Basic 16x2 Character LCD - Black on Green 3.3V

Jargon buster

Plain-language definitions for the technical terms used above.

duty cycle

The fraction of time a signal or power source is switched on during each repeating on/off cycle, usually given as a percentage. It is central to PWM (pulse-width modulation), where adjusting the duty cycle controls things like LED brightness, motor speed or heater power, and on devices such as proximity sensors it can also affect detection range, response speed, accuracy and power use.

LCD

LCD stands for liquid crystal display, a screen technology that uses a backlight and liquid crystals to show images or text. It matters because LCD modules usually need a display driver and enough controller pins or a bus interface to send image data.

LED

A light-emitting diode (LED) is a small electronic component that emits light when current flows through it in the correct direction. Because it only conducts one way, its polarity matters, and a through-hole LED must be soldered the correct way around to light up.

microcontroller

A microcontroller is a small computer on a single chip that runs a stored program and controls connected inputs and outputs such as buttons, sensors, displays and communication interfaces. In a device built around one, it is the part that executes the code and coordinates the device's behaviour.

parallel interface

A parallel interface sends several bits of data at the same time using multiple wires. It can be faster than simple serial connections, but it uses more microcontroller pins, so it is less convenient for small projects with limited wiring space.