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L.E.D. Power supply question HELP!!!

A

Abad

Jan 1, 1970
0
I wish to make a ring of LED's to put around a camera lens. What woul
dbe the best way to figure out how much power and how to power this
ring? Would there be a way to put a dimmer on there as well?

Any help greatly appreciated!

Abad
 
R

Robbie Banks

Jan 1, 1970
0
This all depends on what power source you have available and the colour of
LED's you wish to use.

For example with a 12v supply, you can put 5 red LED's in a series with a 47
Ohm resistor, thus you could prbably make the ring with 15 or 20 LED's and
therefore 4 strings. IF you wish a different colour you have to look at the
forward voltage and work out how many you can put in series together with
your power source. With 5V you will be limited to either 1 or 2

I'd personally run it from a transformed power supply to 12v DC and design
the strings accordingly.
You probably want to use an astable vibrator of some sort using a 555 timer
to run the LED's. You can dim this by varying the duty cycle of the
vibrator. Or, you can place a variable resistor in series with the LED
strings and change this to dim the LED's

Hope this helps. But, as they say there are many ways to skin a cat so I'm
sure there will be other solutions you prefer

Robbie
 
J

Jacobe Hazzard

Jan 1, 1970
0
Abad said:
I wish to make a ring of LED's to put around a camera
lens. What woul dbe the best way to figure out how much
power and how to power this ring? Would there be a way to
put a dimmer on there as well?

Any help greatly appreciated!

Abad

Is this for macro photography?
Have you looked at the Nikon adapter that does this? It might give you some
idea how to proceed, and also I doubt you could build one for less than what
they cost from a camera shop, unless you are looking for coloured light or
something odd like that.
 
W

Watson A.Name \Watt Sun - the Dark Remover\

Jan 1, 1970
0
Abad said:
I wish to make a ring of LED's to put around a camera lens. What woul
dbe the best way to figure out how much power and how to power this
ring? Would there be a way to put a dimmer on there as well?

Any help greatly appreciated!

See URL http://www.photoprojects.net/index8.html


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###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
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W

Watson A.Name \Watt Sun - the Dark Remover\

Jan 1, 1970
0
Robbie said:
This all depends on what power source you have available and the colour of
LED's you wish to use.

For example with a 12v supply, you can put 5 red LED's in a series with a 47
Ohm resistor, thus you could prbably make the ring with 15 or 20 LED's and
therefore 4 strings. IF you wish a different colour you have to look at the
forward voltage and work out how many you can put in series together with
your power source. With 5V you will be limited to either 1 or 2

I'd personally run it from a transformed power supply to 12v DC and design
the strings accordingly.
You probably want to use an astable vibrator of some sort using a 555 timer
to run the LED's. You can dim this by varying the duty cycle of the
vibrator. Or, you can place a variable resistor in series with the LED
strings and change this to dim the LED's

Really bad advice. Pulsing the LEDs while the shutter is open will
result in an exposure that's incorrect.

Obviously he won't need red LEDs for a camera.
Hope this helps. But, as they say there are many ways to skin a cat so I'm
sure there will be other solutions you prefer

Robbie


--
@@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@,@@[email protected]@[email protected],@@[email protected]@[email protected]@[email protected]@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@@
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f
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D

David Wood

Jan 1, 1970
0
Check out National Semiconductor's dedicated circuits for powering
white illumination LEDs. They offer lot's of control and versatility.
 
L

Louis Bybee

Jan 1, 1970
0
Works now. Didn't work when I tried it earler.

Possibly it was busy?

Thank you.

Louis--
*********************************************
Remove the two fish in address to respond
 
W

Watson A.Name - Watt Sun, Dark Remover

Jan 1, 1970
0
Works now. Didn't work when I tried it earler.

Possibly it was busy?

Thank you.

Let's move on from whether or not the link works to comments on the
contents of the link.



--
@@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@,@@[email protected]@[email protected],@@[email protected]@[email protected]@[email protected]@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@@
 
R

Robbie Banks

Jan 1, 1970
0
Really bad advice. Pulsing the LEDs while the shutter is open will
result in an exposure that's incorrect.

Obviously he won't need red LEDs for a camera.

Not apparent from post if it's a still's camera/video/cctv. Or the app of
the camera. Lighting, SFX. So all input is valid.

Cheers
Robbie
 
D

Dr Engelbert Buxbaum

Jan 1, 1970
0
Watson said:
Obviously he won't need red LEDs for a camera.

I don't know about that. White LED's send out a mixture of blue (from
the chip) and yellow (from a fluorescent dye in the plastic) light. So
adding some green, orange and red LEDs may be necessary to get correct
representation of colours.

Has anybody ever tried to make a truly white light by mixing different
LEDs like that?

In the catalogues I found LEDs with the following wavelengths: 400, 420,
440, 470, 490, 503, 520, 565, 590, 605, 615, 625, 632, 660 nm. Beyond
470 nm those would be superbright LEDs. So apart from a gap around 540
nm (which is unfortunately where the human eye is most sensitive) the
entire visible spectrum is covered. Interesting would be the range
between 450-650 nm, which is about the range of the human eye.
 
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