Touch sensor

This touch sensor is made from nanoparticles of gold and cadmium sulfide. 

Tactile touching sensors allow simple information from the environment to be recorded by touching the objects directly. In the simplest case, the sensor is a switch that sends a binary signal when set or not set. A variety of miniaturized switches are combined with line and matrix arrangements with integrated sensor data preprocessing to enable the creation of a tactile pattern recognition similar to the human sense of touch. 

The answer to this question apparently comes from the sensitivity of the receptors themselves. Each receptor has a broad range of sensitivity, being most sensitive to one particular input value and less sensitive to other input values, with the degree of sensitivity becoming smaller as the difference from the most sensitive input value becomes greater. With several of these receptors, each with a different maximum sensitivity, perception can be related to the combination of outputs from different receptors. Thus, we may see different colors that do not correspond to the maximum sensitivities of any of the color receptors. Tactile localization could occur as long as the output frequencies of the skin touch sensors vary with distance from the receptor loeation. 

A representative instrument [Kondraske et al., 1984 Kondraske, 1990] is illustrated in Figure 78.4. This device incorporates 8 LEDs and 15 high-speed touch sensors ( home, A1-A8 and B1-B6) and a dedicated internal microprocessor to measure an array of different performance capacities associated with information-processing. Measures at the most basic hierarchical level (visual information-processing speed, visual-spatial memory capacity, visual attention span, etc.) and intermediate level (coordination tasks involving different sets of more basic functional units) are included. 

FIGURE 78.4 Major components of a specific microprocessor-based instrument (Human Performance Measurement, Inc. Model BEP I) for measurement of a selected subset of information-processing capacities incorporating high-intensity LEDs for visual stimuli and large contact area, fast touch sensors to acquire responses (made by the upper extremity) from the subject under test (semicircle radius is 15 cm). 

The controller coordinates the transition between these positions and ensures that trajectories do not tangle. Feedback to the controller is provided by several devices. Potentiometers detect the angles of flexion of the digits touch sensors detect pressure on the palmer surfaces of the digits and a combined contact force (Hall effect) and slip sensor (from acoustic frequency output of force sensor) is mounted at... 

The Lego Mindstorms NXT robotic kit combines LEGO TECHNIC elements with ultrasonic, sound, light, and touch sensors (Figure 17-3). This combination allows you to make an intuitive robot. The light sensors can detect both color and intensity of light. The sound sensor allows the robot to respond to sound patterns and tones. 

This is an important human sense because it helps to relieve the load on both ears and eyes by conveying messages to the human brain. One example of this sense is that an individual can recognize different control knobs shapes simply by touching. The touch sensor has been used for many centuries by craft workers to detect surface irregularities and roughness in their work. 

In future sensor assemblies should already be constructed by an additional integrated optical sensor, so that the method works without contact. The probe has always a slight distance from the object in this case. Currently it is guaranteed through an integrated pressure sensor that acts in this case as a touch sensor, that the sensor rests on the surface. 

S. Takamatsu, T. Yamashita, T. Murakami, et al.. Weaving of fabric for meter-scale floor touch sensors using automatic looming machine. Sens. Mater. 26 (8) (2014) 559—570. 

We can easily implement a proximity sensor for the robot with a combination of ultrasonic sensors and touch sensors provided by the latest LEGO Mindstorms. A communication device for the robot can be also implemented with a bluetooth device built... 

Knitting electrically conductive fibres can introduce some highly sophisticated functionality. For example, a paper by Tennant et al. (2012) describes methods for producing frequency-selective surfaces at microwave wavelengths. This was achieved using silver-coated nylon yam on a polyester base. Alternatively, knitted conductive yams can be used to create touch sensor switches (Wijesiriwardana et al., 2005) or knitted strain sensors for stroke rehabilitation (Preece et al., 2011). 

PLLA films, with a larger shear piezoelectric constant than the oflier polymers in Table I and non-pyroelectricity, are greatly anticipated to be used as sensors and actuators for realizing unconventional HMIs because of their excellent fiexibility and transparency. A PLLA sensor has been combined with a projected capacitive touch panel to realize a deformation-sensitive touch panel (Ando et al. 2012). The touch sensor comprises a PLLA film, and the electrode of tiie touch sensor has a diamond stracture. A polycarbonate (PC) plate is used as tiie surface plate of the touch panel. The electrode consists of three layers, as shown in Fig. 9 (Ando et al. 2013). On layer 1, an RX electrode was... 

The above FTIRandSEM studies gave us some indication about the crystallization of PVDF in the fi-phase with the addition of CaClj and MWCNT, and in the following section we will focus more on the suitability of using the PVDF-CaCl2 and PVDF-MWCNT as a touch sensor in smart textiles. 

Touch Sensor Based on a PVDF Electrospun Web with CaClj and CNTs [20]... 

A flexible touch sensor was produced based on a PVDF web with CaClj and CNTs, as described in Section 8.3.2. A schematic representation of the sample set-up... 

Figure 8.19 Schematic representation of the set-up used to measure the piezoelectric behavior of the samples used in this study (a) touch sensor set-up and (b) instrumentation...

Figure 8.20 Output voltage (V ) measured after dropping the bead from varying height (20 and 30 cm) on the PVDF-based nanoweb touch sensor as a function of varying concentrations of (a) CaClj, (b) MWCNT, and (c) MWCNT-PCaCI (0.5 wt%).

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