(If you like this project, consider voting from me in the make to learn contest, and the up! 3D printer contest, thanks.)
Coils are used for an abundance of projects, but are not very easy to make. Often, coils require 100's and sometimes 1000's of turns. Doing this by hand is extremely difficult, so I made my own coil winding jig that uses a pedometer to automatically count how many turns the coil is. (NOTE: I used MY Solidoodle 3D printer to manufacture many of the parts used to build this jig. A 3D printer is not necessary but will make the project easier to build. I will also include the 3D files.)

Intro

What did I make?

I made a manually operated coil winder that takes advantage of a cheap pedometer and a micro switch to automatically count how many turns are in the coil.

How Did I make?

This project came about when I was creating my science fair project ( a windbelt) and realized that I needed some custom coils. For me, the best way to solve this problem was to create a jig that would make winding coils easier and would automatically count how many turns are in the coil. A plus was that I did not have to buy any parts. Everything in this project can either be found at home, or bought really cheaply.

Where did I make it?

I made the coil winder at my house. Since I needed more space for this project I had to use my basement as a workshop and my ping pong table as a work table. Some members of the household dislike my use of the ping pong table, but I told them that science takes precedence over ping pong :)

What Did I Learn?

Well, there are many things to learn in this project. 3D printing precision parts is challenging with a $500 3D printer, but my Solidoodle held up great! I learned very quickly that it is important that you put glue on the coil as you're making it, or else it may fall apart in the end. I also learned that you do not have to sacrifice functionality for style, to the average person it may look like a machine, but to me it's a piece of art :)

Step 1: Materials

4 - 1.5in x 3/4in x6in stanchions
1 – 3/8in hex bolt
1 – 3/8 hex nut
1 – 3.5in x 3/4in x 13in wood plank
8 – 1/8in wood screws
2 – 1/16in eyebolts
2 – rubber bands
5 – 1/8in x 3/4in screws
1 – low cost pedometer (very important, must be a cheap pedometer)
As needed – electrical wires
3 – 1/16in bolts
3 – 1/16in nuts
1 – micro switch (other switches/ buttons may also work)
1 – 1/4in x 6in bolt
5 – 1/4in nuts
1 – 1/2in wde x 1/2in tall metal spacer (size depends on how tall you want the coil)
2 – 1.5in OD 1/4in ID washers (size depends on how wide you want the coil)
1 – 1/2in washers
1 - 1/2in ID washer
Copper enamel wire
Assorted printed parts
(http://www.thingiverse.com/thing:56493 All the printed parts can be found here!)

Step 2: The Coil Side

These steps are taking directly from my science fair project so they might be a little overly complicated.

1. Pre-drill two 1/8” holes about 3/8 of an inch from the bottom a stanchion so that the holes are next to each other.
2. Repeat step one for each of the four stanchions.
3. Drill a 3/8” hole in the middle of two of the stanchions 3 ½” from the bottom. These will be the back stanchions.
4. Insert two 1/8” woodscrews into the predrilled holes in each stanchion and fix two of the stanchions to one end of the base board.
5. Fix the other two stanchions to the other side of the baseboards, about 1” from the end.
6. Attach two 1/16” eye bolts to the baseboards ½” from the side of the baseboards, and about ½” from either side of the stanchion.
7. Print out part finalweight4.gcode
8. Attach rubber band on each side of printed part and secure the other end of each rubber band to the eye bolt.

Step 3: Front Side

9. In the front two stanchions drill a ¼” hole in the middle of the stanchions 1” from the top.
10. Print out wirejig3.gcode
11. Insert a 1/8” washer onto an 1/8” screw. Insert the assembly through the top hole in the printed part.
12. Insert a 1/8” washer onto the other side of the screw, then rotate the printed handle onto the screw. The handle should move freely.
13. Slide the wire jig handle assembly onto the ¼” bolt.
14. Slide the bolt through one hole of the front stanchion, but not both.
15. Rotate a ¼” nut onto the bolt so that it is 1” away from the stanchion.
16. Print out Cam2.gcode
17. Slide the cam onto the bolt so that it is next the nut.
18. Drill a 1/16” hole about 1/8” from the center of a 1 ½” diameter washer.
19. Slide the washer that is not drilled onto the bolt so it rests against the cam.
20. Slide the spacer onto the bolt so it rests against the washer.
21. Slide the drilled washer onto the bolt so it rests against the spacer.
22. Rotate two nuts onto the bolt so that they both rest against the drilled washer.
23. Slide the bolt though the hole in the other stanchion.
24. Rotate a nut onto the end of the bolt so that it secures the bolt against the stanchion.

Step 4: Switch and Stand

25. Print out part lever2.gcode.
26. Drill a 1/16” hole through the handle of the lever.
27. Insert the lever over the micro switch so that the holes line up.
28. Insert a 1/16” bolt through the lever and the micro switch and place a nut on the other side.
29. Open up the Pedometer to get a look at the inside.
30. There should be two distinct metal contacts and a lever that can connect and disconnect them.
31. Remove the lever and solder a wire to each of the contacts.
32. Solder the end of one wire to the “common” on the micro switch, and solder the other wire to the “normally open” on the micro switch.
33. Print out switchstandnew5.gcode.
34. Fix the Switch to the stand by drilling two small holes in the plastic and inserting two 1/16” bolts through, and securing with two 1/16” nuts.
35. Position the switch stand on the baseboard so, when turned the cam pushes down the lever on the switch.
36. Insert four 1/8” wood screws into the slots on either side of the switch stand.
37. Set the pedometer into the box on the switch stand.

Step 5: Make Some Coils!

38. Slide the coil of wire onto the 3/8” hex bolt, and tighten the nut on the end.
39. Pull the wire though the hole in the washer and pinch it between the two nuts.
40. Set the pedometer to 0 and start winding away!

And if I haven't mentioned it before, the plastic arch like piece is designed to fit over the coil of wire and apply pressure to it to keep the wire taught. have fun!