With your servo unplugged, place your HalloWing and battery face down on the front body (the one without wings) and center it so the screen shows through the hole. Draw a line around the electronics with a sharpie.
Take your chipboard rectangle and glue it along this line with hot glue as shown. Check to make sure your HalloWing assembly fits nicely inside and is aligned with the window. If you need to redo it, a little 99% alcohol will help get the glue off.
You can let the thread dangle through the opening like I have it here, or thread it through the front hole so it's dangling directly below the eye.
Thread your servo wire through the hole in the bat wing piece. Your servo will live on the outside of the bat on the back. Plug the servo into the HalloWing and push most of the wire inside the enclosure.
Line up the servo horn with the center of the bat. This means your servo will look like it's really off-center, but the part that matters is the bit that turns, so make sure that's as centered as you can get it.
Use a lot of hot glue to secure the servo to the outside of the wing piece. Align it "sideways" as shown, so the servo horn moves up and down.
Use more hot glue to secure the wing piece to the front piece along the edge of the cardboard rectangle. The HalloWing assembly should be facing front, with the screen inside the window, and the servo will be on the back of the bat (not between the pieces).
It helps to give a little crease where the wings connect to the body to allow lots of motion.
Thread the ends of the wires through the small holes in the wings. If you cut by hand, you may have missed these holes! That's ok, you can make them now. Exact placement isn't crucial. Use your knife or an awl to cut little holes in the wings and poke the wires through as shown.
You may need to loosen the screw and adjust the placement of the servo horn so it moves up and down like a light switch without hitting the bat body. Once you've got the alignment right, tighten the screw.
Use a paint pen, glitter glue, jewels, pipe cleaners, or anything you fancy to decorate your bat.
Tie a piece of string or fishing line around the head piece. I found that poking one end through the on/off switch hole helped me adjust the angle of the hang to get it just right.
Plug in a USB cable through your USB slot and thread it up along your string. The conductive thread trigger will not work as well if you unplug the cable completely -- even if the other end isn't plugged into anything at all.
Why is this?
The capacitive touch pad on the Hallowing is looking for a difference in resistance. When you touch the thread, your body makes a slight electrical connection to the wire, which the HalloWing can read. The HalloWing compares this value to a non-touched value, and if there's enough of a difference, it knows to trigger the servo.
If the bat is hanging in mid-air, there is no physical connection to the ground, so the HalloWing can't get a good baseline reading. Keeping the USB cable plugged in adds about a meter of wire to act as a ground connection. So even if the cable is not plugged into an outlet, that extra meter of wire makes all the difference in getting the capacitive touch pad to work.
Capacitive touch works better when there's a little more ground wire involved in the project. The wires inside the USB cable will help ground the bat so there's more of a change when you touch the thread -- even if the other end of the cable is not plugged into anything at all.
Enjoy scaring all the trick-or-treaters this Halloween!
