Level 2 · Sound — TinyOhms

Door Buzzer Your first sound circuit — a real doorbell for your bedroom door. 20 min · ●○○○○

Pocket Beeper Level 2's answer to First Light: battery, push button, buzzer. Three parts, one loop, one loud beep — no resistor and no LED to explain. 10 min · ●○○○○

Dial-a-Brightness Twist a knob and watch the LED fade up and down — your first "how much" input. 20 min · ●●○○○

Dial-a-Buzz Dial-a-Brightness for sound — one knob rides the buzzer between full alarm and library silence, with no button in the way. 15 min · ●●○○○

Continuity Tester Your first real tool — two probe wires that beep and light up whenever the tips touch anything that conducts. 20 min · ●●○○○

Panic Doorbell Two buttons wired so either one fires the same buzzer and light — your first OR gate. 20 min · ●●○○○

Whisper Alarm A doorbell with a volume knob — the pot lives in the buzzer lane, so twisting it changes the beep without touching the light. 25 min · ●●○○○

Two-Tone Doorbell Two call buttons, one doorbell: LOUD rings the buzzer and lights the porch LED; QUIET starves the buzzer and shows why it can't just be dimmed. 25 min · ●●○○○

Arm & Ring A doorbell that ignores you unless a hidden slide switch is armed first — series-AND with sound, plus an 'armed' LED that shows the state. 20 min · ●●○○○

Twin Bells One doorbell button rings two buzzers in parallel — one in your room, one in the kitchen — with a slide switch that mutes just the bedroom bell at night. 20 min · ●●○○○

Two-Hand Bell Two push buttons in series feeding a buzzer and an LED — both hands must stay pressed for the alarm to sound. 20 min · ●●○○○

Silent Alarm Three panic buttons wired in parallel, all inside an armed lane — any one of them fires the buzzer, and a small LED tells you the alarm is watching. 25 min · ●●○○○

Quiz Buzzer Two teams, two big buttons: yours lights your LED and rings your buzzer, theirs does the same on their side. Two independent doorbells sharing one battery. 20 min · ●●○○○

Loud/Polite Doorbell One doorbell button, one buzzer, and a slide switch that shorts across a 1 kΩ resistor — flip it to swap between a startle-loud beep and a scratchy whisper. 20 min · ●●○○○

Duet Doorbell One button, two buzzers in parallel — one wired direct at full 30 mA, one starved through a 220 Ω to about 12 mA — voicing together at two different loudnesses. 20 min · ●●○○○

Vault Chime Three slide switches in a line, a buzzer and a red LED hanging off the end — the chime only sings and glows when every single switch is closed. 20 min · ●●○○○

Hidden Mute A doorbell with a secret slide switch tucked inside just the buzzer lane: flip it and the ring button still lights the LED, but the sound stays off. 15 min · ●●○○○

Power Pilot A green pilot LED that glows the whole time the battery is plugged in, next to a red alarm LED and buzzer that only fire when the button is pressed. 15 min · ●●○○○

Shared Knob One pot sits above the merge of two parallel LED lanes (red + yellow). Twist it and BOTH LEDs fade together — the knob throttles the shared rail. 15 min · ●●○○○

Level 2 · Sound

New in the box

Projects at Level 2

What you can build so far