Homebrew HV & other 'junk'

Hi All...

Started this thread because I was starting to make the meet & greet thread a bit untidy - my apologies.

I have built some useful & some less useful devices in my time.
I guess most people with an engineering background have made a 'death ray', spud gun, Jacob's ladder, or to generalise an object with no meaningful function other than to make other engineers go Oooohh! or Ahhhhh!

My 12V CO2 laser rifle has a divergence of 13.5mrad so will eventually melt a hole in a chocolate teapot at 5 meters and is just about as useful.

With a big beam expander it might be made useful but that bit would cost more $$$ than the rest of the parts and that would be missing the point of the post.

So come on 'fess up an post details & pics of your 'useless' monstrosities.

Robin.

I made a Tesla coil a long time ago. There was an article in Radio Electronics magazine that showed how. It was very cool.

Most of my other stuff has been mechanical things like turning a self propeled push lawnmower to a little car (until the wheels fell off) or converting an electric golf cart into a gas powered redneckmobile.

Quote:

---

Originally Posted by carmangary

Most of my other stuff has been mechanical things like turning a self propeled push lawnmower to a little car (until the wheels fell off)

---

There are some great youtube clips of people who have added a turbo to their lawnmowers. Lots of blue smoke and the feeling it won't be long before a piston comes through the crank case.

Welcome aboard Robin :)

Ahh- lawnmowers, yes..
http://www.youtube.com/watch?v=zT60SkXN1UY

Here's one of my less useful devices... http://www.youtube.com/watch?v=mBZOZBzdLZ0

I like the jet powered beer cooler.

Quote:

---

Originally Posted by QUAZAR

I like the jet powered beer cooler.

---

Nice - but this one cools & delivers your beer.
http://www.youtube.com/watch?v=5gnC0gHERbI

http://www.lostgallifreyan.pwp.bluey...aser/BSL_1.jpg
http://www.lostgallifreyan.pwp.bluey...aser/BSL_2.jpg
http://www.lostgallifreyan.pwp.bluey...aser/BSL_3.jpg
http://www.lostgallifreyan.pwp.bluey...aser/BSL_4.jpg
http://www.lostgallifreyan.pwp.bluey...aser/BSL_5.jpg
http://www.lostgallifreyan.pwp.bluey...aser/BSL_6.jpg
http://www.lostgallifreyan.pwp.bluey...aser/BSL_7.jpg

The operative word is 'monstrosity'. And just possibly, 'useless'.

Cool Dr.. does it still work? Looked like a fun project to build:)

It puts out about 5 mW. It put out 20 mW once but such is life...

My hene puts out 7 mw. I need to get a power supply for it and get it back up and running. Its kinda neat even tho lo power.

Quote:

---

Originally Posted by steve-o

My hene puts out 7 mw. I need to get a power supply for it and get it back up and running. Its kinda neat even tho lo power.

---

But is it blue? >:) That's about the only thing that can be claimed for mine. I was asked to put it together in a week at lowest possible cost, using whatever could be found. Most of the crucial parts came from one source, but not all. Was one of the ten most busy weeks of my life, probably. It actually did shows, I controlled a Lissajous device at one of them. I was given the laser in the end, when the guy I built it for needed to move and find places to put stuff.

No its 632.8. I do have an argon that does blue 488nm 500:1 pol 30 mw though. Built from scratch (except the tube) Puts out about a KW of heat (good room warmer in the winter)

I finally found my most useless device...
http://www.youtube.com/watch?v=4iUASNmjcgo

LOL! That is so redneck! I was just waiting for the idiot to get shocked! Did you see the lamp hanging on the chair?

Laser Ben;

Um... You might want to re-phrase that... I think the "idiot" you refer to in the video is actually Steve-o, the guy who posted it. And I don't really think he qualifies as an idiot. The light on the chair is probably positioned so that the video camera had enough light to shoot in the otherwise dark room. (Without sufficient ambient light the auto-iris on the camera would close down too far once the arc was lit and you'd never see anything else in the picture.)

Personally I think a home-made arc lamp is a cool project. Somewhere between a souped-up-flashlight and a Jacob's ladder on the coolness scale. And I'm sure the end of that rod he was touching was either insulated or at ground potential... Either way, give the guy some credit man...

Though I gotta admit that the narrator (I assume it's you, Steve-o?) sounds like he just woke up... Maybe it was after toddy time following a really long day.?. :D

Hey Steve-o! How about you bring that sucker to SELEM, dude!?!

Adam

Quote:

---

Originally Posted by Buffo

Personally I think a home-made arc lamp is a cool project. Somewhere between a souped-up-flashlight and a Jacob's ladder on the coolness scale.

---

Hell no, I think a home made arc lamp scores above a Jacob's Ladder. I made a Jacob's Ladder and it was disappointing. It worked, but once that was done what else was there? Arc lamps are cool. And for redneck, can there be much more rustic than that horrible argon I built? I thought it looked like the locomotive of a 125 train at the time. The friend I built it for thought it looked like a rabbit hutch. It didn't take me long to see it his way.

Doc;

A rabbit hutch! Damn, you're absolutely right - that's exactly what it looks like! hehe! What the hell though; it got the job done, didn't it? :D I've put together some ghetto-looking projects in my time as well. All part of the learning curve, right? ;)

Re: Jacob's Ladder - eh, I guess I've always wanted one, which is why it's so high on the list for me. But you have a good point: Once you build it there's not much else you can do with it. But they sure look cool.

Adam

Quote:

---

Originally Posted by Buffo

Re: Jacob's Ladder - eh, I guess I've always wanted one, which is why it's so high on the list for me. But you have a good point: Once you build it there's not much else you can do with it. But they sure look cool.

Adam

---

This is true, they do. Mine was poxy though, couple of bed springs on a bit of old doorframe holding tight some 2.5 mm² copper wire. The wood ended up burning... So there is one thing we can always do: build bigger, and better. And pretend to be Tesla. >:)

HA!! Yeah the idiot's me, and Adam-you nailed it right on the head! Long day, toddy time -but I finally remembered my "most useless device" so had to put it up right then b4 I forgot. Dr- I think your rabbit-hutch-argon is great:) and a Jacobs ladder is waycool too. No 1950s sci-fi movie would be complete w/o one:D

Quote:

---

Originally Posted by steve-o

I finally found my most useless device...
http://www.youtube.com/watch?v=4iUASNmjcgo

---

Hey Steve,
Cool project. I have always wanted to build one of these. I couldn't find any schematics on instructions on the net. It's basically an inductor, a rectifier, some caps and two carbon rods right? Any info you can supply would be most appreciated.
Thanks!
Adam

Thanx Adam
I'll put up a schematic.

More junk - the desktop Jacob's ladder.
Think I could get light out of a pair of carbon rods with it though.
http://www.die4laser.com/D4Sparks/Jacobs_ladder.mpg

That's COOL:D.................................................. ..

Wow! The arc really moves fast on that one! What affects the speed? Can you slow it down or speed it up, or is it a fuction of the design? (Or the spacing of the rods?)

Very cool though!

Adam

Nice, a flyback transformer? Useful thingers, methinks. Buffo, I think the rod angle might have some effect but it's mostly heat, the arc rises with its own heat till it breaks. Changes in conductivity can anchor an arc for a while, as that clip shows. My first attempt had that problem so bad the arc wouldn't rise. Clean polished metal with no bumps in it helps, and bulk to conduct heat away especially if your source has a high current. I guess choice of metal can affect arc colour, but I haven't made enough to know.

Erm - I didn't look too closely into the physics.
I had just built a ZVS driver for the flyback transformer and once you have tested it by drawing your first arc there is only one thing left to do ;-)
The speed is likely the result of the power going into the arc - the better part of 100W at its highest point & also the waveform being high frequency. (Actually high frequency pulsed DC - you note the arc rise is asymmetric between the two electrodes - one favors climbing)

Quote:

---

Originally Posted by uk-laser

(Actually high frequency pulsed DC - you note the arc rise is asymmetric between the two electrodes - one favors climbing)

---

That's interesting. Any chance you can rig one to reverse polarity to see if the arc swaps to favour the other end? Power in means heat, the rise is based on that I think, so as current is equal at all points in the arc unless the density/volume is different at one end, this apparent polarity is weird. It implies chemical reaction, so you might need to renew metal surfaces to retest each time by a bit of Brasso or such.

Quote:

---

Hey Steve,
Cool project. I have always wanted to build one of these. I couldn't find any schematics on instructions on the net. It's basically an inductor, a rectifier, some caps and two carbon rods right? Any info you can supply would be most appreciated.
Thanks!
Adam

---

Here ya' go Adam,
The gap is (2) 1/4-20 grade 8 bolts spring loaded to contact then release.
They glow red hot after 30 sec or so:) and they do disintegrate and shorten after used for a while.
Now if I could just figure out how to make this thing lase...;)

<edit>
To be on the safe side you should really go with a 40 Ohm 600 Watt resistor instead of 200W. I just did a re-calculation.
I used what I had laying around and i take chances (+ I dont leave it on very long, and it smokes too and I dont know what's in that smoke.) I may add that to the pic. Also make the caps 1000uF instead of 330 (another re-calc)
Also, should probably wear safety glasses (just thought of that.) Hind-sight is 20/20..

Hi Steve,
Thanks a lot for the info! Is there a particular reason you didn't use carbon electrodes? I hear the carbon rods found in Alkaline C cells work best. All I need now is a 600W resistor and I'm all set.
Thanks Again!
Adam

I didnt know about this until I built one. I'll have to try carbon rods!