Tiny Keyboard Transforms Smartwatch Into a Desktop PC

Lilygo's Watch-Keyboard-C3
(Image credit: Lilygo)

Have you ever wished your smartwatch was more of a computer and less of a fashion item? Have you ever felt the need to type on keys that are surely too small for normal human fingers to use? The dream of the 1980s was a computer the size of a watch, and in the 21st century we are gifted with this and more. Chinese company Lilygo, whose products we’ve featured before, harks back to the 1980s aesthetic with this tiny Bluetooth keyboard, as spotted by CNX Software.

It's cute, but the amount of actual use you can get out of it is questionable. And sadly, you'll require a specific smartwatch, so there's no turning your Apple Watch into a productivity machine this time. The Watch-Keyboard-C3, as it's snappily known, connects to an ESP-32 C3 microcontroller and a LilyGo T-watch. The watch is included with the keyboard bundle if you don't have one. There's also an optional audio module with a mic and speaker.

The mini keyboard connects over Bluetooth, Wi-Fi 4 for all your wireless networking needs, and a USB-C port for power and data. There's also a three-axis accelerometer on board, really designed for counting steps but with the right code it could be used as a gesture control input system. The tiny computer can be programmed via Arduino tools; there's no desktop OS on this one. In addition, there's some sample code on GitHub in two repositories, but not much else regarding documentation or tools. 

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Tiny computer vs Raspberry Pi Pico
Row 0 - Cell 0 ESP-32 C3RP2040 (Raspberry Pi Pico)
ControllerC3 RISC-VDual-core Arm Cortex-M0+ (32-bit)
Speedup to 240 MHzup to 133 MHz
Voltage3.3V / 5V5V
Flash storage4MB2MB
GPIO30 pins26 digital i/o
Interfaces2x SPI, 2x I2C, 2x UART2x I2C, 2x I2S, 1x IR, 4x SPI, 3x UART, Bluetooth, WiFi (W version)

The ESP32-C3 was announced in November 2020 and it is part of the larger ESP32 range of boards which started way back in 2016. The ESP32 microcontrollers have become popular thanks to its low cost, plentiful supply and ease of use. The many models of ESP32 come in various configurations. Some offering single or dual-core CPUs with speeds reaching 240 MHz and up to 512KB of SRAM. With faster CPU speeds and more RAM than a Raspberry Pi Pico W, ESP32's are a good choice for the established maker.

The Keyboard-C3 is available right now from AliExpress for just shy of $50, and you can probably get it for less with an AliExpress promo code, if you want the whole package and don't already have a compatible smartwatch.

Ian Evenden
Freelance News Writer

Ian Evenden is a UK-based news writer for Tom’s Hardware US. He’ll write about anything, but stories about Raspberry Pi and DIY robots seem to find their way to him.