prevent shadows) against a piece of curved craft foam so I had a neutral background. Had it been a 3D model I would have made it look more like a production PCB with soldermask and labels -- as you can see, it's a raw PCB (you can even see the bottom ground plane through the board).
Vary nice pic. Do you have a copy of the article? AI

[klanger]

Introducing our next PCB designer,... New guy Johnny Mac. Looks nice. I'll bet you could compact it a bit more. (but leave room for a vixen logo

Just enough room between the RJ45's and the chip for the Vixen logo :)

[henry_xmas]

Thanks Johnny Mac

I built the board and am playing around with them. :D :D

[daviddth]

Just enough room between the RJ45's and the chip for the Vixen logo :)

Darn, I have Vixen on the controller in 2 places, and now my lovely wife bought me a hat and shirt with "LIGHTS POWERED BY VIXEN" on it. I wore the cap on the TV last night during my interview lol

Next year I'll redesign my controller to fit a Vixen logo on the inside, and maybe one of these boards for fun ;)

[JonnyMac]

Very nice pic. Do you have a copy of the article? AI

Parallax hosts reprints of my column (since I write about their micros) but they haven't put the November issue up yet. You'll find it here when it does go up:

http://www.parallax.com/Resources/NutsVoltsColumns/NutsVoltsVolume8/tabid/451/Default.aspx

... or you can contact Nuts & Volts (www.nutsvolts.com) for an electronic issue. BTW, I have an ad hoc (i.e., not part of my normal column) article in the December issue of Nuts & Volts called "Vixen Lights the Way."

[Macrosill]

So you are Jon Williams!

[henry_xmas]

Mr Williams
I not sure if I am missing something or not but I built the board from the nuts and volts article. They seem to check out but I can't get them to do anything . One thing that I noticed in the schematics is that there is a resonator listed but, no such device on the parts list ,could that be the problem.

[DynamoBen]

One thing that I noticed in the schematics is that there is a resonator listed but, no such device on the parts list ,could that be the problem.

That could be a problem, that means the microcontroller isn't running...hence nothing happening.

[AI]

The nice pic from Mr Williams shows one on the bd. by the micro, the light blue thing. AI

[DynamoBen]

I grabbed my Nov issue of nuts and volts and it appears that the resonator that is in the pics and schematic didn't end up in the parts list.

[JonnyMac]

Hmmm.... I though I had the resonator listed in the parts list I submitted to Nuts & Volts -- forgive me since it's clearly not there (I just found the magazine and checked).

It's 50 MHz; you can get them from Parallax (250-05060 (http://www.parallax.com/Store/Microcontrollers/BASICStampModules/tabid/134/txtSearch/resonator/List/1/ProductID/360/Default.aspx?SortField=ProductName%2cProductName)) or EFX-TEK (350-05060 (http://www.efx-tek.com/topics/resonators.html)).

And if you're going to call me anything... 'Jon' is the preferred moniker; Mr. McPhalen (www.jonmcphalen.com) if you want to be formal -- but I'm not really a very formal guy, so let's stick to being friendly with first names, shall we? :D

[lightman]

Henry,

How did the boards turn out with the proper resonator?

I built one up and am having trouble getting it to slave to Vixen. I am using "Jon Wiliams Dimmer" plug in as specified in Vixen.

Do you have to run the board with RS485 or can it be connected with standard serial RS232 coming out of a Dell PC?

Regards,
Brian