TacTex: A Textile Interface with Seamlessly-Integrated Electrodes for High-Resolution Electrotactile Stimulation

We developed a fabric that works as a tactile display: it renders patterns you can feel directly on the skin and senses where you touch it. The display is electrotactile: tiny pulses stimulate the touch receptors under the skin, so soft cloth produces rich, controllable sensations.

Dense electrode grids normally fight fabric, so prior interfaces attached patches on afterwards. TacTex weaves the electrodes into the cloth in a single run on a standard loom: the finished textile is already a display and still feels like everyday fabric.

The textile. A dense woven electrode array giving both stimulation and touch tracking at 512×512 resolution, from linear electrodes spaced as closely as 2 mm.
The driving system. Spatial and temporal control of the stimuli while simultaneously monitoring voltage, so touch tracking never disturbs the haptics.
The vocabulary. Four sensation qualities, ten static and ten dynamic patterns, all distinguishable in user evaluations.

Creating touch with electricity

Soft cloth renders patterns you can feel by stimulating receptors under the skin, with nothing physically moving.

A diagram of a cross section of the skin, titled a tactile pixel on the electrotactile display. Two electrodes are shown labeled with plus and minus correspondingly. An arrow pointing from plus electrode goes to the minus electrode. The arrow is labeled with a lightning icon and the word pulse current. The arrow intersects with a drawing of a tactile receptor, with more receptors drawn nearby. — Each “tactile pixel” on the display consists of a pair of electrodes; in TacTex, these are two conductive yarns in the weave. Whenever the pixel is supposed to be felt, our system passes tiny current pulses between the electrodes, which stimulate the tactile receptors under the skin, causing a sense of slight touch, with nothing physically moving.

A close-up of the woven textile with a fingertip touching it. Overlaid red and blue lines run through the weave, tracing the conductive yarns that form patterns on the fabric. — Activating several pixels together draws a **static pattern**, such as a thin vertical line; shifting the active pixels over time draws a **dynamic pattern**, such as a line sweeping across the palm. Changing the pulses themselves changes the **quality** of the sensation: pricking, caressing, tapping, or pressing.

Implementation

Three parts make this work: the woven textile that carries the electrodes, the circuit that drives and reads them, and the connection between fabric and electronics.

The weave structure. Top left: a 3D diagram of the multi-layer weave unit with labelled warp and weft yarns. Below: variants showing how yarn counts set electrode size and spacing. Right: a photograph of the woven fabric with a 1 cm scale bar and a rendering of the weave overlaid. — **Textile design.** Conductive yarns run lengthwise and crosswise through a multi-layer weave, and non-conductive yarns sit between them so the two directions never short-circuit inside the fabric, while both stay exposed on the side that meets the skin. That shared electrode grid drives both **electrotactile stimulation** and **capacitive touch sensing**. Electrode width and spacing are set simply by yarn counts, down to **2 mm**. The same structure also supports double-sided displays, insulated backs, and decorative colours.

The driving board: a green circuit board with a microcontroller, a 200 volt input and two 200 volt outputs, data and power connectors, and rows of sockets that route stimulation and sensing to the textile's electrodes. — **Driving circuit.** A custom stack of power, switch, and sensing boards selects which pixel receives pulses at each moment. Each pulse is very short, so the boards can cycle through many pixels fast enough that separate spots feel simultaneous. In the gaps between pulses, the same boards **measure the voltage on the yarns to detect where a finger is resting**. This is how stimulation and touch sensing share one surface.

The fabric-to-board connection. Top left: a diagram of edge electrodes bonding to pitch-matched pads. Bottom left: a close-up of the flexible printed connector with fanned-out golden traces. Right: a heat press clamping the connector onto the woven textile. — **Connection.** Fabric cannot be soldered, so the electrode yarns at the edge of the textile are clamped against a **flexible printed connector** with a conductive adhesive, giving each yarn its own clean channel to the driving board. Because the electrodes are continuous lines across the cloth rather than individual pads, a 512×512-point display only needs 512 + 512 connections instead of one per point.

User study

We evaluated whether people can actually read the display: tell the sensation qualities apart, and recognise the static and dynamic patterns.

The stimulus set. Top: photographs of four sensation qualities delivered to a fingertip. Below: grids showing static patterns, such as single vertical or horizontal lines, and dynamic patterns rendered as sequences of bars sweeping across the array. — **What we render.** The display produces **four sensation qualities** (pricking, caressing, tapping, and pressing) plus **ten static patterns**, such as a thin vertical line, and **ten dynamic patterns**, such as a line sweeping across the fabric.

The study setup: a participant rests their hand on the electrode board, connected by a ribbon cable to the drive stack and a laptop showing a practice trial; an inset shows a fingertip touching the woven textile. — **Study protocol.** Participants felt each stimulus on the textile without seeing it, then **identified** which quality or pattern it was and judged whether pairs of sensations were the same or different.

Two stimulus-perception matrices, one for static patterns and one for dynamic patterns. Each is a ten by ten grid where rows are the pattern presented and columns the pattern reported. Bright cells run along the diagonal, showing that the pattern participants reported was usually the one presented. — **What we found.** Rows are the pattern presented, columns the pattern reported. The **bright diagonal** means responses mostly landed on the pattern actually rendered; the off-diagonal cells cluster among adjacent lines, which is what sets the practical resolution of the display.

Team

This is a collaboration between the Institute of Software (Chinese Academy of Sciences), Zhejiang University, and Hangzhou City University by:

Together with Shengsheng Jiang, Qi Wang, Wei Sun, and Feng Tian.

Publication

This work is published at ACM CHI 2024 (see paper via DOI). Authors’ print is available here (PDF).

Lin, H., Liu, X., Jiang, S., Wang, Q., Tao, Y., Wang, G., Sun, W., Han, T., & Tian, F. (2024). TacTex: A Textile Interface with Seamlessly-Integrated Electrodes for High-Resolution Electrotactile Stimulation. In Proceedings of the CHI Conference on Human Factors in Computing Systems (CHI ’24). https://doi.org/10.1145/3613904.3642873

@inproceedings{lin2024tactex,
  title={TacTex: A Textile Interface with Seamlessly-Integrated Electrodes for High-Resolution Electrotactile Stimulation},
  author={Lin, Hongnan and Liu, Xuanyou and Jiang, Shengsheng and Wang, Qi and Tao, Ye and Wang, Guanyun and Sun, Wei and Han, Teng and Tian, Feng},
  booktitle={Proceedings of the 2024 CHI Conference on Human Factors in Computing Systems},
  year={2024},
  doi={10.1145/3613904.3642873}
}

Overview

Creating touch with electricity

Implementation

User study

Team

Publication