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ZINOM
01-31-2008, 12:37 AM
I thought this clip was pretty neat....especially the low-light parts.

http://video.google.com/videoplay?docid=1427521026953606775&q=ho+scale+welder&total=2&start=0&num=10&so=0&type=search&plindex=0

John

Evan
01-31-2008, 04:11 AM
That is neat. A circuit that produces a realistic random appearing flicker isn't that simple. You generally need at least 4 light levels and and a fairly long shift register that is seeded with a somewhat random appearing source. The loaded value is then shifted along the register with the output feeding back to the input with some decode logic from intermediate stages being combined to vary the inputs bits. A couple of the stages are decoded to produce the minimum 4 light levels.

Not all feedback schemes work. Most result in a quickly repeating pattern. The maximum non repeating cycle length is equal to the nth power of 2 -1 where n is the number of stages.

macona
01-31-2008, 04:25 AM
There are all sorts of circuit boards available to do effcts and sounds for all sorts of models. A friend built a scale tug and when you start it it has diesel engine sounds and smoke starts coming out of the stacks. also sound varies depending on throttle position.

Heres the board that guy made for his welder:

http://modeltrain.servehttp.com/layout.nsf/1/welder-simulator

Couple others:

http://ittproducts.com/hqarcwelder.htm
http://www.modeltrainsoftware.com/welding.html

But this one seems to be the best. Seems this guy can actually hold an arc!

http://www.bakatronics.com/shop/item.asp?itemid=495