LED circular board

LED Robin

Hi All
This is my very first post, so please try to help!
I would like to build or have built a circular LED board powered by 240V with 11 LED lights, switched plus one extra also switched but separately but don't have a clue how to go about it. Where do I start looking? Be kind - no wise cracks!
Regards Robin

the beer revolu

Take a trip out to Maplin in Blackpool.
They should have everything you need and will usually offer advice.

LED Robin

the beer revolu wrote: »

Take a trip out to Maplin in Blackpool.
They should have everything you need and will usually offer advice.

Thank you beer.......been there, done that, to no avail.
Regards Robin

Knifey Spoony

You might get a better response in the electronics forum:

http://www.boards.ie/vbulletin/forumdisplay.php?f=1570

It is not very clear from your description what you want. Is it just a board with 12 LED's, 11 of them controlled by one switch, the 12th LED controlled by a separate switch? What is the application you have in mind for the board? Why do you want to run it off 220V? LED's will only work off low voltage DC, ~5V, so the 220V AC from the mains blow normal LED's.

LED Robin

Knifey Spoony
I need a 6" diameter led circuit board with 11 LED thereon which can be powered by standard mains current, reduced to suit the LED's. The 12th LED needs to be completely separate (hanging on some wire?) from the circuit board to back light a small opaque sign.
Thank you
Robin

TheChizler

LED Robin wrote: »

Knifey Spoony
I need a 6" diameter led circuit board with 11 LED thereon which can be powered by standard mains current, reduced to suit the LED's. The 12th LED needs to be completely separate (hanging on some wire?) from the circuit board to back light a small opaque sign.
Thank you
Robin

My advice would be to go to Maplin and buy 12 LEDs of the brightness you need, with a nominal voltage drop less than, say, 5 V (USB phone charger!), and 12 corresponding resistors to to run those LEDs optimally on a 5 V supply, the Maplin guy should help you with this, but it's pretty much find the corresponding current (Id) for the nominal voltage drop (Vd)you need from the data sheet for the LEDs, feed it into this formula (R = (Vcc - Vd)/Id) where R is the resistance you need and Vcc the supply voltage, and find the closest available resistor. Also buy a female USB connector for whatever old USB cable you have lying around. Also get wire (different colours if possible) and a soldering iron and solder if you don't have any. And of course two switches.

Get a thin sheet of wood/chipboard/plastic and the smallest drill bit you can find and drill holes for the legs of the LEDs (or a larger bit so you can fit the LED 'bulb' into the hole). Fit the LEDs into the holes and connect their cathodes (shorter legs) together with wire and solder. Solder the appropriate resistor to each anode. Solder the other end of 11 resistors to one end of one switch and the lone one to the other, and solder the other end of the switches to the positive terminal of the USB connector, and the negative terminal to the cathodes of the LEDs. Use plenty of tape to make sure that no exposed metal can touch anything else and that everything's secure. Even better if you incorporate these parts into the mounting material to secure them. Find an appropriate USB charger (current capacity greater than the sum of the currents through all the LEDs), which should probably be done at the start of the process.

The reason I say use 12 resistors instead of 1 small one is that if you make a mistake in wiring or a few blow it won't take the rest with them.

You might be advised to incorporate a fuse right after the USB connector to ensure any problems don't destroy your charger. Size it to the next size up after the current consumption of the circuit. In fact test it out with three AA cells first to make sure it's wired correctly if you don't have a multimeter.

LED Robin

Dear 'TheChizler'
Brilliant - I will try that and thank you so much. now lets see if Maplin can make sense of what you have suggested!
A grateful Robin

SteelyDanJalapeno

How much were you thinking of spending? or what's your budget?

Is this something you want to do yourself or would you prefer to pay someone to do it for you?

ted1

you need to be clearer.


Is it for college project or something?
why do you need 12 LED's, do you just need light? There's loads of different LEDs out there.

if its just to back light a sign, a GU10 LED might be the easiest way, just need a GU10 holder and a bit of cable with a plug on it.

mawk

Hi led robin,

I recently wrote up a guide with some pictures in a thread in the engineering section.

If you think you can't manage yourself (you probably can it's easy) let me know and send on a sketch and I'll make you one for the price of a few pints