LED string

[bassplaya12]

Hey guys,

I had a question about a project I was thinking about.  This one actually isn't for a stompbox per say but it's not really much different.  I'm building an LED light for my aquarium and you guys know the most about electronics haha, so naturally I'm here asking.  My general idea is to string like 5 or so LED's (two blue, two uv, one white) in a row with the proper limiting resistors.  It needs a switch and im just gonna run it off of some sort of power adapter that I prob having lying around my music room.  Then throw it in a box and call it good.  I guess where I need help is the actual wiring hah. Could I do this on a vero board?  What kind of power would I need?

[Philippe]

My general idea is to string like 5 or so LED's (two blue, two uv, one white) in a row with the proper limiting resistors.  It needs a switch and im just gonna run it off of some sort of power adapter that I prob having lying around my music room.  Then throw it in a box and call it good. 

Are you going to submerge the box of LEDs into the acquarium itself? Probably not a good idea to hook it up to an AC adapter & turn it on/off using the underwater switch...something about electrocution (although I could be mistaken). Sticking with a 9V DC battery might provide the safer route.

You'll probably want to consider one of those watertight enclosures & gasket/seal the areas that are drilled for the LEDs & switch. A SPDT or DPDT should suffice since the switch is only being used to turn the 'juice' on for the LEDs. Choice of resistors (anywhere from 2-10K) will serve to control the brightness of the LEDs + conserve battery life (unless you are still planning to use that AC power supply). Wiring would be similar to doing a simple A/B box (minus the jacks).

A set of flashing underwater ultrabright LEDs inside an acquarium sounds kind of cool...might even make for a semi-profitable & marketable DIY item for tropical fish stores and/or head shops.

[G. Hoffman]

Enter all the data into THIS WIZARD, and it will spit out the circuit for you.  If your different colors have different forward voltages, average them, and use the lowest forward current.  Add the switch anywhere.

Running at least some of them in series makes the system more efficient, since you are using the LEDs to get most of your voltage drop, use much smaller resistors, and waste less of your power as heat.  Use less resources, and save money at the same time (granted, only a few cents, but still.)  I'm making a UV array right now for exposing circuit boards, with 40 strings of 5 LEDs and a 27 ohm resistor (yes, that's 200 LEDs).  Unfortunately, I decided to wire this thing up, ah, point to point, I guess, so its going to take a while to wire it up!  I spent about 4 hours tonight, and wired up 25 LEDs.     I've got to find a way to speed this up.


Gabriel

[PRR]

He won't have wet LEDs for long. Electrolysis will eat the leads off in a day.

Some fish may die sooner.

Assuming air-mount....

I don't see a need for a board. Twist LED leads to each other, solder, hot-glue to a popsicle stick. OK, vero may be neater.

[bassplaya12]

It's gonna be mounted in the air pointed towards the water, but still near water. ^^You said just twist them together?  Also how and where would I wire the power and switch?

[bassplaya12]

Enter all the data into THIS WIZARD, and it will spit out the circuit for you.  If your different colors have different forward voltages, average them, and use the lowest forward current.  Add the switch anywhere.

Running at least some of them in series makes the system more efficient, since you are using the LEDs to get most of your voltage drop, use much smaller resistors, and waste less of your power as heat.  Use less resources, and save money at the same time (granted, only a few cents, but still.)  I'm making a UV array right now for exposing circuit boards, with 40 strings of 5 LEDs and a 27 ohm resistor (yes, that's 200 LEDs).  Unfortunately, I decided to wire this thing up, ah, point to point, I guess, so its going to take a while to wire it up!  I spent about 4 hours tonight, and wired up 25 LEDs.     I've got to find a way to speed this up.


Gabriel

I'm not sure what my voltage and current will be yet

[G. Hoffman]

Enter all the data into THIS WIZARD, and it will spit out the circuit for you.  If your different colors have different forward voltages, average them, and use the lowest forward current.  Add the switch anywhere.

Running at least some of them in series makes the system more efficient, since you are using the LEDs to get most of your voltage drop, use much smaller resistors, and waste less of your power as heat.  Use less resources, and save money at the same time (granted, only a few cents, but still.)  I'm making a UV array right now for exposing circuit boards, with 40 strings of 5 LEDs and a 27 ohm resistor (yes, that's 200 LEDs).  Unfortunately, I decided to wire this thing up, ah, point to point, I guess, so its going to take a while to wire it up!  I spent about 4 hours tonight, and wired up 25 LEDs.     I've got to find a way to speed this up.


Gabriel

I'm not sure what my voltage and current will be yet

That's what data sheets are for. 

Typically, LEDs seem not to like more than about 20mA.  Forward voltage will be listed on the data sheet, and is usually different for different colors.


You remember what I said up there about soldering up 200 UV LEDs for a PCB exposure rig.  Well, I've done 180 so far.  My neck is cricked, my back is aching, and my eyes are pretty much totally crossed.  Each joint has some variation on a Western Union Splice.  REALLY dumb idea on my part, but hey, I've only got 20 more to go, and I can practically do the splice blindfolded at this point, so I guess we can call it a learning experience, right?  It's only taken me about 12 hours so far!   


Gabriel

[linny1982]

how big is the tank? 5 leds might not be enough. although they can look really bright when you look right at them they don't focus the light very well so alot can be wasted. even for a small tank i'd be thinking upward of 30 leds.

[bassplaya12]

how big is the tank? 5 leds might not be enough. although they can look really bright when you look right at them they don't focus the light very well so alot can be wasted. even for a small tank i'd be thinking upward of 30 leds.

It's for at night time.  30 would be utterly ridiculous.  Just trying to create a soft glow not land airplanes through my window

[JKowalski]

Just trying to create a soft glow not land airplanes through my window

[linny1982]

[/quote]

It's for at night time.  30 would be utterly ridiculous.  Just trying to create a soft glow not land airplanes through my window
[/quote]

oh ok. you said fish tank light and i thought replicating a normal light my bad

[mantella]

I've been wanting to make an LED light table for tracing and I'm wondering about using these:
http://www.besthongkong.com/product_info.php?products_id=249

If they already have resistors attached, would I just wire them all up in parallel (using a 12VDC power supply)?

[JKowalski]

I've been wanting to make an LED light table for tracing and I'm wondering about using these:
http://www.besthongkong.com/product_info.php?products_id=249

If they already have resistors attached, would I just wire them all up in parallel (using a 12VDC power supply)?

Yes.