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LITTLE WEB SERVER SCHEMATIC

ESP32-S3 Super Mini + GC9A01 Display + Charging Module

LITTLEFS VERSION TF CARD VERSION NEW
GC9A01 1.28 inch Round LCD Display

GC9A01 ROUND LCD

1.28" 240x240 SPI Display

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ESP32-S3 Super Mini

ESP32-S3 SUPER MINI

Main Microcontroller

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TP4056 Charging Module

TP4056 CHARGER

USB-C LiPo Charging Module

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18650 Batteries

18650 BATTERIES (x2)

3.7V Rechargeable LiPo

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1mm Brass Wire

1MM BRASS WIRE

For Wiring Connections

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3mm Copper Banding

3MM COPPER BANDING

Flexible Copper Strip

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2.5mm Screws

2.5MM SCREWS

Enclosure Assembly

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ESP32-S3 Super Mini USB-C TX RX 1 2 3 4 5 6 7 5V GND 3.3V 13 12 11 10 9 8 GC9A01 Display GND VCC SCL SDA RES DC CS BLK 240x240 TP4056 Charger USB-C OUT+ B+ B- OUT- 18650 Batteries (x2) (Parallel) 3.7V + - 3.7V SWITCH OUT IN 5V IN Wire Colors 5V Power Ground SCK (G12) MOSI (G11) RES (G10) DC (G9)

PIN CONNECTIONS

COMPONENT COMPONENT PIN ESP32-S3 PIN WIRE COLOR
GC9A01 Display VCC 3V3 Red
GND GND Black
SCL/SCLK GPIO 12 Yellow
SDA/MOSI GPIO 11 Cyan
RST GPIO 10 Purple
DC GPIO 9 Orange
CS GPIO 8 Green
BL (Backlight) GPIO 7 White
TP4056 Charger OUT+ ESP32 5V Red
OUT- ESP32 GND Black
B+ Battery (+) Red
B- Power Switch OUT Black
Power Switch IN Battery (-) Black
OUT TP4056 B- Black
18650 Batteries (x2) Positive (+) [Parallel] TP4056 B+ Red
Negative (-) [Parallel] Power Switch IN Black

IMPORTANT NOTES

  • Display: Uses software SPI. No MISO connection needed (write-only).
  • Backlight: GPIO 7 controls display brightness. Set HIGH to turn on.
  • 5V Input: The TP4056 OUT+ provides ~4.2V (fully charged) to ~3.0V (discharged) from the batteries. This connects to the ESP32's 5V pin, which feeds the onboard voltage regulator. Despite the name "5V", the ESP32-S3 accepts 4.0-6.0V on this pin.
  • 3.3V Output: The ESP32's internal LDO regulator converts the 5V input down to 3.3V. This 3.3V rail powers all external components (display). Never connect 5V directly to components - they require 3.3V!
  • Power Switch: Located on the battery NEGATIVE rail between the 18650s and TP4056 B- pin. Placing the switch on the negative rail is safer - it completely isolates the batteries when OFF, preventing any current flow. Turn OFF before connecting USB to charge safely, as this prevents back-feeding the batteries during charging.
  • Batteries: Two 18650 cells wired in PARALLEL (3.7V nominal, doubled capacity). Connect to TP4056 B+ and B- pins.
  • Charging: TP4056 charges batteries via USB-C. Red LED = charging, Green LED = full.
  • Ground: All GND pins connect to common ground rail (ESP32 GND, display GND).
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