Blinking accent LEDs

[Moordak]

Hey guys,
I've got a saber in progress that has two 3mm accent LEDs mounted on a control box. Right now I have them wired up resistors and they are on constantly. I just had a thought that I'd like to make them blink.

With that, does anyone know of an easy way to do it? I'm going to guess that a capacitor of the right capacitance & voltage might suffice? I'm running 4.8v of rechargeables.

Thanks!

[xwingband]

Capacitors just hold a charge... you'd maybe bet a fade with the right size one, but it would still be on/off.

You can buy blinking LEDs. You should look those up.

[Moordak]

I had thought of just using blinking LEDs, but hadn't found any in white yet. I'm using a white and a green one. Also, I wanted to somewhat be able to control the rate they blinked at and stagger the blinking so they weren't at the same time. Though I may end up just getting a blinking green and leave the white on constant if I have to.

[Klaatu]

You would need to use a microcontroller for that. You can get microcontroller for super cheap/free. however the programers can be a little salty. you can get a pic microcontroller for free and the USB programer for like 15 bucks on ebay. A transformer will call the LED to flicker. So if you would prefer a flicker over a blink your can try that.

[Moordak]

Thanks for the ideas. After some more searching on The Google Interweb I found a small control board that will randomly or sequentialy flash up to five LEDs. I think it'll work nicely for a future saber.

[Klaatu]

do you have the link. that might come in handy for a lot of us.

[vadeblade]

A micro-controller or a controller board is overkill just to make accent LEDs blink.

Buy one 555 IC chip and a bunch of resistors and capacitors to do the same thing. Change the value of the capacitor or resistors to change the frequency of the blinking.

use this circuit layout:
http://i258.photobucket.com/albums/hh258/vvvv_767/blinking-circuit.gif

How to use capacitor value or resistance value to control the 555 chip.
Capacitor - higher Capacitance (uF) = slower blink, lower capacitance = faster blink
Resistor -Higher Ohm = slower blink, lower Ohm = faster blink.

NOTE: Input voltage will also effect the blink frequency. Example - if 3V input = 1 second between blink, 6V input = 0.5 second between blink.

The whole thing can be made for 5 bucks and will be the size of a thumbnail. Cuircuit board in not even necessary - just solder resistors and capacitors directly to the IC legs.

I built something similar for a different application - Electronic Airsoft Grenade.

EDIT: Here is youtube video showing 555 chip used to make Blinky LED - http://www.youtube.com/watch?v=ncqAEmkH2OY
see how small it is???? Ignore the other electronic stuff on the other end of the breadboard in the video.

[Moordak]

Awesome. Thanks for that info Vade.

[vadeblade]

your welcome. Some additional clarification...

(please refer to the picture I provided)

To change blink frequency change One or More of the following:
Resistor between Pin 7 and 8
Resistor between Pin 6 and 7
Capacitor between Pin 6 and Ground.

and finally if you need to get more clarification on how to build there are MANY examples on Google but you want examples that use the 555 chip in "astable" mode.