Author Topic: Global shutter synchronized to arcs?  (Read 1149 times)

Offline davekni

  • High Voltage Expert
  • ******
  • Posts: 1899
  • Karma: +95/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Global shutter synchronized to arcs?
« on: July 19, 2021, 06:32:35 AM »
Just a thought at this point.  Does anyone have a global-shutter camera?  It would be interesting to sync the camera exposure with DRSSTC sparks.  With a properly timed and short exposure it should be possible to get good arc images in brighter background situations.  Synchronized global-shutter video could allow daytime DRSSTC testing while still monitoring for errant sparks.

Two possibilities for synchronizing.  The likely-easier option would be to use a camera output intended for strobe-light triggering to trigger single DRSSTC enable pulses.  The down-side of this option is longer exposure times (unless the camera has an option to generate a trigger slightly prior to shutter opening.)

The other possibility is to trigger camera exposure from the DRSSTC enable pulse, perhaps with some controlled added delay.  Then the exposure could be short, covering just the active arc portion of the DRSSTC pulse.

I've built similar systems at work for strobed microscope viewing of ink drops.  Unfortunately, I don't think there's any equipment available to borrow.  I see cheap (~$70) global-shutter webcams from China.  Can't find any information about options for trigger input or strobe output.  The cheapest global-shutter camera I've found that lists trigger capability is $200+shipping.  Perhaps someday when my project list gets short ;) I'll buy a camera and experiment.  That is if no one else has tried it first.
David Knierim

Offline klugesmith

  • High Voltage Senior
  • *****
  • Posts: 557
  • Karma: +18/-0
    • View Profile
Re: Global shutter synchronized to arcs?
« Reply #1 on: July 19, 2021, 06:49:08 PM »
Nice idea there.
I bet a typical visible arc is the sum of many DRSSTC pulses following the same ionized air channel, as with natural lightning.   Maybe the first pulse is not the brightest.

Do global shutter digital cameras allow independent control of the shutter duration?

Using camera shutter as the master, to trigger the DRSSTC as it might trigger an electronic flash,
would work even with a film camera.  Many film cameras have global shutter times down to 1/500 second, with flash trigger at beginning of the wide-open time.

Offline TMaxElectronics

  • High Voltage Engineer
  • ****
  • Posts: 250
  • Karma: +15/-0
    • View Profile
    • My random (and very empty) electronics blog
Re: Global shutter synchronized to arcs?
« Reply #2 on: July 20, 2021, 12:09:36 AM »
I guess the easiest way would be to trigger them the way flashes are triggered. Not quite sure why that should result in longer exposure times though. You can still adjust all parameters in full manual mode. And the few 100 microseconds probably don't make too much difference either I'd guess.

The camera flash approach could actually be really easy, just a monostable 555, a photodiode and an IR filter from a remote control or something like that. I remember some of the old photo-flashes detecting the main flash like that, without requiring a special emitter on the camera. I'm assuming they just look for the IR pulse from the flash tube of the camera.

Offline davekni

  • High Voltage Expert
  • ******
  • Posts: 1899
  • Karma: +95/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: Global shutter synchronized to arcs?
« Reply #3 on: July 20, 2021, 04:43:05 AM »
Quote
I bet a typical visible arc is the sum of many DRSSTC pulses following the same ionized air channel, as with natural lightning.   Maybe the first pulse is not the brightest.
Yes, I'm confident you are right.  With high detuning, the first few pulses make very short weak arcs.  That shows up in scope measurements and sequential video frames.  Also, each pulse's arc generally displaces slightly from the previous path due to air motion - showing up as beautiful parallel paths in images.  Having the DRSSTC electronics trigger camera exposure would allow triggering on the Nth pulse where the arc is strong (presuming smart electronics).

Quote
Do global shutter digital cameras allow independent control of the shutter duration?
Not certain I know what "independent" means here.  The cameras we use at work have options for either programmed exposure time started by an edge of an external signal or for exposure to match the width of the external pulse.

The ideal (in my mind) camera would allow multiple short exposures with independent control of exposure (shutter open and close) and when the exposure-generated charge is transferred to readout circuitry (CCD cells or CMOS capacitors).  That would allow multi-arc images.  Would be useful at work too.  However, the global-shutter cameras I've seen always transfer charge at the end of the exposure window, with no separate control.

Quote
Not quite sure why that should result in longer exposure times though. You can still adjust all parameters in full manual mode. And the few 100 microseconds probably don't make too much difference either I'd guess.
Exposure times are longer because exposure starts (slightly) before DRSSTC pulse starts.  The arc doesn't start until primary current has built up and a significant fraction of primary energy transferred to secondary.  Starting exposure as or after the arc forms allows shorter exposure.  Daytime is very bright.  It will require short exposures to not swamp arc light with daylight.  Longer (but still short) exposures would be useful closer to dusk when daylight is lower.

Quote
The camera flash approach could actually be really easy, just a monostable 555, a photodiode and an IR filter from a remote control or something like that. I remember some of the old photo-flashes detecting the main flash like that, without requiring a special emitter on the camera. I'm assuming they just look for the IR pulse from the flash tube of the camera.
Yes, I agree, the camera flash approach is easier.  Just more limited.
David Knierim

Offline Uspring

  • High Voltage Engineer
  • ****
  • Posts: 317
  • Karma: +31/-1
  • Physicist
    • View Profile
Re: Global shutter synchronized to arcs?
« Reply #4 on: July 21, 2021, 05:10:18 PM »
Quote
With high detuning, the first few pulses make very short weak arcs.
IIRC, the first 2 or 3 bursts of a longer sequence in Hydrons measurement https://highvoltageforum.net/index.php?topic=117.msg735#msg735 showed a considerably higher arc voltage and a bit lower arc current compared to the later ones. Higher voltages and lower currents likely imply a lower capacitance, so probably shorter arcs and possibly less bright ones. A dependency on the tuning conditions seems quite plausible.
Quote
The ideal (in my mind) camera would allow multiple short exposures with independent control of exposure (shutter open and close) and when the exposure-generated charge is transferred to readout circuitry (CCD cells or CMOS capacitors).
The CCDs I used to work with (long time ago) only had a single charge path from the photo sites. This went to the analog shift register. For a multiply shuttered exposure, you'd need to dump photo electrons somewhere else for the unwanted exposure time. The CCDs I remember did not have a path for this.

High Voltage Forum

Re: Global shutter synchronized to arcs?
« Reply #4 on: July 21, 2021, 05:10:18 PM »

 


* Recent Topics and Posts

post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
klugesmith
Today at 09:35:18 AM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
DashApple
Today at 07:37:22 AM
post Re: UD2.7 onwards - post-2014 changes published anywhere?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
Today at 05:17:26 AM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
davekni
Today at 04:51:33 AM
post Re: Slayer exciter circuit - struggling with how it works
[Solid State Tesla Coils (SSTC)]
Twospoons
Today at 04:43:37 AM
post [WTB] IF D95T / IF D95OC optic receiver
[Sell / Buy / Trade]
RoamingD
November 29, 2022, 10:23:35 PM
post Re: UD2.7 onwards - post-2014 changes published anywhere?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
November 29, 2022, 09:14:10 PM
post UD2.7 onwards - post-2014 changes published anywhere?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
AkashaStar
November 29, 2022, 07:32:37 PM
post 8000FPS Slow Motion Tesla Coil Spark Formation and Collapsing Hot Spots
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
November 29, 2022, 05:21:49 PM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
alan sailer
November 29, 2022, 04:08:00 PM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
kurtrox
November 29, 2022, 05:51:59 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 29, 2022, 01:25:43 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Twospoons
November 28, 2022, 10:09:56 PM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
Uspring
November 28, 2022, 06:01:14 PM
post Slayer exciter circuit - struggling with how it works
[Solid State Tesla Coils (SSTC)]
Tatranka
November 28, 2022, 02:57:17 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 28, 2022, 11:38:26 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
klugesmith
November 28, 2022, 11:22:51 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 28, 2022, 05:55:16 AM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
klugesmith
November 28, 2022, 05:21:37 AM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
davekni
November 28, 2022, 03:26:55 AM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
klugesmith
November 28, 2022, 02:09:06 AM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
alan sailer
November 28, 2022, 12:06:02 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
klugesmith
November 27, 2022, 06:05:52 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 27, 2022, 01:24:05 PM
post Re: ZVS driver won't oscillate
[Electronic Circuits]
davekni
November 27, 2022, 06:21:04 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
klugesmith
November 27, 2022, 01:13:28 AM
post Re: Oh Lawd, I got dem Op-Amp blues!
[General Chat]
AkashaStar
November 26, 2022, 06:49:16 PM
post Re: ZVS driver won't oscillate
[Electronic Circuits]
AstRii
November 26, 2022, 04:48:39 PM
post Re: IF D95T vs IF D95OC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
RoamingD
November 26, 2022, 06:56:51 AM
post Re: IF D95T vs IF D95OC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alexhanyuan
November 25, 2022, 11:28:15 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 25, 2022, 12:05:50 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 25, 2022, 07:53:52 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 24, 2022, 08:08:48 AM
post Re: EEFL backlight circuits
[Light, Lasers and Optics]
klugesmith
November 24, 2022, 07:26:49 AM
post Re: Air cored inductors proximity to conductive objects
[General Chat]
davekni
November 24, 2022, 03:02:11 AM
post Re: Solid State “rheostat” that will withstand high electrostatic fields
[General Chat]
AkashaStar
November 24, 2022, 02:25:42 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 24, 2022, 01:45:33 AM
post Re: Air cored inductors proximity to conductive objects
[General Chat]
John123
November 23, 2022, 11:27:18 PM
post Stepper motor drive without switching
[Electronic Circuits]
klugesmith
November 23, 2022, 10:23:07 PM
post Re: Air cored inductors proximity to conductive objects
[General Chat]
Twospoons
November 23, 2022, 09:29:01 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
Alberto
November 23, 2022, 08:45:37 AM
post Re: Air cored inductors proximity to conductive objects
[General Chat]
davekni
November 23, 2022, 04:44:20 AM
post Air cored inductors proximity to conductive objects
[General Chat]
John123
November 23, 2022, 01:10:17 AM
post Re: Post-Soviet Tesla Coil Teardown and Test
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
November 22, 2022, 08:40:19 PM
post Re: Ericsson RBS 6601 RRUS 12 analysis(kind of)
[Electronic Circuits]
Da_Stier
November 22, 2022, 08:22:09 PM
post Re: Ericsson RBS 6601 RRUS 12 analysis(kind of)
[Electronic Circuits]
Kirby4life
November 22, 2022, 08:45:06 AM
post Ericsson RBS 6601 RRUS 12 analysis(kind of)
[Electronic Circuits]
RickNitro
November 22, 2022, 08:36:11 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
davekni
November 22, 2022, 06:42:31 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
Twospoons
November 22, 2022, 06:40:32 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
klugesmith
November 22, 2022, 04:53:40 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
Twospoons
November 22, 2022, 02:17:08 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
klugesmith
November 21, 2022, 11:03:04 PM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
Alberto
November 21, 2022, 09:55:02 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 21, 2022, 03:09:26 PM
post Re: Post-Soviet Tesla Coil Teardown and Test
[Solid State Tesla Coils (SSTC)]
LoOdaK
November 21, 2022, 09:38:22 AM
post Re: Trichel pulses
[Electronic Circuits]
klugesmith
November 20, 2022, 10:05:15 PM
post Trichel pulses
[Electronic Circuits]
haversin
November 20, 2022, 09:48:37 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
klugesmith
November 20, 2022, 07:17:36 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
November 20, 2022, 02:28:22 PM
post Post-Soviet Tesla Coil Teardown and Test
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
November 20, 2022, 02:03:49 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 20, 2022, 10:00:13 AM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
davekni
November 20, 2022, 05:13:12 AM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
davekni
November 20, 2022, 05:08:31 AM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
alan sailer
November 20, 2022, 01:27:00 AM
post Re: Basic Gate driving doubts
[Solid State Tesla Coils (SSTC)]
davekni
November 19, 2022, 10:12:14 PM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
John123
November 19, 2022, 09:57:35 PM
post Re: Basic Gate driving doubts
[Solid State Tesla Coils (SSTC)]
prabhatkumar
November 19, 2022, 09:50:23 PM
post Re: Basic Gate driving doubts
[Solid State Tesla Coils (SSTC)]
davekni
November 19, 2022, 08:26:45 PM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
davekni
November 19, 2022, 06:53:17 PM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
klugesmith
November 19, 2022, 06:05:47 PM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
Alberto
November 19, 2022, 05:34:46 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 19, 2022, 02:30:04 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
AkashaStar
November 19, 2022, 01:56:10 PM
post Re: Buck converter question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
dru
November 19, 2022, 08:03:56 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 19, 2022, 06:38:00 AM
post Basic Gate driving doubts
[Solid State Tesla Coils (SSTC)]
prabhatkumar
November 19, 2022, 05:37:09 AM
post Re: ZVS driver won't oscillate
[Electronic Circuits]
davekni
November 19, 2022, 03:59:56 AM
post Re: Non-laser pointer
[Light, Lasers and Optics]
klugesmith
November 19, 2022, 03:56:32 AM
post Re: Buck converter question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
November 19, 2022, 03:36:20 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
davekni
November 19, 2022, 03:26:48 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
Alberto
November 19, 2022, 12:40:33 AM
post Re: ZVS driver won't oscillate
[Electronic Circuits]
AstRii
November 18, 2022, 09:32:33 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
klugesmith
November 18, 2022, 05:48:00 PM
post Re: Audio Modulated CRT Flyback Transformer Loud Sparks
[Transformer (Ferrite Core)]
John123
November 18, 2022, 03:49:12 PM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
John123
November 18, 2022, 02:56:49 PM
post IF D95T vs IF D95OC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
RoamingD
November 18, 2022, 01:44:38 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 18, 2022, 11:38:44 AM
post Non-laser pointer
[Light, Lasers and Optics]
klugesmith
November 18, 2022, 10:05:29 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
klugesmith
November 18, 2022, 06:54:55 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Twospoons
November 18, 2022, 06:29:23 AM
post Buck converter question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
dru
November 18, 2022, 06:10:52 AM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
davekni
November 18, 2022, 05:53:15 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 18, 2022, 05:21:52 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
davekni
November 18, 2022, 04:00:04 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
alan sailer
November 17, 2022, 10:24:35 PM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
John123
November 17, 2022, 08:30:00 PM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
klugesmith
November 17, 2022, 07:28:16 PM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
John123
November 17, 2022, 03:38:00 PM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
davekni
November 17, 2022, 04:03:51 AM
post Re: what type of diode is better for make high voltage diode?
[Voltage Multipliers]
davekni
November 17, 2022, 03:57:40 AM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
SimplePortal 2.3.6 © 2008-2014, SimplePortal