Rotary encoders are pretty interesting pieces of technology. They’re a solid way to accurately measure rotation including the direction. [David] recently wrote some software to handle these input ...

In most keypads, pressing a key closes a contact that bridges two lines in an xy matrix. If you use a microcontroller to detect a key closure, checking the states of (x+y) lines requires an equal ...

Matrix keyboards are commonas an input device in microcontroller-based projects. A conventionalway of connecting a matrix keyboardto a microcontroller is to use multipleI/O pins of the MCU. The MCU ...

Eight-pin microcontrollers offer numerous peripheral features. However, the maximum number of I/O pins available is often limited to six, since two pins would be required for the chip's power supply.

Here’s an interesting article about reading data from shift registers using less than three pins. 74HC165 shift registers are a popular choice for adding inputs to a microcontroller. They have a ...