$1 LED flashlights & cheap tools

[amz-fx]

First, the sale is back on at Harbor Freight so if you missed the stepped drill bits or the $2.95 multimeter, now is your chance.

Next, here is something I found yesterday which is very useful.  A white LED flashlight for only a buck!  I've already used it when reconnecting the wiring on the back of my TV and it works great with no real hot spots.  Can't beat it for one dollar!  The unit is available in several different body colors and I bought it at The Dollar Tree.

What do you do first when you buy something new and cool?  You take it apart, of course!  It appears to be merely 3 AAA batteries in series driving the white LEDs which are in parallel...  just about the worst configuration possible.  I expect that at some point the LED which is drawing the most current will burn out!

A suggested mod:  add a 56 ohm resistor in series with one of the wires going to the back of the LED circuit board...  doesn't matter which wire.  The LEDs will not be as bright but they will not be in danger of burning out either.

regards, Jack

[Roobin]

Looks cool. LOL

What do you do first when you buy something new and cool?  You take it apart, of course! 

I'm planning on doing up my wardrobe with bright LEDs, with an automatic switch so it comes on when you open the boor.

[theblueark]

Looks cool. LOL

What do you do first when you buy something new and cool?  You take it apart, of course! 

I'm planning on doing up my wardrobe with bright LEDs, with an automatic switch so it comes on when you open the boor.

This is why i freaking love diy 

[markm]

I saw something similar to this light from one of the tool distributors selling for $13!
Looked like the same light though 

[RLBJR65]

Those $2.95 multi meters at Harbor Freight are a great deal. I bought one it was off a bit on resistance and DC voltage but not much.
What surprised me is that it tested transistor hfe as good as my $150.00 meter!

[Hiwatt25]

What the heck is harbor freight?  People here talk about it but I've never seen one.  We do have travelling "tool sales" that breeze into town from time to time but I don't know it that's what you guys are talking about.

Also, what's a Waffle House and a Sonic?  I've never seen either one of those either.

[jonathan perez]

whats an LED Bulb?

[Barcode80]

Harbor Freight = online retailer which sells a lot of stuff we use around here.

Sonic = fast food chain, home of the best damn bacon-egg-cheese toaster sandwich money can buy

Waffle House = restaurant, home of the worst food you can get 24 hours a day. IHOP is better.

[jonathan perez]

Waffle House = restaurant, home of the worst food you can get 24 hours a day. IHOP is better.

and thats not saying much for IHOP...

[RLBJR65]

Harbor Freight has all kinds of discount / off brand tools and other misc. You can order on line. http://www.harborfreight.com/
Waffle House seems pretty damn good at 3:00am after you close a bar down

[MartyMart]

Jack ... that's so funny , I can see it now "The AMZ LED Flashlight mod E-book" download for 25c !!


Marty 

[amz-fx]

Jack ... that's so funny , I can see it now "The AMZ LED Flashlight mod E-book" download for 25c !!

Coming soon to a website near you! 

Definitely one LED is getting more current than the others as there is a visible difference in brightness if you look straight into the end...   one LED is brightest, one is bright and the last is noticeably less bright.  With a fresh set of batteries I would bet that the brightest LED will soon burn out.

I'll do the mod to add  the resistor and post another picture...  56 ohms is probably the most you would want to use and 10 ohms would be the lowest additional resistance to try.

regards, Jack

[stm]

If the flashlight were using 3xAA batteries I would bet the LEDs might burn out, however the button cells have a rather large internal resistance, so I'm pretty sure that current is already being limited to a reasonable value, most likely not exceeding 30 or 40 mA in the worst case.  This could be checked with a tester connected as an ammeter.

LEDs have life ratings in the order of 10000 to 50000 hours, and in some cases up to 100000 hours.  If you consider a small flashlight that will be used probably for a few minutes a day, it doesn't really matter if the LED life is shortened down to as little as 1000 hours.  This still gives several years of usage, and with higher light output!

Considering the one-dollar replacement cost, this is not necessarily a bad design choice!  An extra resistor adds to the material and assembling costs while reducing light output.

The real challenge is not loosing or breaking the flashlight before the LEDs die out!  This is a bit like using BIC pens, how many times have you been able to use one since it is new until ALL the ink is exhausted?