What is the purpose of this board?

Thread Starter

Stefg023

Joined Feb 11, 2014
21
Trying to figure out what this is. I'm a complete dummy when it comes to electronics.
This is in the back of a picture with fiber optic lights. 3 led's, a slide switch, battery pack, and timer. I've been told this circuit board is used for the timer.
Every wire is connected to it. Can anyone help? I've also found this is in flashlights, etc. Is it used to give the max power to the led lights?
 

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#12

Joined Nov 30, 2010
18,224
The black lump is called, "glob top". It's a cheap way of protecting an integrated circuit.

You say you got it out of a picture with fiber-optic lights? That would seem to make it the controller for the lights.
 

Thread Starter

Stefg023

Joined Feb 11, 2014
21
Well, that would make sense. I'm assuming this isn't something I can go buy (circuit board). Is it something that I would have to create? I'm starting to think this is out of my league
 

#12

Joined Nov 30, 2010
18,224
With no idea what's under the lump, you have to start with, "What do you want the lights to do?" Make it simple and it can be done with a few transistors. Make it complicated and you might end up programming a micro-controller chip.
 

Thread Starter

Stefg023

Joined Feb 11, 2014
21
Well, I'm trying to power 2 different colored led's to fiber optic lights, and then light up a canvas picture. I'm almost there, but the lights don't shine bright enough. Walk outside, and you can't see them at all.
 

#12

Joined Nov 30, 2010
18,224
Is that:
1) 2 colors of LEDs come on and send light into some fiber optic strands.
2) and the fiber optic strands shine on the canvas picture.
3) the lights stay on until you turn them off or they turn off after some amount of time.
and,
4) you want them brighter than they are now. Bright enough to be clearly seen outside on a sunny day.

More questions. Does that circuit board do anything you want to do? Is it broken? Did it do something useful previously? Is it the basis for this project? Does, "almost there" mean you have everything accomplished except better brightness?
 

Thread Starter

Stefg023

Joined Feb 11, 2014
21
What?

Yes, all of those things.
This circuit board is in a picture that I'm trying to imitate. My picture almost looks as good as hers; with the exception that it's not nearly as bright. Also, mine doesn't have a timer.

After I took off the back of the original picture and found this board, I wondered if it had something to do with the lights, or just the timer.

I guess a better question is, how can I create one of these myself?
 

#12

Joined Nov 30, 2010
18,224
You're stretching my imagination for what to do. Do you already have some LEDs that aren't bright enough? If you do, you must have a driver for them, right? What are these LEDs and driver that aren't bright enough? From that, we can find some LEDs that are brighter and a proper driver for them.

Is the power supply a plug-in transformer? What are its voltage and current ratings?
 

Thread Starter

Stefg023

Joined Feb 11, 2014
21
Yes. My power source is batteries. For example, I would use 3 AA's, so 4.5v, to power a white led with 3.3 fv, and 25 current. For that, I'd use a 68 ohm resistor. It looks bright to me, but not when you go outside.
And the picture I'm imitating has 3 different colored led's that shine bright as ever. Don't know what I'm doing wrong.


Also, djsfantasi....I don't understand what's wrong with getting a second opinion? The more input, the better for me.
 

#12

Joined Nov 30, 2010
18,224
A little off with the math.
4.5V - 3.3V = 1.2V
1.2V/68 ohms is 17.6 ma.
Perfect for the, "usual" LED that is limited to 20 ma.

We can look up some heavier quality LEDs but you need to realize that good indoor lighting is about 100 lumens (or candle powers or something like that), but sunlight is 100 THOUSAND lumens. You actually wouldn't want sunlight quality on your picture because nobody could look at it...their eyes would slam shut.

Where are you? W need to find a place to buy better LEDs.
 

mcgyvr

Joined Oct 15, 2009
5,394
You can "overdrive" LEDs but the lifespan will be shorter (but probably plenty long enough).. and it might start to get a bit warm. I'd expect your artwork will be faded from the sun long before the LED dies out.

Just add 1 more 68 ohm resistor in parallel with the other and see if thats sufficiently "bright" for you. (2 x 68 ohm in parallel is equivalent to a 34 ohm resistor)

Or you can find a better LED with a higher rated "lumen" output at the same current level.


Also remember as your batteries start to drain the LED will slowly get "dimmer" too..
 

#12

Joined Nov 30, 2010
18,224
Here's a place that I use, and the page of white LEDs.
They go from ordinary to :eek:
So, estimate...what do you want? Two times as bright? Ten times as bright?

A 20 ma LED is labeled as 5000 milli-lumens.
You're going to want a small viewing angle so they will put the light into a narrow beam for the fibers.

http://www.mouser.com/Search/Refine.aspx?N=14873455

Here are some narrow beam LEDs, 16 times as bright, but expensive.

http://www.mouser.com/Optoelectroni...-Power-LEDs-White/_/N-8usfj?P=1z0wunhZ1z0wtwp

Here is a much better price in an 80 degree wide beam...
If you have a bundle of fibers, they can cover the front of the LED and catch nearly all the light.

http://www.mouser.com/Optoelectroni...ers/High-Power-LEDs-White/_/N-8usfj?P=1z0wuhf
 
Last edited:

Metalmann

Joined Dec 8, 2012
703
"It looks bright to me, but not when you go outside."




Are you sure you want it that bright?

Will this picture naturally be outside, while viewing?
 

#12

Joined Nov 30, 2010
18,224
6500 K is , "How white do they look?"
You're after lumens of "flux". That's, "How bright are they?"
 
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