If you are looking for an “ESP32 round OLED smartwatch,” the documented concept is a useful starting point—but its screen is not OLED. It uses a 1.28-inch GC9A01 round IPS LCD, connected to a Lolin D32 Pro ESP32 board. The project describes a breadboard prototype and setup path, not a finished, tested everyday watch.
What the ESP32 round-watch concept actually includes
The project, attributed to Arnov Sharma in an Instructables guide reproduced on Scribd, names a Lolin D32 Pro ESP32 development board, a 1.28-inch GC9A01 round LCD, an RTC module, a breadboard and jumper wires. Its screen is a 240 × 240-pixel IPS LCD with an SPI interface—not an OLED panel. The stated active display area is about 32.4 mm across; the module itself is larger.
This is best understood as a component-level maker concept. The parts list and display setup provide a foundation for experimentation, while a custom battery-powered PCB and additional watch behavior are described as future development. The guide does not establish that the result is a finished wearable or provide a measured battery runtime. Read the project guide.
Display and wiring: check the exact module and board
Confirm the panel and its electrical details
The GC9A01 module described by the project uses four-wire SPI. Its guide gives an operating-voltage description of 3.3 V/5 V, but breakout boards can differ in pin labels and electrical implementation. Check the documentation for the exact module you have before connecting power; do not assume every GC9A01 board accepts the same voltage. The guide points readers to Waveshare’s 1.28-inch LCD module documentation for display information.
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- Size: 1.28";Resolution:240x240;Driver chip:GC9A01
- Interface mode: SPI;Color: full color RGB
- Driving voltage: 3-5V;Perspective: IPS full perspective
- Operating temperature:-20-70℃
- Display size: 32.4mmx32.4mm;Overall dimensions:38mmx45.5mmx3.2mm
Use GPIO assignments as board-specific examples
The project configures the display with Bodmer’s TFT_eSPI library and selects the GC9A01 controller in the library setup. Its wiring example connects display data input to ESP32 MOSI and display clock to SCK, alongside chip-select, data/command, reset, power and ground. Treat its GPIO numbers as an example for the named Lolin D32 Pro, not a standard pin map for all ESP32 boards. Check your own board’s pinout and the display breakout’s labels before wiring.
Validate the screen before building the watch interface
- Check the hardware: identify the controller, pin labels and voltage requirements on your exact display module, then verify the corresponding pins on your ESP32 board.
- Configure TFT_eSPI: select the GC9A01 controller and set up the display pins for your board rather than blindly copying assignments from a different ESP32.
- Run a display example: confirm that the panel initializes and draws correctly. Check orientation and color rendering before adding a clock face.
- Build the interface: once the display is working, add the watch screen and decide how the device will get and retain time.
The guide’s code listings are not evidence that every listing has been recently tested, so treat this sequence as a practical bring-up approach rather than a guarantee that a particular configuration will work unchanged.
Rank #2
- Compact design at 45.5x48x11.5mm and 3-5V operation is ideal for wearables and embedded projects
- High-brightness backlight ensures excellent readability even in bright outdoor conditions
- Vivid 1.28" round color display with full-view angle for clear visibility from any direction
- Easy Integration via 4-wire SPI and built-in GC9A01 driver IC compatible with Arduino, ESP32, Raspberry Pi
- 1.28" TFT LCD full-viewing angle display and round screen suitable for smart watches, dashboards, embedded devices
Timekeeping and battery power are still design decisions
The parts list includes an RTC module, which can retain time locally. The guide’s proposed later version considers fetching time over the internet and entering sleep after inactivity; these are future possibilities, not demonstrated features of the described revision. Internet time depends on connectivity, while sleep behavior and its effect on power use would need to be implemented and validated.
The author also outlines a future PCB using an ESP32-WROOM-32 module, battery management and a 3.7 V LiPo connection. The guide does not specify battery capacity, power measurements, charging-safety details, runtime, enclosure protection or wearable comfort. Those are open engineering questions, not established results for this concept.
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- 1.28 Inch TFT LCD Display Module Round RGB 240*240 GC9A01 Driver 4 Wire SPI Interface
- Interface mode: SPI;Color: full color RGB
- Driving voltage: 3-5V;Perspective: IPS full perspective
- Operating temperature:-20-70℃
- Size: 1.28";Resolution:240x240;Driver chip:GC9A01
How it compares with other ESP32 watch projects
Other ESP32 watch platforms take different approaches. They are useful points of comparison, not drop-in replacements for the GC9A01 parts or proof that firmware can be transferred between projects.
| Project | What its documentation describes | Best comparison point |
|---|---|---|
| GC9A01 breadboard concept | 1.28-inch, 240 × 240 IPS LCD with SPI; Lolin D32 Pro board and RTC in the parts list. | Hands-on wiring and component-level learning; battery system remains proposed. |
| Waveshare ESP32-C6-Touch-AMOLED-2.06 | Watch-shaped development board with a 2.06-inch, 410 × 502 AMOLED touchscreen, ESP32-C6, IMU, RTC and battery interface. Waveshare lists Arduino IDE and ESP-IDF support. | More integrated hardware and a larger AMOLED screen. See the manufacturer’s documentation. |
| Bellafaire ESP32 Smartwatch | Repository documentation describes an ESP32-WROOM watch, a companion Android app and firmware versions with different sleep approaches. | An existing firmware-and-app starting point; check project details and compatibility before relying on it. See the project repository. |
| OpenTimeWatch | Documentation describes ESP32-S3 support and open hardware and software. Its activity view is explicitly marked dummy/not implemented. | Open development and feature completeness. See the project documentation. |
For another distinct approach, Espressif’s February 13, 2023 profile of maker Philippe Cadic’s 603-200 Morphwatch describes an ESP32-PICO-D4 design with 192 LEDs arranged in four circles, plus Wi-Fi/Bluetooth, ESP-NOW, an RTC, a vibration motor, USB-C and buttons. It is an LED-based experiment, not a GC9A01 LCD watch. Read Espressif’s project profile.
Quick Recap
Rank #4
- High-brightness backlight ensures excellent readability even in bright outdoor conditions
- Vivid 1.28" round color display with full-view angle for clear visibility from any direction
- Compact design at 45.5x48x11.5mm and 3-5V operation is ideal for wearables and embedded projects
- Easy Integration via 4-wire SPI and built-in GC9A01 driver IC compatible with Arduino, ESP32, Raspberry Pi
- 1.28" TFT LCD full-viewing angle display and round screen suitable for smart watches, dashboards, embedded devices
Which route makes sense for your build?
- Choose the GC9A01 concept if your goal is to learn display wiring and build around discrete ESP32 components, and you are comfortable resolving board-specific pin setup.
- Consider an integrated development board if you want a watch-shaped platform with a touchscreen and onboard components; confirm that its display, framework and available firmware suit your project.
- Start from an existing watch repository if adapting firmware and an app is more appealing than designing the software structure yourself. Check current project documentation for supported hardware and unfinished features.
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