Wednesday, April 20, 2005
Macro Light Ring Project
Just to inform the masses:
When taking close up pictures, lighting is a problem, because your camera will block a lot of the light shining on the object you are so interested in. The flash is useless because it is usually blocked by the lens barrel, is too bright, lights up one side only, or a combination of all the above. By making a ring of bright LEDs, all of the above problems are solved. This is not an original idea, Canon and Sony make them for unreasonable prices. Many others have built their own homebrewed designs, and this is yet another.
The Design:
Using 100,000mcd typ. white LEDs and a Lithium-ion battery (with built-in over current and under voltage cut-off) from a cell phone, I wish to design a light ring that could illuminate both near(2") and far(12") objects while taking macro shots. I built the ring to mount snug on the barrel of my Sony DSC-S75, and house 16 LEDs, 8 facing forward, and 8 tilted in about 20deg (2" focus from the lens). This ring is overkill for the homebrewer as you could just as easily mount the LEDs on a PCB and tilt them inwards, and this would be much cheaper than a precision fabrication. Either way, I only use 8 at a time, switching between the two set of LEDs with a two on-position switch. The 8 LEDs are in series and pull 3.3V while the battery's voltage varies from 4.2V to 3.0V. I will attempt to build in a circuit that uses a 3.3 voltage regulator, with built in current limit (in addition to an under voltage cut-off), so that I may do away with the resistors.
When taking close up pictures, lighting is a problem, because your camera will block a lot of the light shining on the object you are so interested in. The flash is useless because it is usually blocked by the lens barrel, is too bright, lights up one side only, or a combination of all the above. By making a ring of bright LEDs, all of the above problems are solved. This is not an original idea, Canon and Sony make them for unreasonable prices. Many others have built their own homebrewed designs, and this is yet another.
The Design:
Using 100,000mcd typ. white LEDs and a Lithium-ion battery (with built-in over current and under voltage cut-off) from a cell phone, I wish to design a light ring that could illuminate both near(2") and far(12") objects while taking macro shots. I built the ring to mount snug on the barrel of my Sony DSC-S75, and house 16 LEDs, 8 facing forward, and 8 tilted in about 20deg (2" focus from the lens). This ring is overkill for the homebrewer as you could just as easily mount the LEDs on a PCB and tilt them inwards, and this would be much cheaper than a precision fabrication. Either way, I only use 8 at a time, switching between the two set of LEDs with a two on-position switch. The 8 LEDs are in series and pull 3.3V while the battery's voltage varies from 4.2V to 3.0V. I will attempt to build in a circuit that uses a 3.3 voltage regulator, with built in current limit (in addition to an under voltage cut-off), so that I may do away with the resistors.
# posted by plauale @ 6:11 PM 
