PowerHeat NT Seat Heating & Customer Sensing Solution
Free-form shaping of the heated textiles (curvilinear, rectilinear, and cut-outs are possible) while maintaining the same power density & the same temperature. Design flexibility is made possible by the patented integration of the conductive components into the fabric. The innovative heat-transferring fabrics consist of an exceptional thin heating fabric structure. This structure would enable a 3D laminated composite that will quickly and uniformly heat without hot spots or surface marking. In addition, exceptionally fine heating fabric structures allow, for example, a thin, hard 3D lamination without marking on the surface with an unrivaled value appearance.
SEFAR® PowerHeat NT is a durable and safe heating solution. It will continue to function, even if damaged.
Potential applications Automotive interieur heating, belt, armrest, Heavy vehicles – truck deicing, floor heating in buses, trains, and campers, home appliances – beds, furniture, slow cooker, mirror cabinets, Medical – operating room table, neonatal incubators, and Clothing – jackets, trousers, shoes.
Other advantages are soft & hard lamination, thermoforming, injection molding, back foaming, and sewing. The PowerHeat heating fabric is flexible, efficient, and can be integrated into most production processes and brings you versatile benefits (refer to https://www.sefar.us/).
- Highest energy efficiency
- Light and thin
- 3D moldable
- Safe – no hotspots
- Robust
- Process integration: injection, foaming, laminating, gluing in
- Free shaping and any cutting to size
- Various voltage and power ranges (up to 50V AC / 120V DC and up to 2000W/m²)
- Very fast heating time
- First-class value appeal
- Translucent
- Isolated as required.
- High air permeability
- Partly self-regulating thanks to PTC characteristics.
The added opportunity with Smart-Surface is to integrate a cheap, unobtrusive textile pressure sensing matrix that allows the acquisition of surface pressure distribution patterns with large temporal and spatial resolution and high dynamic sensing. (Refer to Smart-surface: Large-scale textile pressure sensors arrays for activity recognition).
Resistive pressure sensors or resistive force sensors recognize occupants through the force on an area. Pressure sensor-equipped chairs/seats can detect a user’s posture or a driver’s identity. Printed polymer-film pressure matrices are cheap in price and available on the market, but with very limited flexibility and no air permeability.
A simple pressure-sensitive element can be built by placing a pressure-sensitive layer, e.g. carbon polymer foam between two electrodes. When force is applied to the sensor, the conductive layer gets compressed and the density of the conductive particles in the material increases, causing the resistance to drop. The resistive change is relative to the force applied to it and can be converted to a voltage by a resistive voltage divider. The voltage signal can then be digitized by an analog-to-digital converter (ADC).
When multiple pressure sensors are arranged into a matrix, a greyscale image is created, representing the pressure distribution over the matrix. When touched by a person, the sensor matrix not only captures the overall force/weight but also reveals detailed information like the shape and size of the contact area. With the low-noise analog design, high precision 24-bit ADCs, and appropriate sampling rate, the matrix can produce a pressure image stream containing a lot of details about the person’s activities.
Smart-Car Seat for monitoring the driver’s activity as it may be important for them to be aware 
of the driver’s mental as well as physical status. A pressure matrix built into the seat can measure how the driver sits and moves, which might be linked to uneasiness, discomfort, or stress. Such postures and actions could even be used to predict traffic context and the driver’s intentions. Dangerous maneuvers such as reaching into the back seat or to the car floor (e.g., to take care of a child or to pick up a dropped mobile phone) could also be detected. Thus, pressure patterns that result from direct contact with the relevant body part but are not generated by the user specifically for interaction with the system can be analyzed to detect driver or passenger activity.
Sefar provides a mass-producible generic fabric for sensors that allow the measurement of various activities of human bodies by capacitive, resistive, and/or bioimpedance modes. The resting sensing mode represents the pressure-resistive sensor. The sensor consists of two fabrics with an array of metallic conductive parallel stripes as electrodes and a third fabric as a semi-conductive intermediate layer. As the sensor area is pressed, the resistance decreases. The resistance-pressure relationship is predictable and repeatable and resistance is insensitive to other physical variables. The fabric pressure sensor shows sensor function properties having by far the most sensitive structure in the response.
