Fig. 2: The working principle, output performance, and characteristics of temperature and humidity of the device.
From: Sensing of joint and spinal bending or stretching via a retractable and wearable badge reel
a A top view of the stretch sensor when rotating clockwise and anticlockwise, and the right side of the image indicates the detail of the device’s 3D structure. b Schematic diagram of the working mechanism of the stretch sensor based on freestanding triboelectric nanogenerators (TENG). c Potential simulation of one working cycle by FEA with 0.3-mm electrode width, and (d) the simulated results of the open-circuit voltage with different electrode widths 0.3, 0.5, 0.7, and 0.9 mm. e The basic electrical output characteristic diagram of the stretch sensor with 0.5-mm electrode widths. f Voltage signals with different velocities from 50 to 250 mm s−1 under a given displacement (36 mm) and g represents the theoretical and measured frequency corresponding to different velocities. h–i The output performance of the sensor at different environmental temperatures and humidity, and its corresponding displacement accuracy is shown in j. All error bars represent standard deviation based on ten replicate data under the same test condition. Source data are provided as a Source Data file.
