ALGRA Finger-Powered Wireless Piezo Switch being developed is being designed for stick-on light switch. The 
technology, dubbed Dynapic, is based on low-movement piezo keyboards that the company has been making for hygiene and vandal-resistance for over 30 years. They have piezo membrane similar to that in a beeper – a ceramic placed on a plate which is bent from 10 to 100µm. Piezo generators produce high voltages at low current, and a wireless node is going to need, say, 3.3V at tens or hundreds of µA.
The converter has been developed with the Zürich University of Applied Sciences and Swiss chip firm Microdul.
German finger-powered light switch firm EnOcean, which uses electromagnetic generation, has a several patents on its technology, including one patent which it has been claimed covers many or all practical mechanically powered self-generating wireless nodes.
Basic Info on Piezo Switch Technology:
Capacitive switches are currently experiencing a mushrooming growth thanks partly to their use in smartphones. There is no stroke, no moving parts. But capacitive touch switches are not a first choice for every application. Some capacitive touchscreens cannot be used to detect a finger through electrically insulating material, such as gloves. High air humidity or water droplets, for example, can also disturb the touchscreen electrostatic field.
Switches based on the piezoelectric principle generate a charge when under stress. The compressive pressure of a finger push 
causes the (typically disc-shaped) piezo element to bend slightly like a drumhead. Piezo switches produce a single, brief “on” pulse typically used to turn on a semiconductor such as a field effect transistor (FET). In contrast to a mechanical switch, a piezo switch has no moving parts. It can be hermetically sealed with IP protection up to IP69K. This feature predestines it for use under the most adverse conditions.
A piezoelectric element (usually ceramics that include lead zirconate titanate or PZT, barium titanate or lead titanate) generates a charge when under stress. The compressive pressure of a finger push causes the (typically disc-shaped) piezo element to bend slightly like a drumhead.
In contrast to a mechanical switch, a piezo switch has no moving parts. It can be hermetically sealed with IP protection up to IP69K. This feature predestines it for use under the most adverse conditions. Refer https://www.designworldonline.com.
LANGIR Piezo Technology : Finger pressure is applied to the surface of the switch-housing which deflects about 2 microns. 
This pressure activates the piezo crystal that converts this pressure to an electrical signal that is amplified by electronics imbedded within the housing. The LANGIR® technology is based on a single VPM (Versatile Piezo Module) mechanically assembled without the use of adhesives nor soldering. The VPM is encapsulated in a metal, one piece construction housing, custom designed or as per industry standard, creating the most reliable and durable switch and keypad. Refer https://www.langir.com/news/piezo-switch/.
Modutech self-powered /wireless switches are perfect for modular, prefab, or any application where a reconfigurable, movable, non-wired wall switch is preferred.
In addition, Piezoelectric materials are used to manufacture the equipment that goes into your vehicle, and they allow for 
precise, reliable control with repeatability and accuracy after billions of cycles. This is a huge advantage for automotive applications, especially in systems related to fuel economy, performance and safety, where failure could lead to major problems.
Indirect uses of piezoelectric materials in the automotive industry include machines and robots that are used to design, manufacture and test vehicles. The high accuracy and precision of our piezoelectric materials that go into a wide range of transducers, sensors and actuators makes them perfect for indirect automotive applications. From the equipment that’s used to aim the headlights to the precise positioning of a robotic arm for the installation of components, piezoelectric technology has an important role to play in the automotive industry. Refer https://www.americanpiezo.com/markets/automotive.html.
The mechanical performance of a novel micro-switch actuated by PZT piezoelectric multiple-layer cantilever is studied with piezoelectric multiple-layer cantilever analysis model, and a new fabrication process of the micro-switch actuated by PZT piezoelectric multiple-layer cantilever based on Si is presented. By using software of finite element ANSYS7.0, the analyses on modal shapes of micro-cantilever structure are carried out. The relationship between structure parameters and the movement performance and some factors that may have an effect on the performance of this micro-switch are discussed. Furthermore, the displacement of micro-switch applied direct-current working voltage of 0.3 volts is simulated. The results demonstrate that the micro-switch optimized can be applied to system on chip. Refer https://www.researchgate.net/
The piezoelectric effect occurs through compression of a piezoelectric material. Piezoceramic material—non-conductive piezoelectric ceramic or crystal—is placed between the two 
metal plates. For piezoelectricity to be generated, it needs that material to be compressed or squeezed. Mechanical stress applied to piezoelectric ceramic material generates electricity. There’s a voltage potential across the material. The two metal plates sandwich the piezo crystal. The metal plates collect the charges, which creates/produces voltage (lightning bolt symbol), i.e., piezoelectricity. In this way, the piezoelectric effect acts like a miniature battery, because it produces electricity. This is the direct piezoelectric effect. Devices that use the direct piezoelectric effect include microphones, pressure sensors, hydrophones, and many other sensing types of devices. Refer www.electronicdesign.com.
ALGRA Dynasim consists of different laminated layers. In the key area there are ceramic elements called piezopills. The power generates a charge in the piezopills which is used as a switch signal. The top membrane only goes through a small, elastic deformation. That’s why the ALGRA Dynasim keyboard is extremely robust, resistant and long-lasting.
The pathless operation allows a simple and solid construction with a small depth of installation. Furthermore there can be chosen out of many overlay materials.
As initial concept developed above direct cost is estimated at < $8.00 for Electronic Finish Panel
Piezo Electronic Touch Pad – Implementation Ready w/Business Case http://www.algra.ch
