T-Keyboard-S3 Pro based on ESP32-S3 with Addition of Rotary Encoder and up to 6 Keyboards Daisy-chaining Support

T-keyboard-S3 is a mechanical keyboard with ESP-S3 featuring 0.85 inch color displays mechanical keys. Now its upgraded version T-keyboard-S3 Pro has been launched. This keyboard takes things a step further with the addition of a rotary encoder and magnetic expansion interfaces. These interfaces are controlled by the STM32G030 MCU, enabling users to daisy-chain the host keyboard with up to five slave keyboards in a 3×2 grid layout.

This updated version of the T-Keyboard-S3 is a versatile and feature-rich tool for users who need customizable input devices with advanced connectivity and expansion options. Whether for personal use or as part of a larger setup, this Keyboard Pro stands out with its new rotary encoder, daisy-chaining capabilities, and seamless programming support.

LILYGO T-Keyboard-S3 Pro Specifications

Wireless Module:  ESP32-S3-WROOM-1 (Host model only)

MCU: ESP32-S3R8 Dual-core LX7 microprocessor (up to 240 MHz) includes the machine learning Vector extension.

Memory: 8MB PSRAM and 16MB SPI flash

Connectivity: Wi-Fi 4, Bluetooth 5 (LE/Mesh) and PCB antenna

Secondary MCU: STMicro STM32G030F6P6 for I2C magnetic connectors

CPU: Arm 32-bit Cortex-M0+ (up to 64 MHz)

Memory: 8KB SRAM with 64KB Flash (with protection)

Displays:

5x 0.85-inch TFT RGB LCDs (128x128 resolution)

Active Area: 15.2064mm (H) x 15.2064mm (V)

Driver Chip: GC9107 with SPI communication

Fifth display socket may include a rotary encoder in the host model

Keys:

5x Kailh Hot-Swappable Mechanical Switches (with LCD-equipped keycaps, 6.35mm spacing)

Each key connected to a WS2812C RGB LED

Rotary Encoder: Four-legged copper top pin knob option

USB: 1x USB Type-C for power, connection to the host, and programming

Expansion:

4x Magnetic 16-pin connection interfaces for easy expansion

Supports up to 6 interconnected devices (2x3 grid layout)

2x STEMMA QT/Qwiic Connectors (JST-SH 1.0mm 4-pin) for I2C and UART

Miscellaneous Features:

14 programmable WS2812C RGB LEDs

ESP32-S3 Boot button on the fifth key

ESP32-S3 Reset button for user

STM32 Reset and Boot button on the PCB

Power Supply: 5V via USB-C port

Dimensions and Weight:

164 x 46 x 42 mm (H) dimension 

210 grams weight

The WS2812C chip powers 14 customisable RGB LED lights on the T-Keyboard-S3-Pro. When connecting up to six boards, it is recommended to lower the brightness to 10% even though these LEDs can function at full brightness on a single board. In order to ensure stable operation and avoid excessive power consumption from the USB port, this precaution helps manage heat generation, power supply limits, and the increased impedance in the 5V voltage transmission.

Standard hot-swappable buttons and pins can be used with the board's Kailh hot-swappable connections, which have a 6.35mm pin spacing. In order to select the system power-on mode, the KEY5 pin acts as BOOT-0. By default, a 10K pull-up resistor is used to keep the signal steady. Reliability is further enhanced by the software's internal pull-up setup. The buttons should have a central opening and a minimum 7mm spacing to allow for the ribbon cable connection in order to guarantee compatibility.

Programming and Compatibility

Both the host and slave devices offer versatile programming options. The host can be programmed using the Arduino-ESP32 library (v2.0.14) and PlatformIO, while the slave can be programmed with STM32CubeMX (v1.6.2) and Keil μVision5. LILYGO provides example code and comprehensive instructions for both development environments on GitHub. The GC9107 display driver is compatible with well-known Arduino graphics libraries such as Arduino_GFX, TFT_eSPI, and LVGL.