Introduction: Magnet Activated Led Pen
A handy Light in a pen activated by a magnet. Easy project
Step 1: Materials
What you need:
- electrical tape
- 3/16 in drill bit
- LED about 2.7v
- expo marker
- exacto knife
- reed switch
- soldering iron
- 9v battery
- wire cutters
- needle-nose pliers
- about 26ga red wire
- black sharpie
Step 2: Dissasembleing
Carefully cut the edges of the 9v battery off to reveal 6 AAAA batteries. Cut two off from the group and be sure that they are connected by metal at the bottom and it would be helpful if there was metal sticking out of the other sides also.
Take your needle nose pliers and remove the end cap and ink cartridge from the back of the marker.
Step 3: Casing
Solder the negative end of the battery pack to the reed switch with the red wire .The positive end has a piece of metal left on it from the 9v battery, if not quickly solder on a strip of tin. Making sure that the end of both pieces of metal are the same length, wrap the bundle in electrical tape (you may also apply a layer of scotch tape for a better fit).
Step 4: LED Placement
use a sharpie and color a wire black (about 3 in) and leave another red. solder one black end to the reed switch (+) and the other end to the cathode part of the LED (the side with the short wire or flat side). solder a red end to the strip of metal (-) and the other end to the anode side of the LED.
Step 5: Assemble
Insert pack as far back as you can with a pencil. Drill a hole in the end plug so that you can fit the LED through it. Leave the LED in the cap and carefully roll up the wire and fit the cap on.
Step 6: Finished
Now that you are finished try it out by putting a magnet by the marker and the LED will, if you did it properly, turn on.
Of course there are many variations of this project. you could use different colored LEDs. (I used red because that's all they had at Radioshack at the current time.) You could use UV LEDs in a highlighted because yellow halters glow when exposed to UV light. I would like to see that.
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