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"Phil Allison"
"Jordan"
The strobe I want isn't for auto ignition timing, but to illuminate a
"stopped" image of a spinning part, which does happen to be in an engine
(with a glass window to see through).
Colour isn't important as long as it's visible. It needs to be as
compact as possible and heatsink type LEDs probably won't be easy for
this, so I'll use the brightest probably 5mm diameter LED I can find.
For the brief duty cycle, maybe I can get away with much higher current
to get higher brightness.
** You are dreaming if you think ONE ordinary LED will do it.
Human eyes do NOT respond well to light pulses less than 1 millisecond
long so the ambient must be near darkness to have any chance.
Really, a Zenon tube is a far better bet - they are very efficient and
can produce huge amounts of light.
A compact, battery operated one is not hard to make - throw away cameras
have the basis of what you need inside.
The disposable camera option has one or two gotchas - the most common type
is powered by a single AA cell and designed for single shot with a
significant recharge time, it might be tricky getting enough power through
the transformer for repetitive flash.
**Indeed. Flash tubes in typical cameras are rated for around 1 ~ 2"Ian Field"
"Phil Allison"
"Jordan"
The strobe I want isn't for auto ignition timing, but to illuminate a
"stopped" image of a spinning part, which does happen to be in an engine
(with a glass window to see through).
Colour isn't important as long as it's visible. It needs to be as
compact as possible and heatsink type LEDs probably won't be easy for
this, so I'll use the brightest probably 5mm diameter LED I can find.
For the brief duty cycle, maybe I can get away with much higher current
to get higher brightness.
** You are dreaming if you think ONE ordinary LED will do it.
Human eyes do NOT respond well to light pulses less than 1 millisecond
long so the ambient must be near darkness to have any chance.
Really, a Zenon tube is a far better bet - they are very efficient and
can produce huge amounts of light.
A compact, battery operated one is not hard to make - throw away cameras
have the basis of what you need inside.
The disposable camera option has one or two gotchas - the most common type
is powered by a single AA cell and designed for single shot with a
significant recharge time, it might be tricky getting enough power through
the transformer for repetitive flash.
** Huh ?
Start by making the discharge cap about 100 times smaller - ie about 1uF.
That's interesting, I didn't know these existed. Cheap too.Why not a laser diode module with a diverging lens to give the size of
spot needed.
On 18/06/13 21:12, keithr wrote:
Why not a laser diode module with a diverging lens to give the size of
spot needed.
That's interesting, I didn't know these existed. Cheap too.
"Jordan"
Does it happen in the LED, or the human eye?
** Do you bother reading posts at all ?
Try reading mine again pal, its number 2 in the thread.
...... Phil
Yes, silly me.
mainframe laser printers. Powering the tubes was a ferking big bank ofOn 19/06/2013 9:03 AM, Phil Allison wrote:
"Ian Field"
"Phil Allison"
"Jordan"
The strobe I want isn't for auto ignition timing, but to illuminate a
"stopped" image of a spinning part, which does happen to be in an
engine
(with a glass window to see through).
Colour isn't important as long as it's visible. It needs to be as
compact as possible and heatsink type LEDs probably won't be easy for
this, so I'll use the brightest probably 5mm diameter LED I can find.
For the brief duty cycle, maybe I can get away with much higher
current
to get higher brightness.
** You are dreaming if you think ONE ordinary LED will do it.
Human eyes do NOT respond well to light pulses less than 1 millisecond
long so the ambient must be near darkness to have any chance.
Really, a Zenon tube is a far better bet - they are very efficient
and
can produce huge amounts of light.
A compact, battery operated one is not hard to make - throw away
cameras
have the basis of what you need inside.
The disposable camera option has one or two gotchas - the most common
type
is powered by a single AA cell and designed for single shot with a
significant recharge time, it might be tricky getting enough power
through
the transformer for repetitive flash.
** Huh ?
Start by making the discharge cap about 100 times smaller - ie about
1uF.
**Indeed. Flash tubes in typical cameras are rated for around 1 ~ 2
Watts of average power. This assumes a cycle time in the order of
several seconds. Discharging (say) 100uF or more @ 300 Volts at a rate
of (say) 50 ~ 100 times per second will destroy almost any flash tube
rapidly.
Funny this thread appeared this week. A couple of weeks back an old
girlfriend asked me about the strobe light I built when I was in school.
She wanted it for her daughter's art display. I dug it out and gingerly
switched it on. The damned thing actually still worked! The tube flashed
erratically, as it certaintly showed significant signs of many hours of
use (at parties and nightclubs). It is a 5 Watt tube, which I managed to
overdrive (at times) to around 10 Watts. Very forgiving things. Still,
they do have limits and it is wise to remain within those limits for
reliable operation. We decided to use an LED.
A high power RGB LED makes a lot more sense. Cheap and dead easy to use.
Fujitsu used to use a bank of flash tubes as the fuser for their
Bare laser diodes aren't all that hard to find, one of the chips in a DVDOn 19/06/2013 12:05 PM, Jordan wrote:
On 18/06/13 21:12, keithr wrote:
Why not a laser diode module with a diverging lens to give the size of
spot needed.
That's interesting, I didn't know these existed. Cheap too.
Some LD modules don't like to be turned on & off quickly - perhaps due to
the integrated driver circuitry.
This project uses a white LED as a strobe, published in August & September 2008.Strobe lights are being made using LEDs.
But are they comparable to say Xenon lamps, as used for car ignition timing lamps. These are very effective at "stopping dead" the
perceived image of a spinning part.
I'd like to make a compact, low power strobe, that won't give a blurred image. Any chance with LEDs?
**You may be correct. Specs on Luxeon emitters seem to bear out the rise"Jordan" <jordan@koora.net> wrote in message news:kpdmqc$k9u$1@dont-email.me...
Strobe lights are being made using LEDs.
But are they comparable to say Xenon lamps, as used for car ignition timing lamps. These are very effective at "stopping dead" the
perceived image of a spinning part.
I'd like to make a compact, low power strobe, that won't give a blurred image. Any chance with LEDs?
This project uses a white LED as a strobe, published in August & September 2008.
http://archive.siliconchip.com.au/cms/A_110798/article.html
SC did some testing of the 1W white Luxeon and a Cree XR-C .
The 10% to 90% full brightness measurement was 290nS, 90% to 10% was 360nS.
To get enough light though, they made the minimum strobe flash period 32uS.
BTW
Some people confuse the slow phosphor used in CRO tubes with white LEDs.
The phosphor used in most white LEDs does not phosphoresce but emits
light by scintillation, an effect that has virtually no light persistence, so the speed
is mostly determined by the underlying blue LED.
**Certainly, but a 5 Watt LED would deliver plenty of light for anythingXenon are much brighter and faster and would be better in bright ambient light.
Here is the info from SCOn 20/06/2013 11:43 PM, yaputya wrote:
"Jordan" <jordan@koora.net> wrote in message news:kpdmqc$k9u$1@dont-email.me...
Strobe lights are being made using LEDs.
But are they comparable to say Xenon lamps, as used for car ignition timing lamps. These are very effective at "stopping dead"
the
perceived image of a spinning part.
I'd like to make a compact, low power strobe, that won't give a blurred image. Any chance with LEDs?
This project uses a white LED as a strobe, published in August & September 2008.
http://archive.siliconchip.com.au/cms/A_110798/article.html
SC did some testing of the 1W white Luxeon and a Cree XR-C .
The 10% to 90% full brightness measurement was 290nS, 90% to 10% was 360nS.
To get enough light though, they made the minimum strobe flash period 32uS.
BTW
Some people confuse the slow phosphor used in CRO tubes with white LEDs.
The phosphor used in most white LEDs does not phosphoresce but emits
light by scintillation, an effect that has virtually no light persistence, so the speed
is mostly determined by the underlying blue LED.
**You may be correct. Specs on Luxeon emitters seem to bear out the rise and fall times will be fast enough for most purposes.
You still have to stretch the LED pulse out to get much light whereas theXenon are much brighter and faster and would be better in bright ambient light.
**Certainly, but a 5 Watt LED would deliver plenty of light for anything but for use in direct sunlight. IOW: In a car engine bay,
a white LED will easily be adequate.
--
Trevor Wilson www.rageaudio.com.au
** Seems this info is wrong - like many others I had read comments about** Not if using white LEDs.
The phosphor has quite a long persistence.