Maker guide · Prices checked 7 November 2026
How to build a touch-sensitive fabric sleeve
The short version: cut touch pads from conductive fabric, sew each one to its own channel on a capacitive touch board with conductive thread, and read the board from a microcontroller. A Bela Trill Craft board ($19) has 30 touch channels. A 20 cm square of woven conductive fabric costs $4.95. That is about $25 in touch parts, plus a microcontroller you may already own.1,2
This builds the touch half of a garment GUI. It has no screen. Fabric displays like the NUS sleeve are still lab-only.
Parts list
| Part | Why | Price (checked 7 Nov 2026) |
|---|---|---|
| Bela Trill Craft | 30 capacitive touch channels on pins. Works with "anything conductive", including fabric.3 | $19.001 |
| Adafruit woven conductive fabric, 20 cm square | The touch pads. Under 1 ohm per foot across the fabric.2 | $4.952 |
| Conductive thread | Carries each pad's signal to the board. | See the parts page |
| Arduino-compatible board with I2C | Reads the Trill Craft. Trill works with Arduino, Teensy, Raspberry Pi and Bela.3 | Use one you have |
| A long-sleeve top, needle, scissors, iron-on interfacing | The garment and the tools. | — |
Step 1: Plan the pads
Put on the top and mark a row of pads along the outside of the forearm, where your other hand lands naturally. Four to six pads is a good first build. Mark a spot near the wrist or elbow for the board and battery, somewhere you can unclip them.
Step 2: Cut and fix the pads
Cut each pad about 2–3 cm across. Bigger pads are easier to hit. Back them with iron-on interfacing, then iron or stitch them onto the sleeve. Leave a clear gap between pads so a finger does not bridge two at once.
Step 3: Sew one line per pad
Sew a separate line of conductive thread from each pad to the board's location. Each pad needs its own line and its own channel on the Trill Craft, which breaks its 30 channels out to pins along each side.3 Lines must never touch each other. Where they cross, sew one on the inside of the fabric, or cover it with a strip of fabric glue or tape.
Step 4: Connect the board
Trill sensors talk over I2C.3 Connect the Trill Craft's I2C pins (SDA and SCL), power and ground to your microcontroller. The Trill Craft ships with an unsoldered right-angle header for these pins.3 Tie each sewn line to its channel pin with a small crimp, a snap fastener or a soldered wire.
Step 5: Load the example code
- Install the Trill Arduino library from Bela.
- Open its
craft-printexample. It is one of the examples that ship with the library.4 - Upload it and open the serial monitor. Touch each pad and watch its channel's number rise.
Each channel reads 12-bit values (0–4096) by default. Bela's settings guide explains how to tune sensitivity if fabric pads read too weakly.3 The library also has a craft-settings example for this.4
Step 6: Turn touches into actions
Pick a threshold for each channel, a bit above its untouched reading. When a reading crosses it, do something: light an LED, play a sound, or send a keypress. Boards with Bluetooth can pass that keypress to a phone. Check your board's own documentation for how.
A touch also gives a size, not just on or off. Trill estimates touch size from how many channels change and by how much. A light fingertip touches less area than a firm press, so size works roughly like pressure.3
Washing and care
- Unclip all electronics first. Only the fabric pads and thread stay in the sleeve.
- Adafruit recommends dry cleaning for its woven conductive fabric and notes it can discolour over time.2
- For something truly washable, you are into professional territory. Even Loomia's e-textile samples are not washable unless made with a different process.5
Safety
- Use a low-voltage, protected battery pack, and keep it removable.
- Never wear it while charging.
- Keep bare thread lines from touching skin for long periods if they rub or irritate.
FAQ
- Is this a garment GUI?
- Half of one. It senses touch but has no screen. The NUS garment GUI adds pixel fibres that display images.6
- Can I use copper tape instead of fabric?
- Yes. Bela lists copper tape, metal and wire alongside conductive fabric as materials that work with Trill Craft.3 Fabric is softer to wear.
- How many pads can I have?
- Up to 30 per Trill Craft. Several boards can be chained for hundreds of channels.3
Sources
- Bela shop, Trill sensors, checked 7 Nov 2026. shop.bela.io/collections/trill
- Adafruit, Woven Conductive Fabric 20 cm square (product 1168), checked 7 Nov 2026. adafruit.com/product/1168
- Bela Knowledge Base, "About Trill". learn.bela.io/products/trill/about-trill
- BelaPlatform/Trill-Arduino, examples folder, checked 7 Nov 2026. github.com/BelaPlatform/Trill-Arduino
- Loomia, Kits and samples, checked 7 Nov 2026. loomia.com/samples/kits
- NUS News, 22 Oct 2026. news.nus.edu.sg/worlds-first-touchscreen-in-garment