Stop fumbling around for a 3V battery, build your own LED tester, and freshen your breath while you are at it!
Let's get started.
Step 1: Materials
- Altoids Smalls tin: ~$1.50 at a drug store. Or buy them in bulk on Amazon.
- (1) Wire Housing: $0.13 at Mouser.com
- (2) Wire Header: $0.14 each at Mouser.com
- 3V Coin Cell Battery: Find them for cheap on ebay.com
- Coin Cell Battery Holder: $1.56 at Mouser.com
- (2) Small Pieces of Hookup Wire
- (1) Rubber Grommet: 1cm across, can be found at any hardware store
- Dremel Tool or Rotary Device
Step 2: Individualize the Wire Headers
Find the two metal wire headers, and fold them back and forth until they are apart. In order for these to fit in the plastic housing, you will have to take some wire cutters and trim the edges of the header.
In the picture below, I have noted what you will need to trim off on the headers in order for them to fit in the housing.
Step 3: Some Soldering
Take your first piece of hookup wire, and solder it to the portion of the wire header that has a lane for the wire to rest in. Solder that wire down, and then if you can, crimp it.
Do the same for the other wire header as well. You should now have two wire headers with two pieces of hookup wire attached to them.
Step 4: Some More Soldering
Now solder the opposite end of each hookup wire, to leads (or holes) on your 3V Coin Cell Battery Holder. Make sure the 3V battery is not in the holder during this step!
Since most of the LEDs that I use are safe with just the 3V battery, I did not add a resistor. But if you have LEDs with a lower voltage drop, then there is definitely enough room inside to add a resistor. To add a low Ohmage resistor, connect it between the negative lead on your battery holder, and the wire header thatis connected to that piece of hookup wire.
Step 5: Drilling and Securing
Now take your rotary tool and drill a hole roughly 75% of the total circumfrence of your rubber grommet. Drill one small hole intially, and then, as needed, make the hole bigger so that you can easily but snugly fit your rubber grommet in the hole.
The rubber grommet (for those who don't know) should have one half sitting on top of the Altoids tin, and one half sitting on the other side.
Now take your metal wire headers, and place them into each hole on the plastic, white wire housing. You should be inserting the headers into the side that has the pattern set for the headers. (Not the side with just the rectangles.)
Be sure that the headers are securely fastened inside of the plastic header.
Now take the plastic header, and poke it through the rubber grommet on the Altoids tin. The side with just the rectangles should be facing outwards.
Step 6: Testing
Insert a 3V coin cell battery into the battery holder, secure everything inside of the tin, close the tin, and you are done!
Find an LED with a forward voltage of around 3V, and test it in your new Minty LED Tester!