The Lowly LED, A Primer

[asnider123]

The lowly LED (light emitting diode)adds an indicator to your DIY mod that shows that it is functioning properly. In it's simplest configuration, the LED goes directly across the atomizer connector.

Make sure you use a resistor on one leg of the LED (contrary to popular belief, the resistor can go on EITHER leg). LEDs will shine brightly for a bit then burn out if a resistor is not used in series with the LED. The resistor's function is to control the amount of current flowing thru the LED. For general use, a 420 ohm resistor should suffice though some people prefer slightly lower resistance (like maybe 220 ohms), which will give you brighter light output but will also reduce the life of the LED.

Your LED will normally have 2 leads coming from it. The longer lead indicates the positive side, the shorter is negative. Does it hurt to put the LED in backward in a circuit? Normally No, but it won't work, as an LED is a diode, meaning it will only allow current to flow one direction.

Bi-color LEDs will normally have 3 leads, the center being B+, the longer of the outer leads one color (the dominant color) and the shorter will be the other (non-dominant). Both outside leads will be B- (negative). With a bi-color LED, only one resistor is required, as only one of the 2 diodes inside the LED will be on at any time. If both outer leads are activated, the dominant takes precedence. My LEDs, for example, are red/green 3mm LEDs. I use Green to indicate my master switch is on, the red when the atty gets power (when you vape). I use this configuration to remind you that the master switch of the PV is turned on (green) and that you should start inhaling when red.

LEDs are probably the least expensive addition you can make to a homebrew mod, and one of the most important. I use that Ebay place for all my LEDs and most other electronic parts, I get it all from the Orient. Takes a while, but who's in a big hurry anyway?

In fact, except for the atomizer connector, everything you need to build a boxmod (including the box) can be bought way cheaper on Ebay from places like Vietnam, China and Hongkong. If it weren't for the 510 or 801 connector, my mods would be completely made from Ebay parts (including batteries and charger).

So ends the lesson for today.

More questions about LEDs? Post your questions in this thread.

 

[ouada]

good stuff

 

[asnider123]

ouada wrote

How would you make a bi-colored led one color when the pv is on, and the other when you fire the atty?

With my mods, I use bi-colored LEDs in conjunction with N-Channel MOSFETs. The FET has one pin that's B- when the master switch is on, the other B- only while vaping.

I will do another primer shortly on how to make a mod using the 3103 MOSFET. It should become clear as you study the MOSFET Primer.

Thanks
Alan

 

[ouada]

thanks asnider

 

[groundedcontrol]

Hi. After running a battery much lower than intended in my REO, I briefly considered throwing an led indicator into the circuit to show when the battery is low. I thought I might just rip one out of an old 510 penstyle, and connect it to the spring mounting screw, and the switch spring, but then I realized this wouldn't work (LED would light on completing circuit, but would not . Is there anyplace which simply sells a small battery indicator led? but I was wondering if anyone knew of something simple which would do the trick. I don't really want to put a limit on the length of my draws, I just want a way to be reminded when my battery is getting below 3.3v without having to break out my multimeter.

Are led battery indicator kits available for sale anywhere? My google-fu is weak tonight, and I've turned up nothing of use.

EDIT: yes, I know it sounds silly to add anything to the REO, but I'm hoping I can get something functional that will be easy to remove and replace without soldering, and not permanently alter the REO. I just want to avoid killing my batts, and this seems like it would be an easy way to do that. I don't know much about circuits, and I'm not even sure that such a thing would work if wired parallel to the 510 connector. I can't figure any way to get it in series, and so if that's the only option I'll happily abandon this idea.