Instructables

LED flashlight for under $10 (solderless, flat)

Picture of LED flashlight for under $10 (solderless, flat)
This Instructable will show one how to build a LED flashlight without solder that will lay flat for under $10. The idea for this came from a need to have a flat flashlight that would not roll around when I was working on computers and wiring for my tech support business. Also, I needed something that could be inserted into narrow places, like behind furniture and inside computers. Since I could not find any flashlights that would be able to do these things, I decided to imitate the Free Software/Instructable Communities and build one to my specifications. For the construction of the circuit, many of ideas came from other LED flashlight Instructables on this site. A basic schematic is below.
 
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Step 1: Assemble your parts and tools

Picture of Assemble your parts and tools
stepone.jpg
Many of these parts can be found at Home Depot, Radio Shack and 99 Cents stores.
Parts from Home Depot:
1. One foot of Cat 5 cable (split for 20 gauge wire), Part #: 709489: 27 cents
2. Wood shims, Part #: 091-996-002-0000: $1.09
4. Electrical Tape, Part #: 0-775-78-03-777-6, 59 cents:
5. Light switch, Part #: 078-477-772-713: 64 cents

Parts from Radio Shack:
1. two - 5 mm high brightness white LED, Part #: 276-017: $1.99
2. AAA Battery Holder, Part #: 270-398: 99 cents

Part from Jack's 99 Cent Store, 32nd St. between 6th & 7th Ave, NYC:
1. 2 AAA Batteries: 99 cents
2. One 8.5x11 piece of paper: 1 cent

Tools:
1. #2 Phillips head screwdriver
2. Wire cutter/stripper
3. Scissors
LED-Flashlight.pdf(794x842) 90 KB

Step 2: Connect the battery box to LED

1. Twist the red wire on the battery box around the positive (longer) terminal of the LED light.
2. Take a piece of 20 gauge wire and strip both ends, about 5 inches long.
3. Twist the 20 gauge wire with the stripped end of the black wire from the battery box.
retzlar8 months ago
this may be a dumb question.. but how do you connect multiple LED lights? I want to have a series of them powered by a switch and AA batteries.
matt392 (author)  retzlar8 months ago
No, it is a good question. I will try to do an Instructable in the future that connects 2 LEDs. I did it in the past; IIRC, you chain them together by connecting the negative wire of one LED to the positive wire of the next one with a wire. But I will have to confirm that for you.
Hi, I just posted a question, looking for help with just such a project as this. If I understand this instructable, I can just get the LEDs, as you have used here, and wire them into the existing AAA circuit, without any sort of resistor? Thanks!
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jsilvers12 years ago
i wonder if u could add a solar panel to this to charge the battery and still have the on/off switch so that u can turn the light when u don't need to use it
marc925 years ago
I believe it would be possible to make this light much smaller to better fit in the places described.
This could be done smaller very easily, with junk computer parts, or just other electronic junk one accumulates. The switch you are using will cause more battery run down than a much smaller switch better suited to the amount of current you need to run an LED.
matt392 (author)  Chiana_Rei5 years ago
One of the design goals was to be able to build it with common, inexpensive parts from retails stores like Home Depot and Radio Shack.
Radio shack definitely sell the simple parts that'd make this project much more efficient
matt392 (author)  lifelong-newbie4 years ago
Keep in mind, part of the design goal was to keep it under $10.  Radio Shack definitely has good parts, but they may have pushed it above $10.
matt392 (author)  marc925 years ago
The size makes it easier to position since something smaller might get dropped into crevices and the like.
ATG marc925 years ago
if 3v button cells r used in serie...this thng can fit into a matchbox...
marc92 ATG5 years ago
With the obvious exception of the light switch