Etheric Waistcoat


A bit of steampunkery for Wye Waltz 2011.

I had a grand plan to make a waistcoat with animated glow, controlled by an accelerometer and an Arduino.

But I was too late and too lazy, so I just used always-on EL wire.

The wire came from eBay, a few quid for 7.5 feet of wire and a USB-powered inverter, all the way from China.

For reference, the SparkFun El Escudo is an arduino shield that'll run 8 outputs under software control. Proto-PIC and SK Pang carry it in the UK.

I wanted more channels, so my plan was to use a pair of 74HC595 shift registers in series driving 16 Z0405MF triacs (via a 1k resistor from 595 to the triac gate) to get a 16-channel device that only used a couple of Arduino pins. I actually got this breadboarded with a couple of triacs, driving the wire happily.

There's a helpful Arduino sample for driving the 595 which reduces the coding to trivia.

That was the smallest through-hole triac I could find, if you don't need through-hole the Z0103 might be a better choice. It is certainly smaller.

We start the actual construction with the Modern Tailor Outfitter and Clothier:


These are the instructions for constructing a general waistcoat pattern, starting from a few measurements of the intended wearer.

I followed the instructions to the letter, on a bit of pattern card, then cut it out. Then put those patterns on another bit of card and made a pattern with a seam allowance (15mm).

My waistcoat had three layers - decorative outer, decorative lining, and an middle layer of plain cotton which carried the EL wire (hot-glued on with a dab every couple of inches).I cut the middle layer first for fit testing.

Fit testing suggested that bigger armholes and neck would be more comfortable, so I trimmed the pattern and middle layer to suit.

Then cut out all the layers.

And sewed them together as three separate waistcoats (with the EL wire hotglued onto the middle layer). This was actually a mistake, as the topology required to turn a waistcoat inside out after sewing the edges require the lining side seams to be open. I had to undo some seams in the lining and do the shoulder seams in bits. Next time, I'll plan this part rather better.

Waistcoat pockets turn out to be easy when you work out the trick, but you do need to be precise for it to look good, and you need to sew a bit of outer to the pocket bag to avoid this white stripe.

The sequence (to remind me when I do this next) is:
Slit pocket in front, making Y cuts to the corners, to make four flaps
Cut out pocket and welt (both just folded rectangles).
Sew a patch of the outer fabric onto one end of the pocket. This will camouflage the top edge of the pocket if you don't get the alignment exactly right. You can see what happens if you skip this in the photo above.
On the outside of the waistcoat, sew folded welt and front of pocket to bottom flap. The stitch line must run exactly along the line between the bottom corners of the hole.
Push welt and pocket through the hole to the inside of the waistcoat.
Fold front along the top edge of the hole, sew back of pocket to top flap
Fold front along the side of the hole so that L side of pocket and the L end of the welt can be sewn to the L side of the front (the little triangular flap made by your original Y cuts)
And sew all the way down the L side of the pocket
Repeat for R side of pocket

Viewed from the inside:

Having sewn it all up and fitted buttons, I was amazed to find the thing fitted perfectly. Hurrah for science!

Inverters (one for each of the four strands of EL wire) and batteries go in a pocket.


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