Actuators: the device's hands and voice
An actuator is the part that does something after the brain decides. Sensors listen; actuators act.
| Actuator | What it does | Example use |
|---|---|---|
| LED | Gives light | Shows "ON" or warns of danger |
| RGB LED / LED strip | Glows in any colour | Mood lights, party lights |
| Buzzer | Beeps | Alarms and reminders |
| Small speaker + MP3 player | Plays sounds and voices | "Welcome home!" messages |
| Display screen (OLED, LCD) | Shows words and numbers | Temperature display |
| DC motor | Spins round and round | Wheels of a robot car, fans |
| Servo motor | Turns to an exact angle | Opening a dustbin lid or a gate |
| Water pump | Pushes water | Watering plants |
| Relay | A switch the brain can flip | Turning a lamp or fan on and off (only a qualified electrician does wall-socket wiring) |
Why motors need helpers
The brain's pins are weak; they can light a small LED but cannot spin a motor. So motors use a helper board called a motor driver, and big things like lamps use a relay. Think of it like a manager (the brain) giving orders to a strong worker (the driver) who does the heavy lifting.