Hello my name is Olivia Ruston and I will be presenting the work, 'More than it Seams
: Garment Stitching in Wearable e-Textiles'
This work was completed together with my co-authors Leon Watts and Mike Fraser.
Before we get into it, I'm going to ask you to take a moment to get comfortable. Sit back
in your chair or maybe adjust your stance - stretch out your arms, straighten your back.
Think about how your clothes feel on your body. If you're wearing a shirt, you might
feel the fabric straining against your movements. If you're wearing a jumper, the knitted material
might stretch with your body.
All clothing is worn on and moves with the body but different clothes are intended for
different uses which impacts how they are designed and constructed.
I'm going to talk about seams in clothing and how they can be designed for interactive
sensing of body movement.
In our work we have produced bodice garments in which seams are constructed using conductive
yarn. The conductive yarn seams are activated at low voltages which fluctuate as body movement
varies tension across the seams.
We explore how garment blocks, seams and stitches provide a traditional language for clothing
design which can be repurposed, and ultimately reconsidered, in the emerging opportunities
that clothing provides as the user interface.
Through our work, we demonstrate that passing low voltage through seams sewn from conductive
yarn enables identification of body movement.
We carried out investigations that compare stitches to identify the best balance of seam
conductivity against robustness under repeated stretching. Zigzag stitching provides an excellent
balance, but that recalibration between stretches is still necessary.
We evaluated garment designs by looking for differences in resistance across different
seams under the influence of torso movement. Focusing on the effects of construction, we
found that seam number and seam placement benefit the discrimination of body movement.
Our work is grounded in an understanding of fashion design and construction processes,
in order to find ways exploit them for fabrication of wearable e-textiles whilst maintaining
existing practices.
We focus on seams and their wider role in garment construction. Seams refer to the line
of stitching which join together two pieces of fabric. In garments, seams provide structure,
taking flat fabrics and creating something that fits the body.
There are a number of steps in creating a finished garment. I find it easiest to understand
them by working back through the process.
Before you have a finished garment, you must go through the pattern stage. Activities in
this stage are inform the construction. A pattern is a set of templates and instructions
which describe the shape of the fabric pieces and how they should be sewn together.
A pattern is developed from a design sketch using a garment block. A block defines the
dimensions for a basic garment form. Block sets vary but typically they include a bodice,
skirt, sleeve and trousers. They can be combined and adapted to make clothing of all different
styles and shapes.
Block enables a bespoke pattern which is used to produce the finished garment.
In exploratory design work, we produced a sleeveless bodice using a garment block. It
was sewn on a domestic sewing machine using conductive yarn.
Conductive yarn is a resistive material. In this case, it is made from 20% Stainless Steel
and 80% Polyester. It's intended for stretch and pressure sensing - tension increases mechanical
connections between the stainless steel threads, resulting in reduced electrical resistance.
The first prototype was made in an undyed calico. A cheap material, typically used when
drafting new garments.
A subsequent prototype was made using blue-coloured jersey. This material is often used in clothing
and you will recognise it as the material t-shirts are made from.
An Adafruit Flora board was sewn to garments and connected to the side seams. Metal snap
fasteners were sewn at either end of the seam and the corresponding fastener was attached
to a wire which was attached to the Flora board.
Early testing with the bodice involved repeating a sequence of movements and recording the
voltage values measure.
The board was connected to a computer via USB, providing both power and serial communication.
Voltage signals measured and then logged in a csv file.
At points in the movement, the signal from the side seam suggested some relationship
between movement, seam manipulation and voltage.
We carried out a series of investigations into the robustness and behaviour of conductive
yarn.
Firstly we assessed the viability of the material by measuring how resistance varies through
the conductive yarn. Our findings indicated that there are some breaks in conductivity
in the yarn.
Subsequently, we investigated how different stitch types effect overall conductivity and
mitigation for material faults.
We tested two stitch types, zigzag and plain stitch, with varying dimension making a total
of 5 variations.
The initial resistance of each sample was measured, and then the sample was stretched
to the limit of the fabric and the resistance measured again. In some instances, it was
not possible to record a reading for resistance and this was labelled as a failure.
The DoubleZZ 1.5x1.5 stitch did not fail in any sample before or after stretching. We
concluded this to be the most robust stitch type from the variations tested.
The final investigation considered 'wear and tear' on the seam. The average resistance
across the samples decreased after repeated stretching which suggests that manipulation
caused the base level resistance to changed.
Therefore in our main experiment movements are calculated from signal deviations from
resting values.
In the main study we compared two designs, focusing on different seam placements and
number of seams.
Two designs were produced. They were based on the original prototypes and made from pink-coloured
jersey:
The first was made from two pieces of fabric and used two vertical seams under the arm
- as seen in t-shirts The second was made from six panels of fabrics
with two additional pairs of seams added to the front and back, making a total of six
seams
We evaluated garment designs by looking for differences in resistance across different
seams under the influence of torso movement.
A single experimenter wearing the garment performed three defined movements.
The movements were designed to increasingly focus movement around the torso, with Movement
1 having the least torso movement and Movement 3 having the most.
We took inspiration from yoga - as practise that has a defined set of variable movements
this provided a structured approach to experimentation.
It is also possible to define beginning and end points of yoga movements, making it suitable
for the necessary calibration.
There were 4 main findings from our main study. Due to time I'm only going to pick out one
but please look at the paper for more.
For the torso and the forms of movement we have been exploring, the most significant
voltage changes were seen in the back seams and the least in the front.
This makes sense when you think about how we move, we don't typically invert our back
in everyday life which would stretch the front seams. However, the front seams do contribute
to the fit of the garment to body - perhaps further explaining an improved performance
of garment two over garment one.
There is a balance to strike between sensing capabilities and the mechanical responsibilities
of seams. The images on screen show stays, historical support garments, and a professional
surfer wearing a wetsuit designed to accommodate paddling through water.
We can look to historical garments and specialised sportswear for possible seam placements.
Finally, I will reiterate the key contributions from this work.
We demonstrate that passing low voltage through seams sewn from conductive yarn enables identification
of body movement.
Through a comparison of stitch types, we identify that double zigzag provides the best balance
of seam conductivity against robustness under repeated, but that recalibration between stretches
is still necessary.
We evaluated garment designs, focusing on the effects of construction, with findings
indicating that seam number and seam placement enhance discrimination of movement.
If you would like to find out more please read our paper.