SmartKnob View is a DIY haptic input knob with WiFi and Bluetooth connectivity

Soon after writing about RoenDi rotary encoder with a built-in color display, readers pointed me to SmartKnob View, a similar-looking project but featuring an ESP32 module for WiFi and Bluetooth connectivity, plus software-configurable end-stops and virtual detents.

The latter is enabled through a brushless gimbal motor paired with a magnetic encoder to provide closed-loop torque feedback control. Just like RoenDi, SmartKnob View comes with a 240×240 round color display but adds tactile feedback so you can change the menu when pressing the display.

SmartKnob View

SmartKnob View specifications:

  • Wireless module – LilyGO Tmicro32 Plys based on ESP32-PICO-V3-02 WiFi and Bluetooth LE SoC (May be changed to ESP32-S3-MINI-1 to enable USB HID support, once Arduino core supports it)
  • Display – GC9A01 1.28-inch 240×240 round LCD covered by a 39.5mm watch glass on rotor
  • Motor – BLDC gimbal motor, with a hollow shaft for mechanically & electrically connecting the LCD
  • USB – 1x USB Type-C 2.0 connector for power and serial data/programming via CH340 USB to TTL chip
  • Sensor – VEML7700 ambient light sensor for automatic backlight & LED intensity adjustment
  • Misc
    • PCB flexure and strain gauges for press detection (haptic feedback provided via the motor)
    • 8x side-firing RGB LEDs (SK6812-SIDE-A) to illuminate the ring around the knob
    • Back plate for mounting using either 4x screws or 2x 3M medium command strips
    • Front cover snaps on for easy access to the PCB

Note it’s currently a work-in-progress project, and not recommended for general use with mechanical and electrical revisions planned. Yet the initial prototype appears to be working pretty well, and the demo is rather cool.

The project is open-source hardware with the design files, Arduino firmware, and instructions available on Github. You’d think this type of niche hardware would only attract a small community of users, but the YouTube video above got over 300k views, plus at least 100k more on Twitter. The popularity of the project may have even caused the recommended motors to go out of stock, and there may not even be further production. There’s currently an open issue on Github to look for replacements, and the PCB design and 3D printed part may change as a result.

Scott Bezek, the developer, does not appear to have plans to manufacture the SmartKnow View, as this is a  side project done during his free time. The Apache 2.0 licence of the project would enable others to manufacture the knob as long as attribution is given.

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1 Comment
2 years ago

Nice thing.

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