EC11 Rotary Encoder with Switch and 20mm Knob Cap | ATMOSFÆR ENGINEERING

Mechanical rotary encoder with integrated push-button switch and aluminum knob cap. Generates quadrature pulse signals for bidirectional rotation detection. Ideal for volume controls, menu navigation, parameter adjustment, and user interface applications with Arduino, ESP32, and other microcontrollers. Includes plum-style shaft coupling for secure knob attachment.

Technical Specifications:

• Model: EC11 (standard rotary encoder)
• Encoder Type: Incremental quadrature encoder
• Pulses Per Revolution (PPR): 20 detents (20 positions per rotation)
• Shaft Type: Plum/D-shaft (flat on one side) for secure knob mounting
• Shaft Diameter: 6mm
• Shaft Length: ~15mm
• Rotation: 360° continuous (no stops)
• Switch: Built-in momentary push-button (SPST)
• Operating Voltage: 5V (typical, compatible with 3.3V logic)
• Output Type: Mechanical contact (requires pull-up resistors)
• Contact Resistance: <5Ω
• Lifespan: 30,000 rotations (typical)
• Operating Temperature: -30°C to +70°C
• Mounting: Panel mount with threaded bushing and nut

Knob Cap Specifications:

• Diameter: 20mm
• Material: Aluminum alloy (anodized finish)
• Color: Black, silver, or various (depends on variant)
• Mounting: D-shaft compatible with set screw

Pin Configuration (5 pins total):

• CLK (A): Encoder output A (clock)
• DT (B): Encoder output B (data)
• SW: Push-button switch
• GND: Common ground (2 pins - encoder and switch share ground)

Features:

• Quadrature output for direction detection
• Integrated push-button for select/enter function
• Smooth rotation with tactile detents
• Durable metal construction
• 360° continuous rotation (no mechanical stops)
• Compatible with 3.3V and 5V logic
• Secure D-shaft prevents knob slipping

Working Principle:

• Rotation generates offset pulse trains on CLK and DT pins
• Clockwise: CLK leads DT by 90°
• Counter-clockwise: DT leads CLK by 90°
• Microcontroller reads pulse sequence to determine direction and count

Typical Circuit:

• CLK → GPIO with 10kΩ pull-up to VCC
• DT → GPIO with 10kΩ pull-up to VCC
• SW → GPIO with 10kΩ pull-up to VCC
• GND → Ground

Applications:

• Audio volume and tone controls
• Menu navigation systems
• Parameter adjustment interfaces
• 3D printer control panels
• Smart home controllers
• Mixing consoles and DJ equipment
• Function generators and test equipment
• Arduino/ESP32 user interfaces
• DIY synth and MIDI controllers

Programming Notes:

• Use interrupt-driven code for reliable direction detection
• Debouncing required (hardware or software)
• Libraries available: Encoder.h (Arduino), RotaryEncoder
• Can detect rotation speed and direction simultaneously

Compatible with Arduino, ESP32, Raspberry Pi, STM32, and any microcontroller with GPIO and interrupt support. Includes mounting hardware (nut and washer).