This optical keyboard/keypad is a low-cost optical user input device capable of deployment underwater, explosive gas areas, or in other locations where hermetic sealing is desirable. It does not use capacitive, magnetic, mechanical, acoustic, or visible-light coupling. The reflection of an infrared beam is used at each keysite to determine finger presence. No part of this device need be in actual contact with the outside medium; a transparent window (possibly of variable thickness) may optionally be used. Emphasis is on ease of construction, low component count and cost, and low software processing cost. A current tradeoff is lack of operation capability in direct sunlight, which can be improved by inverting the present phototransitor biasing and additional software work.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.