LED SIGN help.

[dzyubin]

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.

Thank you in advance. --John

 

[blueroomelectronics]

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

 

[birdman0_o]

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

 

[House0Fwax]

I got an idea what to do

You'll have to let us know a bit more about it.

 

[dzyubin]

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.

 

[dzyubin]

thak you

Any ideas ?

 

[birdman0_o]

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)

 

[dzyubin]

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

 

[birdman0_o]

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

 

[Boncuk]

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

Not the size, but the value I guess.

 

[dzyubin]

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?

 

[blueroomelectronics]

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.

 

[birdman0_o]

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

 

[dzyubin]

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

 

[birdman0_o]

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

 

[dzyubin]

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.

 

[blueroomelectronics]

How long does it last? Does it flash?

 

[birdman0_o]

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

 

[zorbzz]

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!!!

 

[birdman0_o]

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!