More coils

Here I have started to wind the solenoid coils using 0.25mm diameter magnet wire. A 25g spool filled up 4 solenoids nicely, I didn't worry about counting the number of turns.

The winding jig was very simple. Just a crank handle made from a couple of 3mm screws and a scrap of 2mm aluminium. The bolt in the vice is being used as a pin, the thread isn't being used. The spool of wire is being held behind a couple of bits of steel, ground parallels in the case, this keeps a bit of tension on the wire. I just used my finger to guide the wire to get an even distribution. The winding took about 2 mins per coil.

After winding I soldered longer wire leads to each of the enamel wire endings. The soldering process removes the enamel, so you don't need to worry about scraping it off. I used some shrink tube to protect the join.

After successfully winding 6 coils, that brought the total to 8 including the prototypes. Enough coils for a single octave and a good chance to test out playing some songs.

Here is a fast version of the "doe a deer" song from The Sound of Music. This was about as fast as I could play with the first prototype coil. It required a 100ms pulse while the later design with more windings only needed a 7ms pulse to get a note to ring. So when all the coils are wound it will play about 14 times faster than this, which, after a little test, is ridiculously fast.