Pocket sprite

POCKET_SPRITE

A custom ESP32-S3 handheld game console with joystick input, an action button, ST7735 color TFT display, buzzer audio, battery power, custom PCB artwork, and multiple built-in mini games.

POCKET_SPRITE is a compact original hardware project built around the Seeed Studio XIAO ESP32-S3 and a 1.8-inch ST7735 SPI TFT display. The board combines custom electronics, embedded firmware, pixel graphics, playful silkscreen art, and portable battery-powered hardware into a small handheld game device.

Project Status

In progress. Breadboard input/display testing completed before the PCB version. Current hardware direction uses the XIAO ESP32-S3, joystick, 1.8-inch SPI TFT, A button, TFT backlight control, buzzer output, battery input through the XIAO BAT pads, and a switched 3.3V rail for game hardware.

Features

• Seeed Studio XIAO ESP32-S3
• 1.8-inch ST7735 SPI TFT display
• Joystick input
• One action button
• TFT backlight control
• Buzzer output
• Battery input through the XIAO battery pads
• Switched 3.3V rail for game hardware
• Custom PCB outline
• Custom silkscreen artwork
• LovyanGFX display driver
• Multiple built-in games and modes

Games / Modes

Current firmware includes:

• Adventure: small character-based adventure game
• Pocket Pet: virtual pet room with movement, jumping, ball pushing, and ball kicking
• Dress Up: character creator with selectable gender, hairstyles, colors, outfits, shoes, and a small playable character
• BM Tron: light-cycle style trail game
• Snake: classic snake mini game

Hardware

Pin Map

Joystick Calibration

Breadboard joystick values measured during testing:

Firmware should use calibration/deadzone handling instead of assuming perfect center values.

Display Interface

The display is a 1.8-inch ST7735 SPI TFT.

TFT CS    → D4
TFT DC    → D5
TFT RESET → D6
TFT BL    → D7 / B-LITE
TFT SCK   → D8
TFT MOSI  → D10

Controls

Joystick SW → D0
Joystick X  → D1
Joystick Y  → D2
A button    → D3

The joystick direction mapping from breadboard testing:

UP    → X low
DOWN  → X high
LEFT  → Y high
RIGHT → Y low

Audio Output

The buzzer output is labeled CHIRP and is driven from D9.

D9 / CHIRP → buzzer drive

If the buzzer current is above the safe GPIO drive range, use a transistor or MOSFET driver instead of driving the buzzer directly from the XIAO GPIO.

Power Design

The battery connects directly to the XIAO battery pads. The XIAO provides the regulated 3.3V rail used by the game hardware.

Battery → XIAO BAT pads
XIAO_3V3 → switch → +3V3_SW
+3V3_SW → joystick / display / buzzer support hardware

Battery support should follow the Seeed Studio XIAO ESP32-S3 battery/BAT pad guidance for a 1S LiPo setup.

Firmware Direction

Useful firmware modules:

• Joystick calibration
• Direction/deadzone handling
• A button input
• LovyanGFX display setup
• ST7735 display drawing helpers
• Sprite drawing and animation loop
• Game state/menu system
• Buzzer tone/beep helper
• Backlight control
• Battery-aware sleep or low-power behavior later

Bring-Up Checklist

1. Confirm XIAO ESP32-S3 orientation and soldering.
2. Verify XIAO_3V3 and +3V3_SW behavior.
3. Test joystick X/Y ADC values.
4. Test joystick switch.
5. Test A button.
6. Test TFT display init over SPI.
7. Test TFT CS/DC/RESET behavior.
8. Test TFT backlight control on B-LITE.
9. Test buzzer output on CHIRP.
10. Run joystick-controlled movement demo.
11. Run each game mode.
12. Add battery testing only after USB-powered bring-up is stable.

Design Notes

• Keep TFT SPI traces clean and reasonably short.
• Keep joystick analog lines away from buzzer switching where practical.
• Leave room for finger access around the joystick and A button.
• Keep silkscreen labels readable around controls.
• Treat joystick calibration as firmware data, not fixed ideal values.
• Keep the board small enough to feel handheld, not like a dinner plate with pixels.

Repository Output Images

Expected image paths for GitHub README rendering:

Outputs/
  IMG/
    3D-T.png
    3D-B.png
    SCHEMATIC.png
    L1-SIG.png
    L2-GND.png

Safety / Design Note

POCKET_SPRITE is a low-voltage handheld electronics project. Verify battery polarity, switched power behavior, buzzer drive current, and display wiring before portable use.

Designed & Engineered by Brandon Shelly