Hi,
I'm Daniele Kaehr, and I'm a photographer and a new member of the forum.
I've have few question:
I would like to build a led wrist bracelet for a photographic project i'm working on.
1) Is it possible to power the leds with a battery instead of a source connected to the power grid and get enough light out if it?
2) The bracelet must be safe to wear on the skin, any special attention?
3) I need the bracelet to be emit as much light as possible, what should i use?
any hits or tips are appreciated.
thx in advance for your answers. greets Daniele Kaehr
Led wrist bracelet
Moderator: T.Hoffmann
Hi Daniele, welcome to our forum.
1) Sure. If you use enough batteries to get the output voltage you need, it's no problem.
2) not really, as you operate with low voltage there is no danger. the only thing could be heat of highpower LEDs, but if you use normal 5mm/3mm or superflux there is definitely no danger you have to pay attention to
3) this is a bit of a imprecise information. As much light as possible can be so much, that you can't even look into the leds (but then you would need a rucksack for the batteries
)
So what do you really need: focused spotlight or homogeneous light in all directions? Could you make an example/comparison of how bright the wrist bracelet should get?
Greets
Fightclub
1) Sure. If you use enough batteries to get the output voltage you need, it's no problem.
2) not really, as you operate with low voltage there is no danger. the only thing could be heat of highpower LEDs, but if you use normal 5mm/3mm or superflux there is definitely no danger you have to pay attention to
3) this is a bit of a imprecise information. As much light as possible can be so much, that you can't even look into the leds (but then you would need a rucksack for the batteries
)So what do you really need: focused spotlight or homogeneous light in all directions? Could you make an example/comparison of how bright the wrist bracelet should get?
Greets
Fightclub
Hi, thx for your reply.
I was looking at the flexible LED strips. They seems to work great for me. They are already mounted on a flexible strip.
So basically I take a strip. I cut it to fit the wrist and I plug in a max of 12V, using a series of 1.5V batteries.
What is "Recom. forward current of 180mA"? should I check if the batteries feed more current into the system?
Or is it better if i put together myself a bunch of 5mm LED?
Photography needs light. The concept is that someone will move/dance for a while (5-10sec) on a late evening landscape in front of a camera set with the shutter wide open for a long exposure.
The led must emit enough light to produce a trace on film even with fast movement. Fast movement means that the led stays in a specific position for a small amount of time. In this amount of time the leds must expose the film leaving a trace that represent the movement.
I hope this is clear enough.
thx, Daniele Kaehr
I was looking at the flexible LED strips. They seems to work great for me. They are already mounted on a flexible strip.
So basically I take a strip. I cut it to fit the wrist and I plug in a max of 12V, using a series of 1.5V batteries.
What is "Recom. forward current of 180mA"? should I check if the batteries feed more current into the system?
Or is it better if i put together myself a bunch of 5mm LED?
Photography needs light. The concept is that someone will move/dance for a while (5-10sec) on a late evening landscape in front of a camera set with the shutter wide open for a long exposure.
The led must emit enough light to produce a trace on film even with fast movement. Fast movement means that the led stays in a specific position for a small amount of time. In this amount of time the leds must expose the film leaving a trace that represent the movement.
I hope this is clear enough.
thx, Daniele Kaehr
-
Sailor
- Moderator
- Beiträge: 9427
- Registriert: Di, 28.11.06, 22:16
- Wohnort: Saarland, Deutschland und die Welt
"Recom. forward current of 180mA" means the typical current of 180 mA in 12V-systems for a full stripe. The 12V-source has to have a higher capacity in current, even the batteries. With batteries is no need to check the current (if the voltage is 12 Volt). The current-control is build-in.
LED-light will produce spots on a photo. A lot of LED´s close together and moving the LED´s will minimize spots.
LED-light will produce spots on a photo. A lot of LED´s close together and moving the LED´s will minimize spots.
Probably yes. You don't need a lot of batteries just to get the required 12V (and if this should be used during dancing, your dancer will highly appreciate each oz of lower weightOr is it better if i put together myself a bunch of 5mm LED?
). In order to get homogeneous light, you should also grind the LEDs to achieve a better light dispersion.-
Ragnar Roeck
- Ultra-User
- Beiträge: 924
- Registriert: Di, 20.02.07, 19:40
When the LEDs will be driven by a battery they'll not give any spots, but a constant lighttrail on the picture, just as asked for. The spots mentioned here come from a pulsating power source (I will not go into details here) like it's used for bicycle rear-lights and the latest break-lights on cars. Eyes are to "slow" to notice this usually, unlike the "eye" of a camera. To put it simple: if you use batteries you are safe.Sailor hat geschrieben:"Recom. forward current of 180mA" means the typical current of 180 mA in 12V-systems for a full stripe. The 12V-source has to have a higher capacity in current, even the batteries. With batteries is no need to check the current (if the voltage is 12 Volt). The current-control is build-in.
LED-light will produce spots on a photo. A lot of LED´s close together and moving the LED´s will minimize spots.
Hi,
thanks for all your answers.
I've another question.
8x 1.5V batteries AA is enough to get a good light out of, let's say 10 led on a http://www.leds.de/p435/LED_strips_modu ... m_12V.html
Should I put some other batteries in parallel to have more current?
thx dani
thanks for all your answers.
I've another question.
8x 1.5V batteries AA is enough to get a good light out of, let's say 10 led on a http://www.leds.de/p435/LED_strips_modu ... m_12V.html
Should I put some other batteries in parallel to have more current?
thx dani