If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #347
Joined: Sat Mar 25 2006, 08:26AM
Location: Vancouver, Canada
Posts: 106
I just recently completed building a high speed camera (well, got it to a working state so far), see the thread over on the projects board. The camera can record 640x480 @ 250fps, and lower resolutions at higher frame rates, eg 320x240 @ 940fps. Record time is limited to about 0.9sec by the 64MB of ram on the FPGA development board the camera is based on, but that is sufficient for recording most events.
I don't have too much electrical stuff set up to record at the moment, I do have a compressed air gun set up, so most of the videos I have now involve that. I did record a Jacob's ladder though.
To frame through these videos precisely, I recommend playing them in VitrualDub.
Jacob's ladder (3.8MB, XviD) Record mode: 150x480 1040fps, probably 1ms exposure time, playback rate 20fps Lighting: Room lights only
Simple Jacob's ladder made with a 15kV 60mA NST. 14AWG wires about 20cm tall. Note the difference in brightness between the two ends of the arc, and how it changes each half-cycle.
This next set of videos involves shooting various things with a compressed air gun. The gun consists of a ~1.5l fire extinguisher tank pressurized to 400PSI with an air conditioner compressor. The air is discharged through a fast opening 3/4" ball valve into a 3/4" dia. 3m long barrel. It fires a 91g projectile at 150m/s (550km/h).
The valve opens in about 10mS, and the projectile is in the barrel for about 30ms after the valve starts opening.
Shooting bottles full of water (800kB, XviD) Record mode: 320x240 940fps, exposure time ~200uS, playback rate 10fps Lighting: 4 x 500W halogen
If you frame through the video, one frame shows the left bottle bulging out from the pressure created by the projectile pushing the water. This is seen more clearly in the next video.
Shooting 2l bottle very high speed (137kB, XviD) Record mode: 132x60 7645fps, exposure time 41uS, playback rate 10fps Lighting: 4 x 500W halogen about 30cm from the target
Similar to the above shot, but with a 2l bottle, and at a much lower resolution to get a higher frame rate. I notice some flashes at the bottom of the bottle just after the bullet goes by. It might be some sort of sonoluminescence, but it's probably just the lights reflecting the off the crinkling bottle. What do you guys think?
Shooting PS, CD, Floppy drive (1MB, XviD) Record mode: 256x120 2273fps, exposure time 191uS, playback rate 15fps Lighting: 2 x 500W halogen
Shooting old broken computer components, a power supply, CDROM and floppy drive. I was surprised that the projectile made it all the way through.
Shooting PS board (1MB, XviD) Record mode: 120x48 10101fps, exposure time 89uS, playback rate 10fps Lighting: 4 x 500W halogen as close as I dared put them
Shooting a blown "400W" (Yeah, right, that thing would barely handle 150W) power supply board. Very high rate, over 10,000fps.
Popping water balloon (3MB, XviD) Record mode: 160x320 1404fps, exposure time 260uS, playback rate 30fps Lighting: 500W halogen about 30cm away
Interesting mushroom cloud effect in this one, only the top section of the balloon popped, squirting water out upwards.
Popping air and water filled balloon (2.5MB, XviD) Record mode: 160x240 1812fps, exposure time 200uS, playback rate 30fps Lighting: 500W halogen about 30cm away
Breaking a Record (4.3MB, XviD) Record mode: 320x240 940fps, exposure time ~200uS, playback rate 10fps Lighting: 2 x 500W halogen
A record mounted on a angle grinder, shot with the compressed air gun at low pressure to cause it to shatter.
A 18AWG wire being flipped from pointing down to pointing up by magnetic forces.
Water discharge 1 (2.5MB, XviD) Record mode: 100x240 ~3000fps, playback rate 15fps
A jam jar filled with water, with two 18AWG wires connected to the cap bank touching lightly underwater. The mechanical shock breaks the glass bottle and sends water flying up to the ceiling.
Water discharge 2 (4MB, XviD) Record mode: 320x240 940fps, playback rate 15fps
Same as above, but different resolution and with a plastic bottle. Notice the cavitation generated just after firing (view frame by frame).
Water discharge 3 (1.8MB, XviD) Record mode: 180x320 ~1500fps, playback rate 15fps
Wires touching under a small amount of salt water. Water flies up very fast, maybe 200km/h.
Registered Member #53
Joined: Thu Feb 09 2006, 04:31AM
Location: Ontario, Canada
Posts: 638
That spot is visible in a lot of JL pics as along as they have a lot of current going through them. I think it has to do with the positive end of a very hot arc emitting positive ions (copper from pipe or iron from steel wire). So it is a cloud of ionized metal from the JL rails. (See below)
Registered Member #1025
Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566
Hi David, your job you have done is excellent. Please try to think about a possibility to sell your camera either as a "do it yourself kit" or as a completed product (with or without optics and casing). I have a serious interest and maybe more people would be interested too.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
High-speed Videos
