I know there are a couple of kits available on the web that provide a circuit for producing the flashing of an arc welder, but some of the videos of them are not all that encouraging.

Does anyone have a circuit that one can make up and twiddle resistor and capacitor values to achieve the desired effect of pauses and welding flicker?

I would imagine fairly decent pauses between welding - in the order of 20 seconds or so... and then welding light for intervals of 3 to 6 seconds?

The more 'random' the better.

Failing that, anyone have video of a kit that they think is perfect?

That doesn't too bad. At least I see some pseudo-random generator.
If it were me, I would just take a microprocessor and program the welding flicker (and random delays) in that. Less components and in full control of the result.

There are several different ways to go, simply because of different types of microprocessors available. These are separated into processor "families", and some of the smallest ones available (in terms of processing power) are AVR, PIC and 8051. Each of those could easily take care of this welding task.

If is was me, I would select an AVR. Not because it is better than the other families, but solely because I am already using them for various other projects.
The programming language is also selectable. Various compilers exist, so choose whatever you are comfortable with. You can make programs for the AVR in assembler, C, Basic, Pascal and so on, with assembler and C as the most common ones. The AVR is made by Atmel, and they provide the assembler development tools for free. Several C compilers exist, where the gcc compiler is free, while others cost quite a bit of money.
Lastly you will need a programmer to program the processor. The most simple form of that is a couple of resistors and a parallel port.

I could make a "welder" quite easily, as I have already made a generic LED controller program, to make nice light patterns on 16 outputs. I have used this in a small indoor water fountain:
http://www.ejberg.dk/ledfade2/
The LED outputs are controlled by a script, that is placed in the processor, and it can easily be changed to a welding flicker. The only thing I am missing is a random generator for the delay, but that wouldn't take me many minutes to write.

Well, it depends. You will need the chip, a 5V supply (that involves a regulator, but I guess you know all about those now), a resistor or two and either a 16 MHz ceramic resonator (with built-in capacitors) or a 16 MHz crystal plus two small capacitors.
If you can drive the leds from 5V and max 20 mA, then you don't need any more. If you need more output power, then another resistor and a transistor for each output is needed.


I might be able to be pursuaded, but then it will have to be perfect in the first attempt. I'd much rather that you build your own programmer, which I believe doesn't take much more than some resistors and a parallel port on a PC, but I'll have to look into that. Then I can send you the chip software, as well as the programming software, with the commands to run. In this case we can always make changes if needed, and who knows, you might even begin to make alterations to the program yourself



Yes, that is no problem at all.

great ! looking forward to it
you could put the clip on youtube and link to it there

also did you create a breadboard layout ?

I am still building my roundhouse but I would liek to place the welder in it, I guess I could build in the LED now and connect it up later...

great ! that worked !
I think I wil try this out !
I too wont need power regulation as I have a clean 12V Dc supply.

I found that the simplest way to build a single board is to buy
a handful of wire wrap dip sockets (machined type), a handful
of dip headers for soldering on components which plug into the sockets.
Pick up a hand wire wrap tool, a proto type circuit board,
and a few different colors of wire wrap wire. The layout
is determined by what looks best for mounting the components. Mark
the #1 pins on the back side as the mirror image work can drive you nuts.
For this project that pot can be replaced by a fixed resistor.
Don't worry about reliability, I've maintained a wirewrap based
system with many thousands of connections for over twenty years and
have yet to see an electrical failure of a properly wrapped pin.

Best wishes on your project,
-george

Here's the wire-wrap version: (my led looked best with the pot at zero ohms so I just left it out, I also sub'd a TIP-122 transistor)

cool video Dale