Whether dealing with dirty/dusty environments or applications with color variations or transparent targets, Pepperl+Fuchs’ F77 series of ultrasonic sensors offer an alternative to background suppression photoelectronic sensors. The devices also suit applications in which pinpoint accuracy of a photoelectric beam is too focused to accurately sense the target. According to the company, the sensors are 100% insensitive to color, provide 100% reliable clear object detection, and ignore holes and ridges, which is key for printed-circuit-board apps. They are highly immune to acoustic interference and have minimal deadband. Measuring 31 by 11 by 23 mm, the sensors deliver up to 50-Hz switching frequency for fast response times. Operating temperature ranges from -25 to 70°C. Various model styles are available, including diffuse (up to 400-mm sensing range), retroflective (up to 400-mm sensing range), and thru-beam (up to 800-mm sensing range).