Does LED make for a good strobe?

J

Jordan

Guest
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?
 
"Jordan"
Strobe lights are being made using LEDs.
Click to expand...
** Mostly only "party strobes" .


But are they comparable to say Xenon lamps, as used for car ignition
timing lamps.
Click to expand...
** Not if using white LEDs.

The phosphor has quite a long persistence.


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?
Click to expand...

** Sure, use any colour or combination of "super bright" LEDs you like.



.... Phil
 
Jordan schrieb:

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?
Click to expand...
Hello,

I did that, if the flash is short enough you get a good image. If there
is ambient light your strobe should be brighter.

Bye
 
On 14/06/13 19:17, Uwe Hercksen wrote:
Jordan schrieb:

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?

Hello,

I did that, if the flash is short enough you get a good image. If there
is ambient light your strobe should be brighter.

Bye
Click to expand...
Phil & Uwe,

Very good, thank you.
 
Jordan schrieb:


Very good, thank you.
Click to expand...
Hello again,

an example for the needed flash time.
A wheel rotates with 3000 revolutions per minute and it should move not
more than 1 degree during the strobe flash.
There are 50 revolutions per second, one revolution is 20 ms long. 1
degree is 20/360 ms or 55 ľs.
Some 10 microseconds will do.

If the flash is 1/1000 second long, the wheel will rotate 360/20 degrees
within that time, 18 degrees, this is not a sharp image.

Bye
 
On 14/06/13 23:57, Uwe Hercksen wrote:
Jordan schrieb:


Very good, thank you.

Hello again,

an example for the needed flash time.
A wheel rotates with 3000 revolutions per minute and it should move not
more than 1 degree during the strobe flash.
There are 50 revolutions per second, one revolution is 20 ms long. 1
degree is 20/360 ms or 55 ľs.
Some 10 microseconds will do.

If the flash is 1/1000 second long, the wheel will rotate 360/20 degrees
within that time, 18 degrees, this is not a sharp image.

Bye
Click to expand...
Thanks Uwe,

Does your project use a triggered switch that is synchronised with each
turn of the rotor?
Is there available a circuit diagram?
 
"Jordan" <jordan@koora.net> wrote in message
news:kpg6jm$t3i$1@dont-email.me...
On 14/06/13 23:57, Uwe Hercksen wrote:


Jordan schrieb:


Very good, thank you.

Hello again,

an example for the needed flash time.
A wheel rotates with 3000 revolutions per minute and it should move not
more than 1 degree during the strobe flash.
There are 50 revolutions per second, one revolution is 20 ms long. 1
degree is 20/360 ms or 55 ľs.
Some 10 microseconds will do.

If the flash is 1/1000 second long, the wheel will rotate 360/20 degrees
within that time, 18 degrees, this is not a sharp image.

Bye


Thanks Uwe,

Does your project use a triggered switch that is synchronised with each
turn of the rotor?
Is there available a circuit diagram?
Click to expand...
Google works...

http://www.eeweb.com/blog/extreme_circuits/automotive-led-timing-light

http://tehnikservice.net/2011/12/10/automotive-led-timing-strobe/

http://www.howtoalmanac.com/kevin/projects/automotive/timinglight.htm

If you want to get a little fancy with the inductive pick-up (or you're too
lazy or uninspired to make your own), you can get a professionally-made one
through eBay; http://www.ebay.com.au/itm/151048454876

--
Bob Milutinovic
Cognicom
 
On 15/06/13 13:38, Bob Milutinovic wrote:

Is there available a circuit diagram?

Google works...

http://www.eeweb.com/blog/extreme_circuits/automotive-led-timing-light

http://tehnikservice.net/2011/12/10/automotive-led-timing-strobe/

http://www.howtoalmanac.com/kevin/projects/automotive/timinglight.htm
Click to expand...
Interesting, these have no positively timed pulse, very simple thanks.
 
On 14/06/2013 10:11 AM, Jordan wrote:
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?
Click to expand...
**As PA has suggested, white LEDs possess too long a a persistence to be
effective as a serious strobe light, but you can use RGB LEDs to provide
a close approximation to white light. Speed is not a problem for RGB
LEDs. I've used these in a recent project:

http://www.ledsales.com.au/catalog/index.php?main_page=product_info&cPath=148_188_221&products_id=777

They are excellent value for money.



--
Trevor Wilson www.rageaudio.com.au
 
Jordan schrieb:


Does your project use a triggered switch that is synchronised with each
turn of the rotor?
Is there available a circuit diagram?
Click to expand...
Hello,

it was a complex project to measure sedimentation inside a rotating
centrifuge using digital image processing. The strobe was only a
subsystem for lighting the probe glases. I used about 20 RGB LEDs to
select red, green, blue, yellow, magenta, cyan and white light.
A IR reflective sensor was used for triggering. The duration of the LED
pulse was selectable in steps of 10 ľs up to 200 ľs.

The circuit is not useful for an automotive strobe.

Bye
 
"Trevor Wilson" <trevor@SPAMBLOCKrageaudio.com.au> wrote in message
news:b270eeF960uU1@mid.individual.net...
On 14/06/2013 10:11 AM, Jordan wrote:
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?

**As PA has suggested, white LEDs possess too long a a persistence to be
effective as a serious strobe light, but you can use RGB LEDs to provide a
close approximation to white light. Speed is not a problem for RGB LEDs.
I've used these in a recent project:

http://www.ledsales.com.au/catalog/index.php?main_page=product_info&cPath=148_188_221&products_id=777
Click to expand...
For an automotive IGN strobe, you could possibly use a UV security marking
pen to highlight the timing marks and strobe it with a UV LED.

Might work better still with a background of white correction fluid applied
first.
 
On 18/06/13 07:08, Ian Field wrote:
For an automotive IGN strobe, you could possibly use a UV security
marking pen to highlight the timing marks and strobe it with a UV LED.
Click to expand...
Thanks for the info.
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.
 
On 17/06/13 09:35, Trevor Wilson wrote:

**As PA has suggested, white LEDs possess too long a a persistence to be
effective as a serious strobe light, but you can use RGB LEDs to provide
a close approximation to white light. Speed is not a problem for RGB
LEDs. I've used these in a recent project:

http://www.ledsales.com.au/catalog/index.php?main_page=product_info&cPath=148_188_221&products_id=777


They are excellent value for money.
Click to expand...
Point taken about white LED persistence - good info.
Does it happen in the LED, or the human eye?
Those RGB LEDs are probably too big, but they look pretty nifty and I
should buy one just to play with!
 
"Jordan"

**As PA has suggested, white LEDs possess too long a a persistence to be
effective as a serious strobe light, but you can use RGB LEDs to provide
a close approximation to white light. Speed is not a problem for RGB
LEDs. I've used these in a recent project:

http://www.ledsales.com.au/catalog/index.php?main_page=product_info&cPath=148_188_221&products_id=777


Point taken about white LED persistence - good info.
Does it happen in the LED, or the human eye?
Click to expand...
** Do you bother reading posts at all ?

Try reading mine again pal, its number 2 in the thread.



....... Phil
 
On 18/06/2013 9:16 AM, Jordan wrote:
On 17/06/13 09:35, Trevor Wilson wrote:

**As PA has suggested, white LEDs possess too long a a persistence to be
effective as a serious strobe light, but you can use RGB LEDs to provide
a close approximation to white light. Speed is not a problem for RGB
LEDs. I've used these in a recent project:

http://www.ledsales.com.au/catalog/index.php?main_page=product_info&cPath=148_188_221&products_id=777



They are excellent value for money.


Point taken about white LED persistence - good info.
Does it happen in the LED, or the human eye?
Click to expand...
**As PA has already explained, the problem lies with the construction of
all white LEDs. A white LED is actually a blue LED, with a fluorescent
coating. The coating is the problem. It has a persistence.


Those RGB LEDs are probably too big, but they look pretty nifty and I
should buy one just to play with!
Click to expand...
**You could consider a green LED, as they are not only available in in
quite high outputs, but the human eye is highly sensitive to green.


--
Trevor Wilson www.rageaudio.com.au
 
"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.
Click to expand...

** 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.

That is the way to go.



..... Phil
 
On 18/06/2013 12:50 PM, Trevor Wilson wrote:
On 18/06/2013 9:16 AM, Jordan wrote:
On 17/06/13 09:35, Trevor Wilson wrote:

**As PA has suggested, white LEDs possess too long a a persistence to be
effective as a serious strobe light, but you can use RGB LEDs to provide
a close approximation to white light. Speed is not a problem for RGB
LEDs. I've used these in a recent project:

http://www.ledsales.com.au/catalog/index.php?main_page=product_info&cPath=148_188_221&products_id=777




They are excellent value for money.


Point taken about white LED persistence - good info.
Does it happen in the LED, or the human eye?

**As PA has already explained, the problem lies with the construction of
all white LEDs. A white LED is actually a blue LED, with a fluorescent
coating. The coating is the problem. It has a persistence.


Those RGB LEDs are probably too big, but they look pretty nifty and I
should buy one just to play with!

**You could consider a green LED, as they are not only available in in
quite high outputs, but the human eye is highly sensitive to green.


Why not a laser diode module with a diverging lens to give the size of
Click to expand...
spot needed.
 
Jordan schrieb:

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.
Click to expand...
Hello,

if you want to illuminate the spinning part with one 5 mm LED only, you
need:

very low ambient light
the LEDs should be close to the spinning part.
only a small area should be illuminated
a superbright LED should be used
green light would be most efficient for human sight

Bye
 
"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:b2a0dvFsshlU1@mid.individual.net...
"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.
Click to expand...
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.

Winding your own bigger transformer on the basis of the original is
complicated by an extra winding in series with the capacitor charging
circuit that augments the base drive pulses - as the capacitor charges to
maximum; the augment current tails off to conserve the battery. This feature
offers no advantage in a repetitive flash application.

Some disposable cameras have a slide switch for the flash - but increasingly
they have a push button and a few extra transistors for a latch controlling
power to the flash circuit.

Its a matter of preference - but when I needed a 6V powered strobe for
timing small motorcycles, I used a push-pull inverter.
 
"Uwe Hercksen" <hercksen@mew.uni-erlangen.de> wrote in message
news:b2atneF4btlU1@mid.dfncis.de...
Jordan schrieb:

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.

Hello,

if you want to illuminate the spinning part with one 5 mm LED only, you
need:

very low ambient light
the LEDs should be close to the spinning part.
only a small area should be illuminated
a superbright LED should be used
green light would be most efficient for human sight
Click to expand...
You can also get green "dayglo" paint to highlight the target to make it
even more conspicuous.
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top