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mouser.com/vishay / 19 Their large touch buttons can be replaced by optical switches with LED backlighting that are flush to the panel surface, which will reduce the build-up of grime and simplify the cleaning process. With proper backlighting design, these optical switches can be made to look as large as the touch buttons they've replaced. Beyond ease of cleaning, another benefit of optical switches is that they work when workers are wearing gloves, be it for warmth in cold environments or latex gloves in chemical or medical environments. Capacitive switches don't offer this advantage. Another benefit is that the entire control panel can be watertight. Granted, the key interface would have to be covered, but the optical buttons can be sealed more easily. Finally, the buttons can remain as singular units or they can be combined under one cover glass. The VCNT2025X01 optical sensor has been used by control panel manufacturers to migrate from mechanical buttons to optical switches. It's a reflective sensor with the 940nm infrared emitter and the phototransistor on the same plane, and the output current flows when the infrared light reflects off an object. The device's foil-assisted molding (FAM) package eliminates any light leaking from the emitter to the phototransistor, which means the only signal being received is the reflected signal. A visible light-blocking filter over the phototransistor can further improve the signal-to-noise ratio. There is no red glow from the IR emitter because it operates at a 940nm wavelength. With a forward current of 20mA powering the emitter, the typical output current of the sensor is 6.6mA, which can be fed directly into a microcontroller without the need for amplification. While not directly applicable to industrial applications, the VCNT2025X01 sensor is AEC-Q101 qualified for a high degree of reliability. Should the glass or plastic cover be particularly thick or have a low infrared transmissivity, the device's infrared emitter can be replaced by a vertical-cavity surface-emitter laser (VCSEL), which has higher power and a narrower beam. This is the main feature of the VCNT2030. Learn More Learn More VCNL4200 Proximity & Ambient Light Sensor VCNT2025X01 Reflective Optical Sensor The VCNL4200 is a long-range proximity sensor that can be used to detect an object up to 1.5m away and can also determine if the object is just passing by or actually approaching the sensor. With these capabilities, the VCNL4200 is widely used in consumer thermostats with large displays, where instead of showing the temperature at all times, it is only displayed when a user approaches the device. In addition, the sensor is becoming more popular in industrial actuation applications. Unlike the VCNL2025X01 and VCNT2030, the output of the VCNL4200 is a digital count read via an I 2 C interface, and can be as high as 65,535 or 16-bit. The closer an object is to the display, the higher the count. This same application can be used with industrial displays to reduce power consumption and provide information only when someone is present. Of course, it can also be used in other applications besides displays. Much like a beam-break application, it can be used to turn on or off a process when an object or person is present. As a reflective sensor, the VCNL4200 eliminates the need to align an emitter and detector to create the beam, and power is needed only on one side.