Sep 02, 2026Povilas Dumcius1 min read
Build ideas: Rotary Encoder

Build ideas: Rotary Encoder

I've used rotary encoders for years and never actually watched what happens inside one. So, this week I made three things with it.
Inside there are two contacts, A and B. When you turn the knob they pulse, and they're slightly out of phase: one always fires a little before the other. Turn the other way and the order flips. That's the whole trick. The board counts the pulses for position and looks at the order for direction

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Visualiser

The AX22-0003 is a rotary encoder with a push button in the shaft. It plugs into any Genesis port. Unlike a potentiometer, it has no start and no end. It turns forever, and every detent you feel is one step.

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Bubble Popper

Bubble popper. Turn the knob to move the cursor along the bottom of the display, press to fire. Bubbles drift down. Miss five and it's over.

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Menu System

Rotary encoders are great for navigating menus on the screen.

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Combination Lock System

Enter the correct password to move the servo

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Fork it

All three are in Studio. Open them, change the bubbles to something else, add a page to the menu, plot something else on the dashboard. If you build something, send me a photo. I show builds every week.

Parts: Genesis Mini, rotary encoder (AX22-0003), IPS display, Servo module, Passive buzzer

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