OSOYOO ESP32-S3 IO Breakout Board

Fig 1 – OSOYOO ESP32-S3 IO Breakout Board with an ESP32-S3 development board inserted

1. Overview

The OSOYOO ESP32-S3 IO Breakout Board is a purpose-built GPIO expansion and hardware debugging platform for the ESP32-S3 series of microcontrollers. It provides structured, labelled access to every GPIO pin, real-time LED status visualization for each pin, dual regulated power outputs, and flexible screw-terminal peripheral connections — accelerating development cycles and eliminating the messiness of a traditional breadboard setup.

The board’s 2×22P female socket accepts the vast majority of commercially available ESP32-S3 development boards. The socket span accommodates MCU modules with pin-row spacing of 0.8 / 0.9 / 1.0 inch, and all headers use the standard 2.54 mm (0.1 inch) pitch. Because the ESP32-S3 is a powerful dual-core 240 MHz processor with built-in Wi-Fi 6 and Bluetooth 5 (LE), this breakout board is the ideal foundation for ambitious IoT, robotics, and multimedia projects.

The per-pin LED status indicator system is driven by on-board 74HC04 hex inverter ICs — not by the ESP32-S3 GPIO pins directly. This means the LED indicators consume zero GPIO source current and impose no load on the MCU’s output stages, leaving GPIO performance, ADC readings, and peripheral bus (I²C / SPI / UART) signal integrity completely unaffected.

Dual JW5357MSOTB#TR DC-DC step-down converters deliver up to 5 V / 3 A and 3.3 V / 3 A simultaneously from a 7–18 V DC input. A V_Selector jumper routes either rail to the peripheral headers, so you can choose the correct logic voltage for your project without changing hardware. A protection diode between the DC-DC 5 V output and the USB 5 V path prevents back-feed current when operating on USB power alone, and an SI2302 N-channel MOSFET provides full reverse-polarity protection for the DC input.

2. Target Applications

3. Features

• ✔ ESP32-S3 Optimized Socket — 2×22P female header socket designed for ESP32-S3 development boards. Accommodates module widths of 0.8 / 0.9 / 1.0 inch at standard 2.54 mm pitch. Compatible with the majority of mainstream ESP32-S3 modules on the market.
• ✔ Per-GPIO LED Status Indicators — Every accessible GPIO pin has a dedicated LED. LED ON = pin HIGH; LED OFF = pin LOW. Verify code behavior in real time without wiring any external test components.
• ✔ Non-Intrusive 74HC04 LED Drive Circuit — LEDs are driven by on-board 74HC04 hex inverter ICs, completely decoupled from the MCU’s GPIO output stage. Zero impact on GPIO current capacity, ADC accuracy, or bus signal integrity (I²C / SPI / UART).
• ✔ Reverse Polarity Protection — SI2302 N-channel MOSFET guards against damage caused by accidental DC power polarity reversal.
• ✔ Anti-Backflow Diode — An isolation diode between the DC-DC 5 V output and the USB 5 V path prevents reverse current into the converter when operating on USB power alone.
• ✔ Dual Regulated Power Outputs — Two JW5357MSOTB#TR DC-DC step-down converters provide simultaneous 5 V / 3 A and 3.3 V / 3 A — far more current than a typical LDO regulator, capable of driving motors, servos, and LED strips.
• ✔ Selectable V Rail Voltage (3.3 V / 5 V) — The V_Selector jumper selects which regulated voltage feeds the V rail on all peripheral headers. Default is 3.3 V. Confirm before connecting any peripheral.
• ✔ Interconnected V Power Rail — All V pins on the board share a common bus, simplifying multi-peripheral wiring.
• ✔ Dual Peripheral Connection Options — Every GPIO row provides both a 2.54 mm 3-pin header (S / V / G) and a screw terminal for secure connections to sensors, servos, relays, and other peripherals.
• ✔ Wide DC Input Range — 7–18 V DC via 5.5×2.1 mm barrel jack or screw terminal. Automatic switchover between DC adapter and MCU USB power on the MCU power path.
• ✔ On-Board Power Switch & Indicator — Slide switch controls the DC-DC peripheral output. A status LED confirms the power-on state. Upload firmware via USB without cutting peripheral power.

4. Technical Specifications

5. Board Layout & Components

5.1 Top View (PCB Front)

Fig 2 – PCB top view (component side)

The board is divided into three functional zones:

• Left Zone: Left-side MCU socket pins. Each GPIO row exposes an S (signal), V (V-rail), and G (GND) 3-pin header plus a screw terminal. A column of LED indicators sits alongside the socket.
• Right Zone: Right-side MCU socket pins — mirror arrangement of the left zone with identical S / V / G headers and screw terminals per row.
• Bottom Zone (Power Section): Two DC-DC converter modules, ON/OFF slide switch, DC barrel jack, VIN screw terminal, and V_Selector jumper.

5.2 Bottom View

Fig 3 – PCB bottom view

5.3 Schematic Diagram

Fig 4 – Full schematic diagram

5.4 Component Descriptions

6. Compatible ESP32-S3 Boards

The breakout board is designed primarily for 22P-per-side (44-pin total) ESP32-S3 development boards. It is also compatible with boards that have fewer pins, provided the pin physical order matches the socket labelling. Always verify pin alignment before powering on.

7. Power Configuration

7.1 External DC Power (7–18 V) — Recommended for Full Operation

7.2 USB Power Only — Firmware Upload / GPIO Indicator Mode

When only the MCU’s USB connection is present (e.g., laptop connection for programming), the DC-DC converters are inactive. The GPIO LED indicators can still be powered from the MCU’s USB-derived supply:

7.3 V_Selector Voltage Selection

8. Getting Started – Arduino Tutorial

8.1 Arduino IDE Setup for ESP32-S3

Step 1 — Install Arduino IDE 2.x

Download and install Arduino IDE 2.x (version 2.0 or later). Arduino IDE 1.x is also supported but 2.x is recommended.

Step 2 — Add the ESP32 Board Package URL

Open File → Preferences. In the Additional boards manager URLs field, paste the following URL:

https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json

Step 3 — Install the ESP32 Package

Go to Tools → Board → Boards Manager. Search for esp32 and install esp32 by Espressif Systems (version 2.0.14 or later).

Step 4 — Select Your Board and Settings

Go to Tools → Board → ESP32 Arduino and choose the entry matching your module. For the ESP32-S3-DevKitC-1, select ESP32S3 Dev Module.

8.2 Example 1: LED Blink & GPIO Indicator Verification

This example demonstrates the breakout board’s core feature — watching the GPIO LED indicator respond to firmware in real time. No external wiring is needed beyond the USB cable.

Hardware Setup

• Seat the ESP32-S3-DevKitC-1 in the breakout board socket (align pin 1 carefully).
• Connect the USB cable from your PC to the ESP32-S3 board.
• No DC power adapter is needed for this example.
• To enable LED indicators: remove the V_Selector jumper and connect a wire from the ESP32-S3’s 3.3 V pin to any V header pin on the breakout board.

Expected Result
The LED indicator for GPIO 48 (or whichever pin you choose) blinks in sync with the digitalWrite calls. HIGH = LED ON; LOW = LED OFF.

/*
 * Example 1: LED Blink / GPIO Indicator Verification
 * Watch the breakout board LED indicator for the chosen pin toggle.
 * No external components required.
 */

const int TEST_PIN = 48;   // GPIO 48 — onboard RGB data pin on DevKitC-1
                           // Change to any GPIO you want to test

void setup() {
  delay(1000);             // Let strapping pins settle after boot
  pinMode(TEST_PIN, OUTPUT);
}

void loop() {
  digitalWrite(TEST_PIN, HIGH);   // Breakout board LED indicator: ON
  delay(500);
  digitalWrite(TEST_PIN, LOW);    // Breakout board LED indicator: OFF
  delay(500);
}

8.3 Example 2: GPIO Flowing Light

This example steps through all accessible GPIO pins sequentially, lighting each breakout board LED indicator one by one. It is the fastest way to verify every GPIO indicator is functioning and to learn the physical-to-logical pin mapping of your ESP32-S3 board.

Hardware Setup

• Seat the ESP32-S3-DevKitC-1 in the breakout board socket.
• Power via 12 V DC adapter (recommended) or USB. If USB only, follow the USB power steps in Section 7.2 to supply the indicator ICs.
• No external components needed — all LEDs are on the breakout board.

Expected Behavior

1. LEDs light up one by one at 0.2 s intervals, sequencing through all GPIO pins.
2. All LEDs remain on for 2 seconds.
3. All LEDs turn off simultaneously and stay off for 2 seconds.
4. Sequence repeats indefinitely.

Fig 5 – Hardware connection example for the flowing light demo

/*
 * Example 2: GPIO Flowing Light — ESP32-S3 IO Breakout Board
 * Sequence: light up pins one by one → all on (2 s) → all off (2 s) → repeat
 *
 * Pin list based on ESP32-S3-DevKitC-1 physical layout.
 * Left header (J1) and Right header (J3) GPIO-capable pins.
 */

const int pins[] = {
  // Left header J1 (top to bottom, GPIO pins only)
  1, 2, 42, 41, 40, 39, 38, 37, 36, 35, 0, 45, 48, 47, 21,
  // Right header J3 (top to bottom, GPIO pins only)
  4, 5, 6, 7, 15, 16, 17, 18, 8, 3, 46, 9, 10, 11, 12, 13, 14
};

const int PIN_COUNT = sizeof(pins) / sizeof(pins[0]);

void setup() {
  // Wait 1 s for strapping pins (GPIO 0, 45, 46) to finish boot tasks
  delay(1000);

  for (int i = 0; i < PIN_COUNT; i++) {
    pinMode(pins[i], OUTPUT);
    digitalWrite(pins[i], LOW);   // Start with all LEDs off
  }
}

void loop() {
  // Phase 1: Light up one by one
  for (int i = 0; i < PIN_COUNT; i++) {
    digitalWrite(pins[i], HIGH);
    delay(200);
  }

  // Phase 2: All on — hold 2 s
  delay(2000);

  // Phase 3: All off simultaneously
  for (int i = 0; i < PIN_COUNT; i++) {
    digitalWrite(pins[i], LOW);
  }

  // Phase 4: All off — hold 2 s
  delay(2000);
}

8.4 Example 3: Servo Motor Control

This example demonstrates connecting a standard RC servo to the breakout board using the S / V / G header. The servo uses the V rail for power, so set V_Selector to 5 V before connecting.

Hardware Setup

1. Set V_Selector jumper to 5 V.
2. Connect a 12 V DC adapter and switch the power switch ON.
3. Plug the servo into the GPIO 7 S / V / G header as above.
4. Upload the sketch below and open Serial Monitor at 115200 baud.

/*
 * Example 3: Servo Motor Control via S/V/G Header
 * Library required: "ESP32Servo" by Kevin Harrington
 *   Install via Arduino IDE: Tools -> Manage Libraries -> search "ESP32Servo"
 *
 * Wiring: servo signal -> GPIO 7 S header, servo VCC -> V (5V), servo GND -> G
 */

#include 

Servo myServo;
const int SERVO_PIN = 7;

void setup() {
  Serial.begin(115200);
  delay(1000);
  myServo.attach(SERVO_PIN, 500, 2400);  // Min/max pulse width in microseconds
  Serial.println("Servo initialized.");
}

void loop() {
  Serial.println("Moving to 0 deg");
  myServo.write(0);
  delay(1000);

  Serial.println("Moving to 90 deg");
  myServo.write(90);
  delay(1000);

  Serial.println("Moving to 180 deg");
  myServo.write(180);
  delay(1000);
}

9. Important Notes

• Verify Pin Alignment Before Powering On: The physical pin order of your ESP32-S3 board must match the breakout board’s socket silkscreen. Inserting a board with a different pin arrangement can short VCC directly to GPIO pins. When using a non-recommended board, verify with a multimeter before applying power.
• Floating GPIO Pins — LED Flicker: A GPIO in floating / high-impedance state (input mode without pullup or pulldown) may cause its LED indicator to glow dimly or flicker. Always define a pin mode in your sketch using pinMode() with OUTPUT, INPUT_PULLUP, or INPUT_PULLDOWN.
• ESP32-S3 Strapping Pins (GPIO 0, 45, 46): These pins influence boot mode during reset. Always include a startup delay(1000) in setup() before driving these pins as outputs.
• V Rail is Fully Interconnected: All V-rail pins on the board share a single common bus. Do not connect power sources of different voltages to different V pins — this creates a short circuit.
• Confirm V_Selector Voltage Before Connecting Peripherals: Applying 5 V to a 3.3 V-only device will permanently damage it. Check the jumper position every time before adding new hardware.
• Maximum DC Input Voltage: Do not exceed 18 V on the VIN input. Higher voltages can damage the DC-DC converters and other board components.
• Minimum DC Input Voltage: A minimum of 7 V is required for the DC-DC converters to regulate correctly. Input below 7 V will result in unstable or insufficient output voltage.
• Per-Rail Current Limit: Each DC-DC converter is rated at 3 A maximum. Ensure the total current draw of all peripherals connected to a given rail does not exceed this limit.
• USB-Only Mode: When operating from USB power alone, remove the V_Selector jumper to prevent any back-feed into the DC-DC converters. The built-in diode already protects the 5 V path; removing the jumper additionally protects the 3.3 V path.
• LED Indicator Behavior Summary:
  

  GPIO State	LED Indicator
  Output HIGH	LED ON (solid)
  Output LOW	LED OFF
  Floating / High-Z (no pullup/down)	May glow dimly or flicker
  Input with internal pull-up	LED ON
  Input with internal pull-down	LED OFF

10. Mechanical Information

Fig 6 – PCB outline (see production drawing for exact dimensions)

11. Related Documents

OSOYOO Related Products

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