Magnetic Pickup Instructions

Warning!:  This would be an easy project if it were not for the extreme fragility of the wire you will be working with.  It is very easy to break, even when you are aware of how easy it is to break, and you're trying not to break it.  You can do this, but you have to be very careful.

Summary:  You will be using very, very, very thin and fragile wire to create a coil with thousands of turns.  The ends of this wire will be sanded and soldered to stronger wire, and all of the fragile wire will be encased in hot glue.  When this coil is held next to a vibrating steel guitar string, in the presence of a magnet, electric current will run back and forth in the coiled wire, keeping time with the string vibrations.  If the free ends of the wire connect to an amplifier and a speaker, you will hear the sound of an electric guitar.  The coil is called a "pick up," and it is functioning as a generator -- a gadget that uses a moving magnet (the magnetized guitar string) to create electric current in a coil of wire (or the other way around -- moving coil, stationary magnet).

Materials:

1. Hot glue gun + glue

2. Scissors

3. Note Card or manilla folder

4. Pen or pencil

5. A rotary tool (Using a drill may reduce your chances of a disaster, but a Dremel is faster and quieter)

6. Flat head nail (If you want to use a Dremel to wind your pickup, find a nail with a 1/8" shank)

7. Clear tape

8. Fine sandpaper (150-250 grit)

9. Flexible and thin, but strong, stranded insulated wire (in the range of 18-22 gauge).

10. Soldering iron and solder.

11. Fume extractor/fan

12. Optional -- multimeter

Directions:

Part 1 -- Making the Bobbin:

1. Heat up  a hot glue gun.  You will need it later
2. Draw two 1" diameter circles (size of a quarter) on a note card (or other cardstock).  Mark their centers with a dot.
3. Cut out the circles
4. Poke a small flat head nail (a thin enough nail to easily snip off later) through the centers of both of the circles. 
5. Slide one circle so that it butts up against the nail head.  Apply a little hot glue to glue the nail head to the circle.
6. Slide the other circle so that it is about 1/2" from the other circle.  Glue this circle SECURELY to the nail by applying glue to the nail on the side of the circle that is farthest from the other circle.
7. Use scissors to snip a tiny slit (no more than 1/8" long) perpendicularly into the edge of the circle by the nail head.  Now your "bobbin" (the name for the coil housing) is complete.

Part 2 -- Preparing to wind the bobbin:

8. Insert and firmly tighten the free end of your bobbin's nail into the jaws of your rotary tool.
9. Clamp your rotary device (drill or adjustable Dremel) to a table top, with the rotary part hanging off of the table.  Make sure that you can easily access the speed controls.
10. Get a 3/4" long piece of tape ready to go.  You will need it soon.  The picture below shows masking tape, but clear tape seems to work better.
11. Place the spool of magnet wire (36 gauge or higher) directly below the bobbin.
12. Grab the free end of the magnet wire and pull it upward toward the bobbin.  Make sure that it is moving freely.
13.  At a point about 4" from the end of the magnet wire, pass the magnet wire through the small slit that you made in the bobbin.  Pass it through the slit in a direction from inside the bobbin to outside (toward the nail head).
14. Carefully stick the extra 4" of magnet wire to the 3/4" piece of masking tape that you have prepared.  Then stick the tape to the outside of the bobbin, covering the nail head.  You will need this wire later, and the tape will keep it safe and out of the way during winding.

Part 3 -- Winding the bobbin:

15. Grasp the magnet wire a few inches below the bobbin, holding it very lightly.  Next begin to accelerate the rotary tool at its lowest speed.
16. Once you get the bobbin rotating, and the wire is passing easily through your fingers, your job is to simply direct the wire to parts of the bobbin that need it most -- while applying the smallest possible force.  If you grab too tightly you will break the wire.  This will take a while.  Try to stay focused until you're done.
17. Keep winding until the level of the wire almost reaches the end of the 1/8" slit that you made in the bobbin.  Then stop.
18. Carefully remove the masking tape to free the other end of the magnet wire.
19. Grasp the other end of the wire (going to the spool) carefully, and slide it through the slit, in the same way that you slid the free end of the wire through the slit.  Measure out at least 4" of wire and cut it off.

Part 4 -- Preparing to solder the thick wires:

20. Carefully remove the bobbin from the rotary tool and place it in a safe location.
21. Cut a couple 1' lengths of heavier stranded wire (heavy enough to stand up to some abusive tugging, but light enough to be flexible -- stranded wire around 20 gauge is good).
22. Strip the ends of the stranded wire.  About 1/2" is a good amount to strip.
23. Get the bobbin and gently sand the ends of the fine magnet wire.  Place the wire flat on a table, with its end pointing away from you.  Press down on the end lightly with the sandpaper and sand with a motion away from your body.  Lift the sandpaper between strokes.  Depending on the color of your wire's coating, you may not be able to tell that you're achieving anything.  Trust your instincts.  I suggest that you don't try to roll the wire around to sand multiple sides; it's too easy to break.
24. Set up your soldering area.  You will be soldering directly on the table surface, so make sure that the surface can handle this.  If it's a nice table, cover it with a board of some sort.  Assuming that you're using lead solder (which seems to work best), either solder outside or have a fume extractor ready to go.  Or at least have a fan to disperse the fumes.

Part 5 -- Soldering:

25. Carefully move your bobbin and thicker wires to the soldering station.
26. Very gently wrap one of the sanded ends of your magnet wire around the stripped end of the stranded wire.  I have broken multiple magnet wires at this step.  That is why I have leave at least 4" of free magnet wire to work with.  If you break it, you can sand the new end and try again.
27. Lay the wrapped connection on your table surface.  Place your heated soldering iron at the junction.  Add solder until the entire junction between magnet wire and stranded wire seems to be drenched.    Don't breathe the fumes from the solder.  They contain lead!
28. Repeat this with the other stranded wire.
29. If you have a multimeter it would be good to test for continuity at this point.  By continuity I mean a conducting connection from the free end of one stranded wire to the free end of the other.  Normally I would use the continuity tester setting to do this, but the resistance is so high that the continuity test setting shows a false negative (at least on my multimeter).  However, if I set my multimeter to read resistance, I get a very high reading (on the order of 1,000 Ohms). The fact that I get a reading means my connections should be good.  If I got no reading at all, I would probably sand some more of the wire, wrap it around the soldered section, and re-melt the solder.  If you don't have a reliable multimeter, proceed and hope for the best.

Part 6 -- Final Preparations (encasing with hot glue):

30. Now carefully remove the wires from the slit.  Then very carefully wind them around the bobbin, on top of the rest of the magnet wire. 
31. Separate the wires, so their conductive parts (sanded or soldered) don't touch one another!  I think we have been getting some short circuits.
32. While the glue is still liquid, avoid the temptation to wrap the wires tightly.  You are likely to break the magnet wire unless the ends of your thick wire are already secure in solid glue.  Just take up the slack.
33. If you have a fan, turn it on at this point.  You can use it to speed up the cooling of your hot glue.  The fan of a fume extractor should work.
34. Finally, with as much patience as you can muster, cover all of the magnet wire, plus at least an inch or two of the stranded wire, with hot glue.  Be prepared for your hot glue to drip.  Don't let that wreck your pickup.   If you have a fan going, use it to cool and solidify your hot glue.

Part 7 -- Testing:

33. Your pickup should now be complete.  To test it, connect the free wire ends to the provided speaker/amplifier, via the alligator clips of the black aux cord. 
34. Turn on the speaker and hold your pickup next to the string of the example electric guitar, with the nail head pointed toward the string.  Then pluck the string.
35. If you hear amplification, it works!  If you don't, check your pickup's resistance.  If you can't measure the resistance, you probably need to start over. :-(  That's not unusual.  Just don't waste time feeling sorry for yourself!  Your next attempt should be better.