the ladder · rung 4 of 10

Level 4 · Motion

Make things spin, wobble, and go.

Motors turn electricity into spin. A diode across the motor catches the voltage kick when it stops — the same kick that would otherwise fry the transistor you learned to trust at Level 3. Same components, new physics.

New in the box

DC motor (3 V) — Turns electricity into spin.
Diode (1N4001) — A one-way street for current. Protects circuits from motor kickback.

with everything through L4, your box now holds 18 component types.

Projects at Level 4

First Spin Your first motor. A switch, a coil, and a diode that catches the voltage kick when the current stops. 15 min · ●●○○○ Handheld Fan Press the button, the fan spins. A tiny finger current commands a hundred-milliamp motor through a transistor. 20 min · ●●●○○ Sunrise Fan Sunrise Alarm with the LED swapped for a motor. The sun rises, the fan starts — an automatic wake-you-up desk breeze. 25 min · ●●●○○ Panic Fan Two buttons, either one fires the fan. Panic Doorbell wearing a motor — an OR gate that spins. 20 min · ●●●○○ Party Spinner One button, three mouths: a spinning motor, a red LED, and a buzzer all fire together. One transistor drives them all. 25 min · ●●●○○ Twin Wheels Two motors from one button — a Level 9 robot drivetrain, five levels early. 25 min · ●●●○○ Dial-a-Spin Dial-a-Brightness with a motor instead of an LED. Twist the knob and watch the fan speed slide from full spin to a slow crawl. 20 min · ●●●○○ Trip Wire Fan Trip Wire Alarm's brain wearing a motor. The wire is intact — the fan is silent. Snap it — the fan spins as the alarm. 25 min · ●●●○○

What you can build so far

Every project at Levels 1–4 draws on the components you now own — earlier projects never stop being useful. With the full L4 box you can tackle any of these 43 projects:

🔦 First Light · 📡 Morse Code Messenger · 🎈 Twin Reds · 🚦 Tabletop Traffic Light · 🔐 The Vault · 🚪 Do Not Disturb Sign · 🤝 Handhold Chain · 🚪 Two-Door Signal · 🚨 Signal Light · 🛟 Escape Hatch · 🧪 The Brightness Lab · 🔔 Door Buzzer · 🎛️ Dial-a-Brightness · 📻 Dial-a-Buzz · 🔧 Continuity Tester · 🚨 Panic Doorbell · 🔈 Whisper Alarm · 🛎️ Two-Tone Doorbell · 🚨 Arm & Ring · 🔔 Twin Bells · 🖐️ Two-Hand Bell · 🔕 Silent Alarm · 🎮 Quiz Buzzer · 🌙 Automatic Night Light · 🌅 Sunrise Alarm · 🍪 Cookie Jar Alarm · 🪤 Trip Wire Alarm · 🌡️ Warm Hand Alarm · 📖 Reading Light · 🏝️ Vacation Nightlight · 📚 Study Lamp · 🌆 Curfew Beeper · 🤒 Fever Beeper · 🌇 Dusk Chorus · 🎺 Warm Hand Chorus · 🌀 First Spin · 💨 Handheld Fan · 🌞 Sunrise Fan · 🆘 Panic Fan · 🎉 Party Spinner · 🚗 Twin Wheels · 🎚️ Dial-a-Spin · 🕸️ Trip Wire Fan