Embroidered Textile Pressure Sensor Could Give Protective Clothing a Sense of Touch

Researchers at Riga Technical University, working with a colleague at the University of Minho, have built an ultra-thin pressure sensor made almost entirely from fabric. Described in Frontiers in Sensors, the device is a single textile layer with rows of conductive electrodes embroidered onto both sides, forming a matrix that can register where pressure lands on its surface and how hard the impact is. Because the sensor uses only textile-based materials, it keeps the drape and feel of ordinary cloth, which is exactly what smart protective clothing needs if it is to be worn comfortably for hours.

The team’s motivation comes from a familiar problem in wearable sensing. Most fabric pressure arrays are sandwiches: a piezo-resistive layer sits between two outer conductive layers with parallel electrode tracks. Such multilayer stacks work, and they have powered smart beds, posture-monitoring cushions and exercise mats, but they are thicker, stiffer and harder to integrate into garments. The novelty here is that the pressure-sensitive fabric itself carries electrodes on both faces, so a single layer does the job of three. Fewer layers mean a thinner, more flexible sensor that can be sewn into fencing jackets, soft body armor or industrial workwear without changing how the clothing moves.

The researchers drew on their earlier surveys of commercially available piezo-resistive textiles, which had shown that polyester knits with a piezo-resistive polymer coating and carbon-loaded polyester wovens are the strongest candidates for pressure sensing. Two fabrics made the final cut. The first was Sefar Carbotex 03-205CF, a woven fabric from Sefar AG in which carbon-impregnated composite weft threads alternate with non-conductive polyester threads; it has a surface density of just 0.85 grams per square meter and a thickness of 225 micrometers, making it one of the thinnest piezo-resistive fabrics available. The second was EeonTex LTT-SLPA 60 kOhm from Eeonyx Corp., a bi-directionally stretchable knitted fabric of 72 percent nylon and 28 percent spandex coated with a conductive polymer formulation, with an area density of 163 grams per square meter and a thickness of 0.38 millimeters.

For the electrodes, the team turned to machine embroidery rather than printing. Printed conductive patterns on fabrics tend to fail under the bending and tensile deformation that protective clothing endures, whereas embroidered electrodes are literally stitched into the textile. The electrode design was drawn in the embroidery program Brother PE-DESIGN V8, using a snake-like pattern of three-step zig-zag stitches. The zig-zag geometry is not decorative: it places the conductive thread at a 45-degree angle to the warp and weft of the fabric, which prevents the thread from slipping between the yarns and creating a short circuit. Each sensor measures 6 by 4 electrode lines, with vertical lines 25 by 173 millimeters and horizontal lines 25 by 257 millimeters, fitting the largest available 300 by 200 millimeter embroidery frame and producing 66 crossing points where pressure can be localized.

Getting the embroidery right required some careful stitch-craft. The conductive thread chosen, Thermotech N-30 from Tibtech Innovations, is a non-insulated multifilament steel yarn with an electrical resistance of 30 ohms per meter, considerably better than the Madeira HC 12 thread used in the team’s earlier sensors, which measures under 100 ohms per meter. Because Thermotech N-30 cannot run through the needle, it was fed as the bobbin thread, so the seam tension had to be tuned so that the steel yarn lies in a clean line on the underside of the fabric without ever poking through to the surface, where it could short against the electrodes on the opposite face. Standard embroidery tensions of about 20 grams on the needle thread and 50 grams on the bobbin proved insufficient; raising the bobbin tension to 70 grams and the needle tension to 30 grams produced seams in which no conductive thread was visible on the fabric surface.

The two finished sensors were wired to a readout board built around a SAM D21 32-bit microcontroller, which samples resistance at roughly 80 kilohertz and carries a built-in impact-detection threshold. When an impact is detected, the data points immediately before and after the event are streamed to a computer over a serial port, which automatically aligns the records and simplifies analysis. Custom software written in Processing 4 displays the readings as a 4 by 6 matrix on screen. In demonstration tests, the matrix stayed flat at rest, and when a finger pressed the sensor, the corresponding square moved on the display, showing that both the location and the magnitude of the pressure could be read out in real time.

Quantitative testing was carried out on a Zwick/Roell Z2.5 compression and strain test column, with sensors pressed between polyimide plates under a 0.5-newton preload across three force ranges: 0.5 to 5 newtons, 0.5 to 50 newtons and 0.5 to 100 newtons, corresponding to pressure levels of roughly 15, 125 and 250 kilopascals. Resistance was logged with an Agilent A34970A ohmmeter, whose accuracy of 0.008 percent of reading plus 0.001 percent of range is negligible compared with the drift and hysteresis of the fabrics themselves. In total, 24 cyclic tests were performed, with each sensor probed at four points and cycled seven times per range.

The results split cleanly between the two fabrics. The Sefar Carbotex sensor showed poor load-cycling repeatability in the low range, improving in the middle and high ranges, but its behavior varied significantly from point to point, making it hard to summarize a typical range of load and resistance changes; its hysteresis values mostly fell between 0.44 and 0.94, and its sensitivity ranged from about 0.004 to 0.05 kilopascals. The EeonTex sensor was the clear winner, with better cycling repeatability across low, middle and high ranges, comparable values at different pressure points, hysteresis mostly between 0.83 and 0.94, and sensitivity in the range of 0.002 to 0.005 kilopascals. Intriguingly, the two fabrics respond in opposite directions: resistance falls with pressure for the Carbotex sensor but rises for the EeonTex sensor, which the researchers attribute to the elasticity of the knitted EeonTex structure.

The team concludes that the EeonTex-based sensor is the better candidate for smart textiles, offering good sensitivity and hysteresis comparable to their earlier three-layer designs, while the stiffer Carbotex fabric trades sensitivity for durability. Because the embroidery approach is compatible with industrial automated machines, and because tailored fiber placement technology could automate the wiring step that was done by hand in this prototype, the researchers argue that single-layer matrix sensors of this kind can be produced at scale. The sensor can also be resized or reconfigured with different numbers of vertical and horizontal electrodes depending on the application.

Potential uses stretch well beyond the lab. The authors point to fencing equipment, bullet impact detection in soft body armor, and protective clothing for people who work around moving machinery or falling objects, such as heavy agricultural machinery operators and first responders. A medical application is also on the list: mattress toppers that monitor body impressions. Compared with commercial printed-plastic injury-detection sensors costing more than 400 dollars and specialized pressure-mapping systems used in medical and sports products, an embroidered all-textile matrix offers a cheaper, softer route to clothing that can feel a blow, report where it struck, and say how hard it hit. Further work will focus on electrode configurations for specific applications and on calibration and repeatability studies of finished sensors.

Subject of Research: A single-layer embroidered textile matrix pressure sensor for smart protective clothing

Article Title: Thin single-layer textile-based matrix-type pressure sensor for protective clothing

Article References: Briedis, U., Vališevskis, A., Santa, B., & Carvalho, M. (2026). Thin single-layer textile-based matrix-type pressure sensor for protective clothing. Frontiers in Sensors, 7, Article 1800053. https://doi.org/10.3389/fsens.2026.1800053

Image Credits: AI Generated

DOI: 10.3389/fsens.2026.1800053

Keywords: smart textiles, pressure sensor, piezo-resistive fabric, embroidered electrodes, protective clothing, wearable technology, impact detection, machine embroidery, EeonTex, Sefar Carbotex, body armor, conductive thread