Need help with creating an on/of LED for prop

[Sulla]

I want to put a single whit LED behind a diffused light panel button. I have a simple push for on/push for off switch I want to use. What do I need to make this work? I am thinking of parts from Radio Shack or some other easy place to get the stuff. Wire gauge, LED size, transistors [ yes/no - which one(s) ]. Everything. The switch and LED will be about two inches apart if that helps. I was also planning to rig up a piece of styrene with a hole and side shades to mount the LED in using 2 part epoxy and soldering the wires to the leads on the bottom of the LED sticking through the hole.

Can someone help me?

 

[Sulla]

Oh, and batteries too... I need to know what's appropriate for a single LED like this. I have plenty of room for mounting batteries, transistors, LED, and switch.

 

[NakedMoleRat]

<div class='quotetop'>QUOTE(Sulla @ Jan 24 2007, 03:48 PM) [snapback]1403909[/snapback]</div>

Oh, and batteries too... I need to know what's appropriate for a single LED like this. I have plenty of room for mounting batteries, transistors, LED, and switch.
[/b]

Any blinkie, or just straight on and off?

 

[Harry Harris]

I think this link might help you:

LED calculator

Harry

 

[ATL Kenobi]

Andy,

A quick check of Radio Shack's site shows they have a part number 276-320 White LED. It's rated at 3.6 volts DC, at 20mA. You won't need a transistor. If you want to use typical 1.5 volt battery cells, like AA,C or D, you'll need at least 3 in series to give you 4.5 volts (greater than the 3.6V of the diode). Personally I'd opt for 4 batteries for 6 volts. You'll need a series resistor (6-3.6)/.02 = 120 ohms. This is actually a standard resistor value (brown, red, brown, gold). Just hook the switch, the resistor, the battery, and the LED all in series and it should work just fine.

ATL


<div class='quotetop'>QUOTE(Sulla @ Jan 24 2007, 10:48 AM) [snapback]1403909[/snapback]</div>

Oh, and batteries too... I need to know what's appropriate for a single LED like this. I have plenty of room for mounting batteries, transistors, LED, and switch.
[/b]

 

[Sulla]

<div class='quotetop'>QUOTE(ATL Kenobi @ Jan 24 2007, 11:03 AM) [snapback]1403931[/snapback]</div>

Andy,

A quick check of Radio Shack's site shows they have a part number 276-320 White LED. It's rated at 3.6 volts DC, at 20mA. You won't need a transistor. If you want to use typical 1.5 volt battery cells, like AA,C or D, you'll need at least 3 in series to give you 4.5 volts (greater than the 3.6V of the diode). Personally I'd opt for 4 batteries for 6 volts. You'll need a series resistor (6-3.6)/.02 = 120 ohms. This is actually a standard resistor value (brown, red, brown, gold). Just hook the switch, the resistor, the battery, and the LED all in series and it should work just fine.

ATL
[/b]

Excellent, lots of thanks. I'll work that all out on paper at lunch time here at work :$

And yes, It is just a 'flip the switch and the light burns without blinking, flip the switch again, and it turns off.'

Now that I think about it the switches I have ar not push button. Any suggestions for that?

 

[NakedMoleRat]

Here is a (very) crude drawing I did up in paint. It pretty well explains the set up though. For the switch get a momentary bypass swith (click on, click off). Radioshack, only a couple of bucks.

 

[Gordon Gekko]

Andy,

Not sure if this helps, but I found these at wal-mart in the magazine section. They have a nice, bright 5mm led, switch, and batteries all ready to go. The battery comparment is easy to modify to fit small spaces and you can't beat the price. :thumbsup

I'm currently using one on a Hal 9000.

 

[Sulla]

<div class='quotetop'>QUOTE(Jmtwo @ Jan 24 2007, 11:19 AM) [snapback]1403941[/snapback]</div>

Andy,

Not sure if this helps, but I found these at wal-mart in the magazine section. They have a nice, bright 5mm led, switch, and batteries all ready to go. The battery comparment is easy to modify to fit small spaces and you can't beat the price. :thumbsup

I'm currently using one on a Hal 9000.
[/b]

neat. is the switch a push button? I ne to mount a "retro switch" on top of it. Again, I have plenty of room to do it, so depth is not too much of an issue.

OK, so what I need is the 276-320 White LED 3.6 volts DC at 20mA, 4 AA's with battery holder, and a series resistor that is 120 ohms (A standard, various colors?) wired in series (like NakedMoleRat's very helpful drawing.) And I should be fine?

How's this for the resistor? It's the closest I could find on the shack website to 120 ohm
http://www.radioshack.com/product/index.js...rentPage=search

 

[Jedirick]

<div class='quotetop'>QUOTE(Jmtwo @ Jan 24 2007, 11:19 AM) [snapback]1403941[/snapback]</div>

Andy,

Not sure if this helps, but I found these at wal-mart in the magazine section. They have a nice, bright 5mm led, switch, and batteries all ready to go. The battery comparment is easy to modify to fit small spaces and you can't beat the price. :thumbsup

I'm currently using one on a Hal 9000.
[/b]

Great find. I don't think I even knew Walmart had a magazine section. :$ Off to Walmart I go.

 

[NakedMoleRat]

[/quote]
How's this for the resistor? It's the closest I could find on the shack website to 120 ohm
http://www.radioshack.com/product/index.js...rentPage=search
[/quote]

That should work well enough. It will cut the light down just a bit more. If you walk into a radioshack they will have a 120ohm. The color code (brown, red, brown, gold) means that there will be four stripes on the resistor, the colors will be in that order and that's how you can tell it a 120ohm. You'll probably get a pack of five for $1.30 or something like that.

You could use the booklight, but you would need to replace the switch for your purposes. It should be easy enough to do so. If you want to go that route, buy the booklight first and take it to Radioshack and have them help you pick out a switch for it.

Edited to replace the work nightlight with booklight,,duh.

 

[Sulla]

Thanks everyone for all your help.