Victorian Ball Gown With an Autonomic Adjustable Neckline

This is a project I made for the Victorian Winter Ball in Cracow. A smart ball gown which adjusts the size of its neckline based on the proximity of a gentlemen standing in front of it.

• Particle Photon microcontroller
• Feetech FS90R micro servo
• US-015 ultrasound proximity sensor
• jewlery string
• thread bobbin (from the sewing machine)

Some time ago I read a story behind the fameous painting "Portrait of Madame X" by John Singer Sargent. Back when it was first displayed the black dress caused a public outrage. The neckline of it was deemed so scandalous that it tarnished the reputation of a young lady who modeled for it and almost put an end to Sargent's career. I wondered how different would their lives go, if the indecent attire itself knew it was not appropriate.

Luckily in the age of wearable technology such things are possible! So under the discuise of a mad steampunk inventor I decided to create a smart gown that automatically protects the modesty of the wearer, providing that temptress-from-a-far but prude-up-close look that every Victorian lady dreamed about.

This could be its own instructable, but for the purpouse of focusing on the tech part of this project I'll try to narrow it down to one step.

I'm a historical reconstructor so my usual hobby is sewing historical costumes. The fashion of this dress is called Natural Form and comes from a very short but beautiful period of 1877-1882. It was in those magical five years when the european fashion designers took a break from the extravagant bustles, narrowed down the shape of the skirt and focused most of the decorations and draperies below the knees on long trains.

I made all of the elements and underpinnings myself, excluding only the corset, which i had ready made. The full dress with the trimmings took 5m of green tafeta fabric and not much less white cotton for the frilled petticoat which provided most of the shape. To get the fan-tail skirt and panier overskirt fashion right I followed the TV225 and TV328 patterns from Truly Victorian.

Some of the trimmings - like the frilled black ribbon - were machine made (in 1880s that's already historically appropriate) but some I still made manually, pleat by pleat.

More info about the sewing part is on my historical blog Cavine Sartorium.

The geeky part started with the last element of the outfit: a separate fitted bodice, with a loosely draped neckline.

I threaded a jewlery line inside the draping and lead it from one shoulder to another. This is what’s responsible for the folding. If the line is long - the neckline lies loose. If the line is short - the neckline tightens to a more decent size.

The length of the line is controlled by a small motor. One end of the line is winded on a thread bobbin - like the ones you use in a sewing machine. The bobbin is attached to a servo motor. I used Feetech FS90R micro servo for continuous rotation (360 deg) because the bobbin needed to be winded many times to make a difference. The whole mechanism is hidden iside the drapings and attached over the right shoulder by a black ribbon. I used another empty bobbin to be able to catch it with a ribbon. And a lot of hot glue to make it stable.

The second crucial element is the US-015 proximity sensor, attached at the center of the bodice and pretending to be just an awkward frilled brooch. The sensor works like a sonar in 2-400cm range. It emits an ultrasonic chirp from one 'eye', and with the other it listenes for the echo of this chirp to come back. The time that it takes for the soundwave to come back is relative to the distance of the obstacle it was reflected against. In our case this would be our our inappropriately forward gentlemen.

We can thus calculate the distance of the gentleman from the equasion:

gd = ttr × c / 2

where

gd - gentlement distance
ttr - time till the soundwave returns
c - velocity of sound (340m/s)

As "inappropriate" I set the distance of 80cm.

The element connecting the sensor and the motor is the microcontroller. In here I used Particle Photon, which I just can’t stop praising. Other than its much more discreet size it also has better ease of development then Arduino. Photon comes already equipped with a WiFi module (yes, the gown is technically connected to the Internet :D), which it uses to flash the code through the very convenient Particle online IDE. What it means for me, is that I can change the program without ripping the device from the sleeve to physicaly connect to it each time I want to make a change. I can even make last-minute code adjustments from my phone.

Photon also comes with a few pins that can handle PWM signals, so no additional controller for the servos was needed. It even provides a ready library for controlling servos.

As for the distance measurment: US-015 is a digital sensor, which means it can only process binary input and output: 5V is high, 0V is low. To emit the chirp soundwave it needs to be activated by recieving a high state to one of its pins. It then immediately sets a high state to the second pin and keeps it high until the soundwave comes back. Which means that our ttr from the previous equasion is simply the time the high state was kept up.

This is how all the elements are connected.

All the cabling is hidden inside the neckline drapings. The whole system is powered by an usb powerbank that's placed securely inside a petticoat pocket on the hip.

All that was left to be done, was writing the logic to controll the motor. Since winding and unwinding of the line took some time I needed to design a state machine that would recognize if the neckline is already high enough and wouldn’t try to wind it more. Initial bugs in this condition, resulted in the dress trying to strangle me a few times. It is equipped with WiFi, but apparently not with Asimov’s laws...

It also needed to react to the changing situation and stop winding up if the gentlement took a hint and moved back while the neckline was operating.

The whole code needed for transitioning between the states and operating the neckline is here

Here are a couple of conclusions after spending the entire ball in this gown:

– Did it succeed in protecting my reputation?

If generating disproportionate attention to my cleavage and making it a topic widely discussed could be called protecting a reputation, then yes… It certainly gave me a reputation of a local weirdo.

– Did it prove practical at the ball?

A set of vigorous english country dances, and covering myself with unprotected and undertested electronics – what could have went wrong? YOLO-driven development and unstable pin connections resulted in me fixing the device more often then I was using it.

– Was it worth it?

Oh yes