T-Keyboard-S3 Pro 4-Key USB mechanical keyboard adds rotary encoder, support for daisy-chaining up to six keyboards

Last year, we featured the T-Keyboard-S3, a USB mechanical keyboard with ESP32-S3, and four mechanical keys each fitted with a 0.85-inch color display. The upgraded T-Keyboard-S3-Pro adds a rotary encoder and four magnetic interfaces on each side controlked by an STM32G030 MCU to daisy-chain the host keyboard with up to 5 slave keyboards in a 3×2 grid.

Previously, we featured the ANAVI Macro Pad 12, Macro Pad 10, and Macro Pad 2 programmable keyboards. Feel free to explore those as well.

LILYGO T-Keyboard-S3 Pro specifications:

• Wireless module – ESP32-S3-WROOM-1 used in the host model only
  • MCU –  ESP32-S3R8 dual-core LX7 microprocessor @ up to 240 MHz with Vector extension for machine learning
  • Memory – 8MB PSRAM
  • Storage – 16MB SPI flash
  • Connectivity – WiFi 4 and Bluetooth 5 with LE/Mesh
  • PCB antenna
• Secondary MCU – STMicro STM32G030F6P6 for I2C magnetic connectors
  • CPU – Arm 32-bit Cortex-M0+ CPU, frequency up to 64 MHz
  • Memory – 8KB SRAM
  • Storage – Up to 64 KB of Flash memory with protection
• Displays used for keys
  • Up to 5x 0.85-inch TFT RGB LCDs with 128×128 resolution
  • Active area – 15.2064(H) mm x 15.2064(V) mm
  • GC9107 driver chip with SPI communication
  • The fifth display socket if fitted with a rotary encoder in the host model
• Keys – 5x Kailh hot-swappable mechanical keyboard switches each fitted with a keycap equipped with an LCD (6.35mm spacing), and connected to a WS2812C RGB LEDs
• Rotary encoder – Four-legged copper top pin knob option
• USB – 1x USB Type-C power for power, connection to the host, and programming
• Expansion
  • 4x magnetic (16-pin holder) connection interfaces for quick expansion
  • Supports up to six interconnected devices (2×3 grid layout)
  • 2x STEMMA QT/Qwiic connector (JST-SH 1.0mm 4-pin) for I2C and UART
• Misc
  • 14 programmable WS2812C RGB LEDs
  • ESP32-S3 Boot button in the fifth key (press down)
  • ESP32-S3 reset button for user
  • STM32 reset and boot button in the PCB board
• Power supply – 5V via USB-C port
• Dimensions – 164 x 46 x 42 mm (H)
• Weight – 210 grams

The T-Keyboard-S3-Pro incorporates 14 programmable RGB LED lights powered by the WS2812C chip. While these LEDs can operate at maximum brightness on a single board, reducing brightness to 10% is recommended when interconnecting up to six boards. This limitation addresses heat generation, power supply constraints, and increased impedance in the 5V voltage transmission, ensuring stable operation and preventing excessive power drawn from the USB port.

The board also supports Kailh hot-swappable connectors with a 6.35mm pin spacing, compatible with standard hot-swappable pins and buttons. The KEY5 pin is reused as BOOT-0 for system power-on mode selection, with a default 10K pull-up resistor to provide a stable signal. Internal pull-up configuration in software further enhances reliability. To ensure compatibility with the ribbon cable, the buttons must feature an opening in the center and a spacing greater than 7mm to accommodate the connection.

The T-Keyboard-S3 Pro offers programming support for both the host and slave devices. The host can be programmed using the Arduino-ESP32 library (v2.0.14) and PlatformIO, while the slave supports STM32CubeMX (v1.6.2) and Keil μVision5. LILYGO provides example code and detailed instructions for Arduino and PlatformIO on GitHub. The GC9107 display driver is compatible with popular Arduino graphics libraries such as Arduino_GFX, TFT_eSPI, and LVGL.

The T-Keyboard-S3 Pro is available on AliExpress for $73.48 (host keyboard) and $62.48 (slave keyboard), and you’ll find both on Amazon for $66 and $58 respectively. For more details, visit the product page.

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