Components
The basic building blocks used across the projects — how they work, how to wire them, and where to buy them.
LED (Light-Emitting Diode)
A diode that emits light when current flows the right way through it.
Resistor
Limits current and divides voltage. Its value is printed in colored bands.
Breadboard
Solderless prototyping board — push components in, rearrange freely, no soldering.
Jumper Wires
Flexible pre-made wires for breadboard and module connections.
Push Button (Momentary Switch)
A tactile switch that connects only while you hold it down.
Potentiometer
A knob that varies resistance — read its position as an analog input.
Piezo Buzzer
Makes beeps and tones straight from a digital pin.
RGB LED
Three LEDs (red, green, blue) in one package — mix any color with PWM.
Photoresistor (LDR)
Resistance falls as light rises — read it with a voltage divider.
Servo Motor (SG90)
A small motor that holds a commanded angle from 0° to 180°.
PIR Motion Sensor (HC-SR501)
Detects moving warm bodies and pulses its output HIGH when it sees motion.
Relay Module
An electrically-controlled switch — let a 5V pin switch a much bigger load.
Analog Joystick
Two potentiometers and a button — read X, Y, and a press.
Stepper Motor (28BYJ-48 + ULN2003)
Rotates in precise steps; driven through its ULN2003 board.
Rotary Encoder (KY-040)
An endless knob that reports which way it turned, plus a push.
16x2 Character LCD (I²C)
A two-line text display; the I²C backpack drives it with just two wires.
Soil Moisture Sensor
Reports how wet the soil is as an analog reading.
IR Receiver (VS1838B)
Decodes button presses from a TV-style infrared remote.
NeoPixel / WS2812 LED Strip
Individually-addressable RGB LEDs chained on a single data wire.
NPN Transistor (2N2222 / BC547)
A tiny electronic switch — a small base current controls a big load.
DC Motor
Spins continuously — drive it through a transistor or H-bridge, never straight from a pin.
4x4 Matrix Keypad
16 buttons read through just 8 pins as a row/column grid.
L298N Motor Driver
A dual H-bridge board that drives two DC motors forward and backward.
7-Segment Display
Seven LED bars (a–g) that light up to form the digits 0–9.
Capacitive Touch Sensor (TTP223)
A solid-state touch button — no moving parts; output goes HIGH on touch.
Reed Switch
A magnetically-operated switch — its contacts close when a magnet is near.
Tilt Sensor (Ball Switch)
A switch that opens or closes depending on its angle.
Water Level Sensor
Interleaved traces whose reading rises with how deep the water is.
Thermistor (NTC 10k)
A resistor whose value changes with temperature; read it with a divider.