the final piece, a square piece of muslin with a laser engraved logo on it

I wanted to create a piece which would respond to my touch. I love muslin and the way it feels. It's soft, yet has a rough tactile quality which makes it nice and warm to hold. I wonder what muslin feels like when it is touched. Does it like being held? Does it be held firmly or caressed softly?

In an attempt to answer this question, I created a piece made of muslin which actively responds to being interacted with.

the same image, but with a grid of 8 leds below the muslin lit up

close up on the logo with leds lit up

illustration of different layers of the sensor
The piece is split into individual layers–sensor, reactor, and the cover.

The sensor is a 6x6 pressure sensitive sensor, which uses a grid of copper thread and velostat to work. Heavily inspired (read: copied) from Kobakant, it can detect where pressure is applied on a 2D X-Y area. The velostat can help detect the intensity of pressure as well. With a 6x6 sensor, it has 36 individual 'sensors'.

I wanted to hand sew everything as it felt like the right thing to do with muslin. The material feels analogue and machine sewing wouldn't feel appropriate. However, I did want to sew well, which meant good spacing, and straight lines. The laser etched guides allowed me to do just that. I cut and etched three pieces of muslin, 2 for the sensor, and 1 for the SMD LEDs.

By detecting pressure applied to sensor, and how many points are being pressed, I can somewhat determine the way the piece is being touched or interacted with. If only a few points are being touched with lots of pressure, the piece is being poked. If many points are being touched softly, then I can determine that my palm is on the surface. With 36 individual sensor points, the sensor is of a fairly high fidelity and does a good job of determining the kind of touch being applied.

Visualisation how the piece detects touches

Laser etch at the center of the sensor

I didn't want the piece to be tight or tense, so I used four cross stitches to attach the outer layers to the inner sandwich. It also kept the micro-controller and coin cell battery holder easily accessible incase I needed to make some changes.

Cross-stitched the outer layers

Easy to replace coin cell battery

Can be plugged in to change software or make plug in additional hardware