parts
Every part, explained from zero.
One page per component in the toolbox, in the order the ladder hands them to you. What it is, how it works with the numbers shown, the mistakes everyone makes, and a live circuit to poke at.
Level 1 · Light
- What a 3×AA battery pack does — 3×AA battery pack (4.5 V): The push that gets electrons moving. 4.5 volts — safe to touch.
- How a breadboard works inside — Solderless breadboard: Your building plate. Push parts in, pull them out, no glue, no solder.
- What jumper wires are for — Jumper wires: The roads electricity travels between parts.
- LED forward voltage explained — Red LED (5 mm): A tiny light with a one-way door — current only flows long-leg-in.
- Yellow LED resistor calculation — Yellow LED (5 mm): Like the red LED, in caution-light yellow.
- Why green LEDs need 2.1 volts — Green LED (5 mm): Like the red LED, in go-light green.
- What a 220 ohm resistor is for — 220 Ω resistor: A speed bump for electricity. This one protects LEDs.
- When to use a 1k ohm resistor — 1 kΩ resistor: A bigger speed bump — about five 220s stacked.
- What a 10k ohm resistor is used for — 10 kΩ resistor: A big speed bump, used for sensing tricks later.
- How a slide switch works — Slide switch: Opens or closes the loop. On means the loop is complete.
- How a tactile push button works — Push button (tactile): A switch that only stays on while you press it.
Level 2 · Sound
- Active vs passive buzzer explained — Active buzzer (3–5 V): Give it power, it beeps. It makes its own tone inside.
- How a potentiometer works — 10 kΩ potentiometer: A resistor with a knob — twist to change the speed bump size.
Level 3 · Sense
- How an LDR light sensor works — Light sensor (LDR): A resistor that changes with light: bright = small, dark = huge.
- How a thermistor works — Temperature sensor (10 kΩ thermistor): A resistor that changes with temperature.
- How a 2N2222 transistor switches — NPN transistor (2N2222): An electric switch flipped by electricity — a tiny current controls a big one.
Level 4 · Motion
- How a small DC motor works — DC motor (3 V): Turns electricity into spin.
- What a 1N4001 diode does — Diode (1N4001): A one-way street for current. Protects circuits from motor kickback.
Level 5 · Control
- How an SG90 micro servo works — Micro servo (SG90): A motor that turns exactly as far as you tell it.
Level 6 · Logic
- What a 555 timer chip does — 555 timer chip: The most famous chip ever — it blinks, beeps, and keeps time.
- What a 10 µF capacitor does — 10 µF capacitor: A tiny rechargeable bucket for charge — fills and empties to keep time.
- What a 100 nF capacitor is for — 100 nF capacitor: A very small charge bucket that smooths out electrical wobbles.
Level 7 · Code
- What an Arduino Nano is — Arduino-compatible board (Nano): A brain for your box. Now every part you own can be programmed.
Level 8 · Environment
- How the DHT11 sensor works — Temperature + humidity sensor (DHT11): Reads the room: how warm, how humid.
- How a soil moisture sensor works — Soil moisture sensor: Tells you when a plant is thirsty.
Level 9 · Robotics
- How the L293D motor driver works — Motor driver (L293D): Lets your small brain safely boss around big hungry motors.
- What TT gear motors do for a robot — Gear motors + wheels (pair): Slow, strong spin — the legs of every robot you will build.
Level 10 · Connected
- What an ESP32 board is — ESP32 Wi-Fi board: A brain with Wi-Fi. Your projects can now text you.