LILYGO T-HMI ESP32-S3 2.8" Resistive Touch Display Board

Specifications

• Microcontroller: ESP32-S3R8 (Dual-core LX7, up to 240 MHz)

• Flash Memory: 16MB

• PSRAM: 8MB

• Wireless: Wi-Fi (802.11 b/g/n) & Bluetooth 5.0 (LE)

• Display Size: 2.8 inches diagonal

• Display Driver: ST7789

• Interaction: Resistive Touch Screen (Stylus included)

• Power Inputs: USB Type-C, 5V DC Socket, JST 2.0mm Battery

• Expansion: 3x Grove Connectors (UART, I2C, IO)

• Storage: MicroSD (TF) Card Slot

• Dimensions: 90mm (L) x 50mm (W) x 12.5mm (H)

Key Applications and Projects

• Industrial Control Panels: Utilizing the resistive touch screen for operating CNC machines, 3D printers, or workshop equipment while wearing heavy protective gloves.

• Smart Home Dashboards: Building a wall-mounted central hub to securely control Home Assistant entities, lights, and thermostats over the local Wi-Fi network.

• Weather & Environment Stations: Plugging BME280 sensors directly into the Grove I2C port and logging long-term climate data to the SD card, visualized via an interactive UI.

Unlock New Capabilities (Project Evolution) The Ultimate Universal Shop Controller: Don't limit this board to just displaying data! Use the onboard Grove UART port to connect the T-HMI directly to a heavy-duty relay module or motor driver. You can program a custom LVGL interface using SquareLine Studio that features giant, highly visible touchscreen buttons. Because the screen is resistive, you can securely mount this display directly to your workbench and control your shop vacuums, lighting, or soldering fume extractors with the tap of a gloved finger or the tip of a tool!

PACKAGE INCLUDED

• 1 x LILYGO T-HMI ESP32-S3 Board

• 1 x Resistive Screen Stylus

• 1 x JST 2.0mm Battery Power Cable

Downloads & Links

• LILYGO T-HMI Github Link

FREQUENTLY ASKED QUESTIONS (FAQ)

1. What microcontroller drives this board? It is powered by the Espressif ESP32-S3R8 dual-core microprocessor.

2. What is the difference between capacitive and resistive touch? Capacitive screens (like on your smartphone) sense the electrical properties of your bare finger. Resistive screens (like on the T-HMI) consist of two flexible layers that register physical pressure. This means the T-HMI can be operated with gloves, the edge of a credit card, or the included stylus.

3. Why are my touch coordinates inaccurate? Resistive touch screens require a software calibration step. When writing your firmware (using a library like TFT_eSPI), you must run a touch calibration sketch to map the raw analog X/Y voltages to the specific pixel resolution of the 2.8-inch screen.

4. How much Flash memory and RAM does it have? It features a massive 16MB of Flash memory and 8MB of PSRAM, which is essential for storing and rendering large image assets and UI fonts.

5. What are the connectors on the top of the board? These are three standardized Grove connectors. They are mapped internally to UART, I2C, and general-purpose IO, allowing you to plug in hundreds of compatible external sensors without soldering.

6. How can I power the board? You have three options: USB Type-C, a 5V DC barrel jack, or a 3.7V LiPo battery via the JST connector. Caution: Do not plug in the 5V DC power supply and the USB Type-C cable at the same time.

7. Does the board charge the attached battery? Yes, connecting power via USB-C or the 5V DC jack will safely charge an attached 3.7V LiPo battery.

8. What does the physical slide switch do? The switch located on the side of the board physically toggles the main power ON or OFF, saving you from having to unplug the battery or DC adapter when shutting down.

9. Can I log data locally? Yes, the board features a built-in MicroSD (TF) card slot on the bottom edge.

10. How do I put the board into bootloader mode manually? Press and hold the "Boot" button, press and release the "RST" (Reset) button, and then release the "Boot" button. The board will now accept new firmware uploads via USB.

11. What settings should I use in the Arduino IDE? Select the "ESP32S3 Dev Module". Ensure you set "USB CDC On Boot" to Enabled, Flash Size to 16MB, and PSRAM to "OPI PSRAM".

12. Does it support Wi-Fi and Bluetooth? Yes, it features native 2.4 GHz Wi-Fi (802.11 b/g/n) and Bluetooth 5.0 (LE).

13. What GUI libraries are recommended for this board? Because of its high resolution, powerful S3 chip, and large PSRAM, this board is highly recommended for use with LVGL (Light and Versatile Graphics Library) or the TFT_eSPI library.

14. Can I use an external Wi-Fi antenna? The board features an onboard antenna by default, but it does include a tiny u.FL/IPEX connector on the PCB for attaching a high-gain external antenna if required. (Note: Moving a zero-ohm resistor is usually required to switch paths).

15. What are the exact dimensions of the board? The board measures 90mm in length, 50mm in width, and 12.5mm in height.

16. What logic voltage do the Grove connectors use? The IO pins operate strictly on 3.3V logic. Connecting 5V logic sensors directly may damage the ESP32-S3.

17. Can I use the MicroSD card to display images on the screen? Yes. You can store UI assets like BMP or JPEG files on the SD card and use the ESP32-S3 to fetch and render them dynamically to the display, which saves your Flash memory.

18. Why use a 5V DC barrel jack instead of just USB-C? In industrial or permanent smart-home installations, a DC barrel connector provides a much more secure and robust power connection than a USB-C plug, which can easily be bumped or pulled out.

19. Are the Grove cables and external sensors included? No, the board includes the stylus and battery cable, but any Grove I2C/UART sensors or cables must be purchased separately.

20. What do the LED indicators show? There are surface-mounted LEDs near the power inputs that provide visual feedback on the battery charging status (e.g., currently charging vs. fully charged).