This ESP32-Powered Smartwatch Uses Two Screens to Display Information

Motivations for creating a dual-screen watch

Smartwatches, or tiny powerful computers worn on one's wrist, have massively taken off in popularity within the last decade and especially after the release of the Pebble Watch. The leading manufacturers/designers- Apple, Samsung, Garmin, and FitBit, all have single-screen watches in their product lineups which can limit the amount of multitasking due to the space constraints. To explore this idea of a true multitasking device, David Truong came up with a creative solution: a smartwatch with two screens instead of just one.

A previous project

Released in late 2022, Truong's initial attempt at building a smartwatch with dual screens was a very interesting process. He started by determining what features were most important, and those ended up being the typical date/time tracking, health monitoring, fitness measurements via an MPU6050 accelerometer and gyroscope, and some basic networking utilities for determining which Wi-Fi networks are nearby. The project was quite successful at achieving these goals at a low cost. However, the resulting size meant it was cumbersome to wear and use, meaning that a second revision was in order.

Version two

Most of the changes in this update were focused on reducing the footprint and volume of the watch's internals for better usability. Although Truong did not design and fabricate a PCB, he was still able to accomplish this task by cutting the perf board, switching to a far smaller wire gauge, and minimizing the space between parts, all while maintaining the same functionality. Along with the new layout was also an updated 3D printed case to house the components.

Interacting with the watch

Wearers are able to navigate the GUI on either screen by clicking the four buttons on the right or the two on the left depending on the current mode. OLED burnout is reduced as much as possible by aggressively entering sleep mode, and this comes with the added benefit of increasing battery life. The two screens allow for one application to be running on top while the other runs below it, all simultaneously.

Features

Similar to the first version, the watch contains several modules that give the user ample amounts of data regarding their surrounding environment and themselves. The onboard GPS module provides coordinate tracking, speed/altitude measurements, and extremely accurate timekeeping. When GPS satellites are not available, the ESP32's internal real-time clock (RTC) is used, with external RTC compatibility coming soon.

Heart rate detection with an external lead and movements on an attached MPU6050 accelerometer/gyroscope module are recorded for later analysis and display regarding activity tracking. Meanwhile, the timer function allows for lap times and countdowns to be performed. Finally, simplified Tetris and Pong games were included to showcase the hardware, as well as the aforementioned Wi-Fi scanning utility.

The result

The dual-screen ESP32 watch is a very unique piece of hardware with so many capabilities that can be viewed at the same time. To read more about Truong's project, you can visit his write-up here.