Ring Launcher
Part Scavenger, Sun Sept 10 2006, 02:20AMA fun project for the weekend, I started quite some time back and never got around to finishing it. I finished her this afternoon. The aluminum ring is from a hard drive, the post from a printer, the brass rings on the voltmeter are actually shotshells. The wood is white oak from a tree that was in our backyard. It silently launches the ring about three feet in the air. Came out looking rather sharp I think. There is a guy at an alternator shop who is saving wire for me, I built this (in part) so I could show him something I did with his wire.
Enjoy.
Re: Ring Launcher
ragnar, Sun Sept 10 2006, 03:54AM
Wow... that's really, really nice. I recognised the shotgun shells around the LEDs, they are SO charming!!
Beautiful work on the box-edges, too!
ragnar, Sun Sept 10 2006, 03:54AM
Wow... that's really, really nice. I recognised the shotgun shells around the LEDs, they are SO charming!!
Beautiful work on the box-edges, too!
Re: Ring Launcher
Alex, Sun Sept 10 2006, 04:46AM
Very nice! A good example of what attention to aesthetics and detail can do to an otherwise average project. Well done.
Alex, Sun Sept 10 2006, 04:46AM
Very nice! A good example of what attention to aesthetics and detail can do to an otherwise average project. Well done.
Re: Ring Launcher
Avalanche, Sun Sept 10 2006, 10:51AM
Nice, I like the woodwork there!
Those shotgun shells add a nice touch, I might have to 'borrow' that idea for things like headphone sockets and switches as well
Avalanche, Sun Sept 10 2006, 10:51AM
Nice, I like the woodwork there!
Those shotgun shells add a nice touch, I might have to 'borrow' that idea for things like headphone sockets and switches as well
Re: Ring Launcher
Marko, Sun Sept 10 2006, 01:29PM
Very nice box!
A TC built in similar one with those shell leds may be be even more gorgeous
PS. just saw avalanche's coil looking somewhat like such..
Marko, Sun Sept 10 2006, 01:29PM
Very nice box!
A TC built in similar one with those shell leds may be be even more gorgeous
PS. just saw avalanche's coil looking somewhat like such..
Re: Ring Launcher
Part Scavenger, Sun Sept 10 2006, 04:59PM
Thanks! It's a big hit with my sisters too, they've been playing with it all morning. I guess I should give some credit to my dad. He cut and glued the box together, but he's never interested in finishing them for some reason. That's always my job.
Part Scavenger, Sun Sept 10 2006, 04:59PM
Thanks! It's a big hit with my sisters too, they've been playing with it all morning. I guess I should give some credit to my dad. He cut and glued the box together, but he's never interested in finishing them for some reason. That's always my job.
Re: Ring Launcher
Avalanche, Sun Sept 10 2006, 05:38PM
hehe yes I posted my SGTC not long after seeing this, because it looked so similar. You win with the case though, it has a much nicer construction and finish than the one I built...
Avalanche, Sun Sept 10 2006, 05:38PM
hehe yes I posted my SGTC not long after seeing this, because it looked so similar. You win with the case though, it has a much nicer construction and finish than the one I built...
Re: Ring Launcher
Marko, Sun Sept 10 2006, 05:46PM
Doh, I should have competed with my ATX DRSSTC electronics-shielding for the ugliest box
For curiosity, you didn't describe is it just a thompson launcher or you have caps in it, or both
(wondering because of all that leds in front)
Marko, Sun Sept 10 2006, 05:46PM
Doh, I should have competed with my ATX DRSSTC electronics-shielding for the ugliest box
For curiosity, you didn't describe is it just a thompson launcher or you have caps in it, or both
(wondering because of all that leds in front)
Re: Ring Launcher
Part Scavenger, Sun Sept 10 2006, 11:31PM
Well, I don't really know any difference between any launchers. I didn't really do any research at all on the topic. I just remembered seeing one in the science museum, and spent about 30 min figuring out how it worked. Basically, I have a voltage doubler feeding a 400V, 470uF 'lytic. I then dug out an SCR, found out what it's pulse rating was, and designed the inductor accordingly. Actually, I could have gotten by with far better performance, but I didn't really want it to shoot 6' in the air, so I added some more inductance. A smarter way would have been to get a smaller cap I guess, but at that point the inductor was the easiest thing to change. BTW, there is a huge decrease in performance between a mechanical switch and the SCR.
The voltmeter is basically a divider that reads the voltage across the cap and feeds into an LM324 which, in turn, lights the leds.
If I can ever get around to it, I was planning to put the schematic, PCB's and some gut pics on my site, but unless there's demand I probably won't do it any time soon.
EDIT: Here's the PCB's though.
Part Scavenger, Sun Sept 10 2006, 11:31PM
Well, I don't really know any difference between any launchers. I didn't really do any research at all on the topic. I just remembered seeing one in the science museum, and spent about 30 min figuring out how it worked. Basically, I have a voltage doubler feeding a 400V, 470uF 'lytic. I then dug out an SCR, found out what it's pulse rating was, and designed the inductor accordingly. Actually, I could have gotten by with far better performance, but I didn't really want it to shoot 6' in the air, so I added some more inductance. A smarter way would have been to get a smaller cap I guess, but at that point the inductor was the easiest thing to change. BTW, there is a huge decrease in performance between a mechanical switch and the SCR.
The voltmeter is basically a divider that reads the voltage across the cap and feeds into an LM324 which, in turn, lights the leds.
If I can ever get around to it, I was planning to put the schematic, PCB's and some gut pics on my site, but unless there's demand I probably won't do it any time soon.
EDIT: Here's the PCB's though.
Re: Ring Launcher
Marko, Mon Sept 11 2006, 10:56AM
Is taht pole of metal or it's a wierd looking non-conducting stuff?
For plse launchers metal shaft would waste lot of energy unneedingly..
Marko, Mon Sept 11 2006, 10:56AM
Is taht pole of metal or it's a wierd looking non-conducting stuff?
For plse launchers metal shaft would waste lot of energy unneedingly..
Re: Ring Launcher
Part Scavenger, Mon Sept 11 2006, 11:12AM
Nope. It's steel I think, definitely ferrous. The reason it's there is because without it, I get big peak currents and the ring only just falls off the stand. I originally thought the same as you did.
Part Scavenger, Mon Sept 11 2006, 11:12AM
Nope. It's steel I think, definitely ferrous. The reason it's there is because without it, I get big peak currents and the ring only just falls off the stand. I originally thought the same as you did.
Re: Ring Launcher
Marko, Mon Sept 11 2006, 12:20PM
I tihik it falls from stand more because is simply loses balance (?).
Peak current can be minimized by adding more inductance, or lowering cap voltage in exschange for capacitance (use more capacitance and no doubler for example).
For your description just couple of 200V 470uF caps would work.
I would put something like PVC pipe in that place
Marko, Mon Sept 11 2006, 12:20PM
I tihik it falls from stand more because is simply loses balance (?).
Peak current can be minimized by adding more inductance, or lowering cap voltage in exschange for capacitance (use more capacitance and no doubler for example).
For your description just couple of 200V 470uF caps would work.
I would put something like PVC pipe in that place
Re: Ring Launcher
EEYORE, Mon Sept 11 2006, 05:30PM
I built one of these years ago. Used 500volt 3500uF lytics (2 of them for 500volts, 7000uF). I made a flat spiral coil with maybe 20 turns of like 12awg. I used the same ring as you did too. I just layed it on the coil, no rod to guide it. No scr would stand up to it, so I used metal rods to short, caveman style My ring would go up some 50 feet or more, very loud, and HURTS when it falls on one's head! Eventually, the coil broke from the power.
Matt
EEYORE, Mon Sept 11 2006, 05:30PM
I built one of these years ago. Used 500volt 3500uF lytics (2 of them for 500volts, 7000uF). I made a flat spiral coil with maybe 20 turns of like 12awg. I used the same ring as you did too. I just layed it on the coil, no rod to guide it. No scr would stand up to it, so I used metal rods to short, caveman style
My ring would go up some 50 feet or more, very loud, and HURTS when it falls on one's head! Eventually, the coil broke from the power.Matt
Re: Ring Launcher
Electroholic, Mon Sept 11 2006, 06:16PM
the rod is there to increase inductance and concentrate the flux, like coil gun, there should be a balance between them, and no one can tell you exactly how to achieve the highest efficiency.
Good job, very professional looking.
Electroholic, Mon Sept 11 2006, 06:16PM
the rod is there to increase inductance and concentrate the flux, like coil gun, there should be a balance between them, and no one can tell you exactly how to achieve the highest efficiency.
Good job, very professional looking.
Re: Ring Launcher
Marko, Mon Sept 11 2006, 06:43PM
Rod is truly a benefit for thompsn launcher (using continuous AC into coil to repel the ring).
Pulsed rgn-launchers can work well witrhout it too if tuned and souped up.
You can come to some serious disk velocities with few hundred joules of energy, but this one is fine as a small demonstrative launcher.
Marko, Mon Sept 11 2006, 06:43PM
Rod is truly a benefit for thompsn launcher (using continuous AC into coil to repel the ring).
Pulsed rgn-launchers can work well witrhout it too if tuned and souped up.
You can come to some serious disk velocities with few hundred joules of energy, but this one is fine as a small demonstrative launcher.
Re: Ring Launcher
Part Scavenger, Tue Sept 12 2006, 11:00PM
Just for the record, I couldn't get it to do hardly anything without the metal rod. I tried several types of coils and wire sizes but nothing worked. I did try a PVC core as well. With the same pulse that will shoot the ring about 6 feet in the air (metal rod) I can't get it to do anything without the rod.
So, if I wanted to get rid of the rod, what would I do differently?
Part Scavenger, Tue Sept 12 2006, 11:00PM
Just for the record, I couldn't get it to do hardly anything without the metal rod. I tried several types of coils and wire sizes but nothing worked. I did try a PVC core as well. With the same pulse that will shoot the ring about 6 feet in the air (metal rod) I can't get it to do anything without the rod.
So, if I wanted to get rid of the rod, what would I do differently?
Re: Ring Launcher
Electroholic, Wed Sept 13 2006, 09:53AM
i dont' think you can get rid of the rod, but you can probably get away with about 1/3 or even less than what you have right now.
Electroholic, Wed Sept 13 2006, 09:53AM
i dont' think you can get rid of the rod, but you can probably get away with about 1/3 or even less than what you have right now.
Re: Ring Launcher
Hazmatt_(The Underdog), Wed Sept 13 2006, 06:22PM
The rod doesn't need to be long because the field drops off as 1/r^2. So by the time the ring gets to the end of your rod it doesn't really feel much of an effect.
My tosser is around here somewhere, probably in the EM projectile thread. Anyway, I get 14' launch from ~160J with a 9" inverted Tee shaped tube. It's Tee shaped because I had to braze a washer to the back of the tube so I could mount it to the wood.
My first version was like yours, only firing in the vertical position. The newer model can be aimed for demonstrations in projectile motion.
My next step is to use an SCR to trigger the gun and to have it uC controlled to fire at 3 different voltages as a demo for kids. They will see how the energy greatly affects apogee in a vertically launched ring gun.
Also, my ring gun uses a hollow tube of steel. If you don't want to use a hollow rod, the best way to go is to fill a hollow tube with oxide coated rods of steel, just like a transformer. The oxide improves performace by reducing lossy eddy currents during the pulse.
Matt
Hazmatt_(The Underdog), Wed Sept 13 2006, 06:22PM
The rod doesn't need to be long because the field drops off as 1/r^2. So by the time the ring gets to the end of your rod it doesn't really feel much of an effect.
My tosser is around here somewhere, probably in the EM projectile thread. Anyway, I get 14' launch from ~160J with a 9" inverted Tee shaped tube. It's Tee shaped because I had to braze a washer to the back of the tube so I could mount it to the wood.
My first version was like yours, only firing in the vertical position. The newer model can be aimed for demonstrations in projectile motion.
My next step is to use an SCR to trigger the gun and to have it uC controlled to fire at 3 different voltages as a demo for kids. They will see how the energy greatly affects apogee in a vertically launched ring gun.
Also, my ring gun uses a hollow tube of steel. If you don't want to use a hollow rod, the best way to go is to fill a hollow tube with oxide coated rods of steel, just like a transformer. The oxide improves performace by reducing lossy eddy currents during the pulse.
Matt
Re: Ring Launcher
Part Scavenger, Wed Sept 13 2006, 11:16PM
You could do that pretty easily with this one. Just trigger the gate differently than I've got it. I've got a 8 step LM324 based voltmeter that I designed a while back if you want a better meter than this one. Funny, I think I'm finally getting to the point were I can just "build" whatever I want. Sometimes...
/*Digs up pic
Part Scavenger, Wed Sept 13 2006, 11:16PM
You could do that pretty easily with this one. Just trigger the gate differently than I've got it. I've got a 8 step LM324 based voltmeter that I designed a while back if you want a better meter than this one. Funny, I think I'm finally getting to the point were I can just "build" whatever I want. Sometimes...
/*Digs up pic
Re: Ring Launcher
Hazmatt_(The Underdog), Thu Sept 14 2006, 12:51AM
why would you do that?
the lm3915 is a bar/dot voltmeter in 1 chip!!
Hazmatt_(The Underdog), Thu Sept 14 2006, 12:51AM
why would you do that?
the lm3915 is a bar/dot voltmeter in 1 chip!!
Re: Ring Launcher
Part Scavenger, Thu Sept 14 2006, 09:56PM
Cause I don't have any of those and shipping is killer...
Part Scavenger, Thu Sept 14 2006, 09:56PM
Cause I don't have any of those and shipping is killer...
Re: Ring Launcher
ragnar, Fri Sept 15 2006, 01:20AM
They're pricey, too -- like $6 at my local Jaycar store...
I've fiddle with a few of them though, they're not bad. The LM3914/3915 are fun for VU meters. =-)
ragnar, Fri Sept 15 2006, 01:20AM
They're pricey, too -- like $6 at my local Jaycar store...
I've fiddle with a few of them though, they're not bad. The LM3914/3915 are fun for VU meters. =-)
Re: Ring Launcher
Steve Conner, Fri Sept 15 2006, 09:35AM
You used to be able to buy a commercial 20 LED bargraph meter kit that was totally made out of LM324s and resistors. I used to have a stack of 20 of the things with a huge display of about 400 LEDs, that I found while dumpster diving. I think it was someone's home-made audio spectrum analyser. I never got it to work though, I think the analysis filter bank was missing.
Steve Conner, Fri Sept 15 2006, 09:35AM
You used to be able to buy a commercial 20 LED bargraph meter kit that was totally made out of LM324s and resistors. I used to have a stack of 20 of the things with a huge display of about 400 LEDs, that I found while dumpster diving. I think it was someone's home-made audio spectrum analyser. I never got it to work though, I think the analysis filter bank was missing.
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