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# LED SIGN help.

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#### dzyubin

##### New Member
I want to make a led sign, like a strip. such as [ 9--switch---Resistor-led-resistor-led]

But I want at least 50 led.

I got an idea what to do, but it has been years since I used Led's and resistors so please give me a descriptive list what to buy. I need to know the right thing to buy preferably radioshack.

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You just want to light the LEDs like a simple signboard?

What colour (color) LED's, it will determine the size of the resistor.

I got an idea what to do
You'll have to let us know a bit more about it.

sorry for lack of information. I want either 5 or 10mm leds. Multicolored(or green-red it will do) , or It don't matter for now. I want just want a single signboard, after this project of course I will get into more advanced(flashing, motion sensor, and others) because i haven't touched a soldering iron in years.

thak you

Any ideas ?

You will need to decide on a colour because that will determine the resistance for the series resistor

V+ -----> Led x ? -----> Resistor ----> Ground

Led x ? = Number of Led's

How to calculate resistor value:

R = [(V+) - (Led x ?) * (Led Voltage Drop)] / (Desired Current 5-20mA)

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Well since I am planning to use 9v. batteries and I am going to make two LED wall-art signs.

-first one - 50 red LEDS -switch--9v

-second one- 25 blue-30-green -swtich--9v

and I am making a strip of LEDS for a door

-100 blue LEDS-switch---power will depend on the amount.

THANK you

Uh...9V batteries? How many? How long do you need it to last for?

What colour (color) LED's, it will determine the size of the resistor.

Not the size, but the value I guess.

I am hoping it to last couple month for two 9v.

I am planning to use everything from RADIO SHACK so please someone pick the best value and the right stuff thank you.

How Do I caclute what resistor Do i need ? LED? batteries?

Couple of months, wishful thinking. Small 9v batteries are rated in mAh. Try connecting a single LED, 1K resistor and a 9v battery. See how long it lasts.

You'd be lucky to get 2 hours
Are other battery options available to you?

I also got a D_C 12v adapter. Wow 2 hours... Well What about 50 led's for a 12v adapater and about 10 leds for a 9v batteries?
Also available

D batteries and C batteries I don't know if this will help, can buy a good amount so they run for a little longer.

What about 50 LED's with 3 D's batteries?

Thank you

The power adapter is a start
How much power is it rated for?

12V will power about 5 red led's (2v) at 20mA
20mA * 10 strings = 200mA , shouldn't be too much of a problem for your adapter

5 red led's that is not like nothing. I've seen a LED Sign with 3 D's batteries powering over 60 led's.

How long does it last? Does it flash?

5 Leds per string I said, 10 strings. 5 x 10 = 50
If you want 60 make 12 strings.

Hmm I dont know how you guys test but I have had a red Led soldered to a 3v button cell for over 3 weeks now and it is still going strong.
I done it simply to see how long it would go for and havent finished the test yet cause it is still going!!!

Hmm I dont know how you guys test but I have had a red Led soldered to a 3v button cell for over 3 weeks now and it is still going strong.
I done it simply to see how long it would go for and havent finished the test yet cause it is still going!!!

Different battery technologies!

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