I need thumbs! (And stupid questions answered)

[MastiffMike]

OK, first let me say I absolutely SUCK at soldering! You wouldn't believe how hard it is to do with paws!

Here's the background before my really dumb questions:
I've spent the last *cough*1-1/2 hours*cough* trying to solder some LEDs and when I thought I was all done I tested and they didn't work. So I ripped em out and tried again, also with unsuccessful results (though the second time one of the LEDs worked, but not both). I'm working on an all mechanical, no solder, mod and idiot me decided sorta last minute to put a couple LEDs in it!. There was a REASON it was supposed to be all mechanical! Basically what I'm attempting to do is wrap 2 LEDs around a 510 connector and I don't have much space to work with, just the height of the connector that's inside the base. Anywho, my attempts were NOT pretty (they're not going to be visible so I'm OK wih that) but they seemed solid and I got it all to fit. However, I musta messed up somehow and thus my studpid question:

When wiring 2 LEDs can I get away with 1 resistor? Ideally since space is so tight I'd like to connect the LEDs together and have them share leads from the battery and a resistor. Prior to soldering and fitting them into my space I tested 2 LEDs with one resistor and they worked, but should I use 2 seperate resistors? How sensitive are LEDs anyway? Maybe I got them too hot while soldering and that's why they don't work? My connector is inside a "tube" (for lack of a better description) and there's literally only enough room along side it to squeeze an LED. I'm placing the 2 LEDs on opposite sides of the connector (picture one at 12 o'clock and one at 6 o'clock, with both facing towards 3 o'clock and my battery leads coming in from 9 o'clock - clear as mud? ). I know I didn't have a short but maybe while bending the leads I fubared them?

Appreciate any thoughts, ideas, advice, namecalling, pleas for me to give up, etc.

 

[TomCatt]

I have some thoughts, ya know, like "ummm" and "duh" and even "hmmm"; but that's all I have. So this is just a bump for ya Mike.

 

[MastiffMike]

LOL, thanks Tom! I'm starting to think that the LEDs are just beyond my ability (and LEDs "should" be the easy part!).

 

[CraigHB]

In general, it's a bad idea to parallel any diode including LEDs. The reason is that diodes lose forward voltage drop as they heat up so the one with the lower drop to start will carry more and more of the burden current as it heats up (no two diodes are exactly the same due to normal manufacturing tolerances). Practically speaking, one will brighten and the other will dim out. If there is enough difference, one of them may not even light up at all.

You can probably "get away with it" if the diodes are exactly the same. It definitely will give you trouble if they are not. You also need to cut the bias resistance in half since you are doubling the current.

It would actually be best to connect them in series and adjust bias resistance accordingly. Though, that will only work with series cells since you need at least 5V to properly bias and light the both of them.

 

[MastiffMike]

Thanks Craig!

So let me see if I understand things correctly (I'm willing to put 2 more hours into wiring up the LEDs but any more than that I'm I'm going to scrap them - they were never part of my original design anyway):

1. If I use 2 LEDs I should try to cram 2 resistors in there so that each is wired seperately.
2. Since the mod uses only one battery (and is only 3.7v) series wiring is not going to work either.
3. Since once I put the bottom plexi panel on I will NOT be able to access the LEDs, I MUST do #1 or risk premature failure without a way to fix it.

So now I have to decide if 1 LED will be bright enough to edge light the plexi or do I try to fit 2 (with 2 resistors) or do I scrap the whole LED idea!

 

[MastiffMike]

YIPEE!

I can't believe I did it! I FINALLY (after 3 tries and roughly 4 HOURS!) got it all to fit and work! It's NOT pretty, but it's all enclosed and not visible so as long as it works I'm happy!

NOTE TO SELF: NEVER again decide to put 2 LEDs, 2 resistors, HS tubing, a 510 connector, a pound of flesh, a dallop of pride, and a chunk of my soul inside a 1/2" pipe that's only 3/8" long!

Now I can finally move on to the final manufacturering piece (the main body) since the end pieces are now completely done except for paint. I may yet finish this by 2013!

 

[bamsbbq]

i just want to see if anybodies soldering looks like mine did...mine was so bad i havent picked up an iron in nearly 20 years(i gave the iron away after that)...i have 99% of the parts to build a mod, besides of course a soldering iron....i have the desire..i also have the fear still..lol

 

[MastiffMike]

i just want to see if anybodies soldering looks like mine did...mine was so bad i havent picked up an iron in nearly 20 years(i gave the iron away after that)...i have 99% of the parts to build a mod, besides of course a soldering iron....i have the desire..i also have the fear still..lol

LOL, My soldiering experience is ZERO until I attempted my first mod build (that one was aborted pretty quickly as it became readily apparent that I didn't have the skills necessary!). That's why I originally designed this build to be all mechanical, to avoid soldering! It's only my stupidity that made me sorta last minute decide to add the LEDs - thus requiring soldering.

I'll get picks up as soon as it's all done, though NOT of my soldering. Besides, it's all hidden inside the unit and won't be visible when I'm done! Trust me though, NOBODIES soldering could look any worse than mine!

 

[AttyPops]

A) FYI - for those reading this... Craig didn't say you had to use two resistors (from how I read it)... just that the LEDs should be in parallel (side by side, not end-to-end). Of course, you may need to size the resistor depending on the input. Circuit prolly has plenty of punch assuming you put the resistor on the ground side.

 

[asdaq]

He did say 'parallel' though.

I think it didn't light up as the cathode/ anode of one or both got reversed somewhere along the way.

 

[KeithB]

You can use a heat sink on the LEDs when you're soldering them, they are heat sensitive. You could use an alligator clip or even a pair of needle-nose pliers if you have a third hand.

My soldering skills are nothing special but you may want to practice just tinning and soldering together bits of wire before your next mod attempt.

 

[MastiffMike]

A) FYI - for those reading this... Craig didn't say you had to use two resistors (from how I read it)... just that the LEDs should be in parallel (side by side, not end-to-end). Of course, you may need to size the resistor depending on the input. Circuit prolly has plenty of punch assuming you put the resistor on the ground side.

He did say 'parallel' though.

I think it didn't light up as the cathode/ anode of one or both got reversed somewhere along the way.

What i did was solder the LED positives together and the negatives together then I soldered a resistor from the lead to the negative battery end and the positive lead to the positive battery. The likely error of my first try was that I attempted to bend and fit things into my space AFTER the soldering (though I forgot to test them after soldering and prior to bending/fitting). My second attempt I got everything bent and fit into the space, removed it all and soldered it up and then tested and it didn't work.

You can use a heat sink on the LEDs when you're soldering them, they are heat sensitive. You could use an alligator clip or even a pair of needle-nose pliers if you have a third hand.

My soldering skills are nothing special but you may want to practice just tinning and soldering together bits of wire before your next mod attempt.

I think in both cases it's HIGHLY likely that I got the leads too hot (I'm terribly at soldering which means I'm also real slow and probably keep the iron on way too long!). I finally got it all to work (with 2 resistors) but I think it had to do with my paying extra attention to how hot the LEDs got (and not the fact I used 2 resistors). Looking at the attempt that worked, I notice that my solder points are also further from the LEDs than my earlier attempts. I imagine this wouldn't matter much if I was even mediocre at soldering, but when you're as bad as me (and really, NOBODY is THAT bad!) the extra distance and attention to heat buildup makes a difference.

The soldering practice makes a TON of sense, just that I never planned for this to HAVE soldering, much less so much jambed into so small a space! I could've been avoid all these problems if I'd just stuck to the plan!

 

[CraigHB]

When I first starting doing stuff with electronics (several decades ago), I had not yet learned the value of a variable temperature iron. I burned up a few parts back then. Those cheapo 25W pencils are around 800F. Anything with higher wattage than that is way too hot. 600F is all you ever need unless you're doing thick wires or other relatively large parts like battery contacts.

A basic $10 pencil does the job most of the time and they're readily available, but you don't realize the value of a variable temperature soldering station until you use one. With my iron set at the proper temperature, I can leave it in contact with a joint liberally and the part won't die from getting overheated. At least it hasn't happened yet. I suppose it's still possible to damage a part, but you'd almost have to do it intentionally.

 

[MastiffMike]

Not perfect but considering about the only tool I own is a dremel (a drill press or lathe woulda helped!) here's my first ever attempt at a "drip" tip. This tip isn't for dripping thus the small hole.

My camera sucks and the paint looks better IRL. It's a dark blue metallic fleck but it still needs the clear coats (the button has the clear so you can sorta see how shiny it's supposed to end up).

Anyone know what size o-rings to use on a drip tip? I made this without an o-ring and it seems plenty snug, but I could add an o-ring if I knew what size!

 

[Sicarius]

To clear things up a bit ... for my OCD ... a typical LED uses about 20mA to light up. That's about (P=VI) 0.08W at 4V. With a 0.25W resistor you can run at least three LED's before the resistor burns out so two would run no problem. Also two diodes in parallel may be slightly different in brightness, but not to the point where one would affect the other. A better arrangement overall would be to run them in series reducing the load (current) on the overall circuit.

My electronics may be a bit rusty - let me know

The mod looks good though and I would get one of those multipacks of o-rings at the" cheapy-store". That way you can choose the best fit.

A tip on soldering is to 'prime' the two things you want to solder (get each with a bit of solder on) and then do a quick meet and greet with the solder tip. Works everytime for me.

 

[bamsbbq]

Danco o rings at the hardware or automotive store # 60 i believe for a 510

 

[twohandedcreations]

do you have a full pic of your mod? what is the case that you mod'ed(if its not a secret)?

 

[MastiffMike]

do you have a full pic of your mod? what is the case that you mod'ed(if its not a secret)?

I'll post a more pictures when it's done. I haven't quite finished the bottom section (the part with the damn LEDs! Though everything is in and working, I still need to paint it). The "middle" section (the blue part in the picture) is interchangable so that I can use various size batteries and have different looks. I made one sized for an 18500 but I went with a spray plastic-dip (rubberized finish) and I'm not happy with how it turned out. I think the problem is that it's 10-15 degrees here and so I think the cold screwed up the cosistancy of it. I've made another 18500 middle section which I'm thinking I'll wood veneer tomorrow. BTW the blue one with the ribbing (18350 version) is done accept for another clear coat.

When I started making this I felt an 18650 was too big (since I'm used to 901 auto batteries!) and the whole thing (top, middle & bottom) with an 18500 is about the size of 2 18650 side-by-side. My original intent was always 18500 so that I can have decent battery life (not a huge concern for me though) and also have the option of using the Kick (with an 18350). Only during the build did I decide to make the blue 18350 version since I wanted to see just how small/stealthy it'd be and I had plenty of the parts lying around (there's not really much too the middle section, less than $2 worth of materials that I already had).

To answer your question about what the body is, well... it's a combination of a few different pieces/parts (mainly plastic since the only power tool I really have is a dremel! I also wanted to keep the weight to a minimum). The exterior is just textured plastic wrapped around the 2 tubes with some epoxy filling the gaps around the connection points. My plan is to see how I like it and if the plastic doesn't hold up well I'll look into finding a machine shop that can make the middle (if not all of it) out of aluminum. If that's too cost prohibitive, I do have some sheet metal I may attempt to bend but that's a last resort since I lack the skills to do a good job. Another option would be to just order some aluminum pipe in the correct size but again, there's cost and I'm on a pretty much zero budget!

I should be able to get it all done in a few days and I'll post more pictures then. I must say I've learned a lot about what I'd do differently next time (like no LEDs!) and hopefully you all with more experience can critique it and gimmie pointers for next time (lol @ me thinking there'll ever be a next time!).