ESP32 Hardware
ESP32 DevKit V1 Pinout and Wiring Guide
The ESP32 DevKit V1 is a widely used development board based on the ESP32 microcontroller, known for its built-in Wi-Fi and Bluetooth capabilities. It’s popular for IoT projects due to its versatility and rich set of features. This guide will help you understand the ESP32 DevKit V1 pinout and Wiring Guide how to wire it for different applications, making it suitable for both beginners and experienced users.
ESP32 DevKit V1 Pinout Diagram
Below is a labeled diagram of the ESP32 DevKit V1 showing the functions of all pins:
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ESP32 DevKit V1 Pinout Overview
The ESP32 DevKit V1 features 38 pins with various functions, including power, GPIO, analog inputs, and communication protocols (I2C, SPI, UART). Here’s a detailed overview:
| Pin Name | GPIO Number | Function | Description |
| 3V3 | – | Power Supply | Provides 3.3V power for the board and connected components. |
| GND | – | Ground | Common ground connection for the board and peripherals. |
| VIN | – | Power Input | Accepts 5V to power the board (alternative to USB power). |
| GPIO0 | 0 | Boot Mode / I/O | Used to enter programming mode when pulled low. |
| GPIO1 | 1 | UART TX | Transmit pin for serial communication. |
| GPIO2 | 2 | I/O | Can control the onboard LED; often used as an output pin. |
| GPIO3 | 3 | UART RX | Receive pin for serial communication. |
| GPIO4 | 4 | I/O / Touch Sensor | Supports touch sensing and can be used as a general-purpose pin. |
| GPIO5 | 5 | I/O / SPI SS | Often used as an SPI chip select pin. |
| GPIO12 | 12 | I/O / ADC / Touch Sensor | Supports analog input, digital I/O, and touch sensing. |
| GPIO13 | 13 | I/O / ADC / Touch Sensor | Supports analog input, digital I/O, and touch sensing. |
| GPIO14 | 14 | I/O / ADC | Can be used as an analog input or for digital I/O. |
| GPIO15 | 15 | I/O / Touch Sensor | Can be used for touch sensing. |
| GPIO16 | 16 | I/O | General-purpose I/O. |
| GPIO17 | 17 | I/O | General-purpose I/O. |
| GPIO18 | 18 | SPI SCK | Serial clock line for SPI communication. |
| GPIO19 | 19 | SPI MISO | Master In Slave Out for SPI communication. |
| GPIO21 | 21 | I2C SDA | Data line for I2C communication. |
| GPIO22 | 22 | I2C SCL | Clock line for I2C communication. |
| GPIO23 | 23 | SPI MOSI | Master Out Slave In for SPI communication. |
| GPIO25 | 25 | I/O / ADC / DAC | Can be used as an analog input or DAC output. |
| GPIO26 | 26 | I/O / ADC / DAC | Supports analog input and DAC output. |
| GPIO27 | 27 | I/O / ADC / Touch Sensor | Can be used for analog input or touch sensing. |
| GPIO32 | 32 | ADC / Touch Sensor | Analog input and touch sensing capabilities. |
| GPIO33 | 33 | ADC / Touch Sensor | Supports analog input and touch sensing. |
| GPIO34-39 | 34-39 | ADC (Input Only) | Can only be used for analog input readings. |
| EN | – | Enable | Enables the chip when pulled high. |
| BOOT | – | Boot Mode | Used to place the ESP32 in flashing mode during code upload. |
Powering the ESP32 DevKit V1
The board can be powered in several ways:
- Via USB Cable: Plug the micro USB cable into the board to connect it to your computer or a USB power adapter.
- VIN Pin (5V): The VIN pin can be connected to a 5V power source, such as a battery pack.
- 3V3 Pin (3.3V): Provides a 3.3V output, which can also be used to power external components.
Note: Avoid powering the board with a voltage higher than 5V to prevent damage.
Digital I/O (GPIO) Usage
Controlling LEDs
- Connect the LED’s anode to a GPIO pin (e.g., GPIO2).
- Connect the cathode to GND through a resistor (220 ohms recommended).
Reading Button States
- Connect one side of the button to a GPIO pin (e.g., GPIO16).
- Connect the other side to GND.
- Enable internal pull-up in the code to avoid floating states.
Using Touch-Sensitive Pins
- The ESP32 has built-in touch sensors on several GPIO pins (e.g., GPIO4, GPIO27).
- These can detect capacitance changes to register touch inputs.
Analog Input (ADC) Usage
The ESP32 DevKit V1 supports analog inputs via its ADC (Analog to Digital Converter) channels, allowing you to read sensor data from 0V to 3.3V.
Connecting Analog Sensors
- Power the sensor with 3.3V and GND.
- Connect the sensor’s output to an ADC-compatible GPIO pin (e.g., GPIO36).
Adjusting ADC Resolution
- The default resolution is 12 bits (0-4095), but it can be adjusted in the code to 9, 10, or 11 bits for specific applications.
Tip: Avoid using ADC2 pins when the ESP32’s Wi-Fi is active, as they share internal resources.
Setting Up I2C Communication
The I2C protocol uses two lines, SDA and SCL, for communicating with peripherals like displays and sensors.
- SDA (Data Line): Connect to GPIO21.
- SCL (Clock Line): Connect to GPIO22.
Recommendation: Use pull-up resistors (typically 4.7kΩ) on SDA and SCL lines for stable communication.
Setting Up SPI Communication
The SPI protocol allows for fast data transfer with devices like SD cards and displays.
- SCK (Clock): Connect to GPIO18.
- MISO (Data In): Connect to GPIO19.
- MOSI (Data Out): Connect to GPIO23.
- SS (Chip Select): Connect to GPIO5.
Note: Use level shifters if interfacing with 5V devices to avoid damaging the board.
Troubleshooting Common Issues
1. ESP32 Not Powering On
- Make sure you are using a reliable USB cable or 5V power source.
- Verify the connections on the VIN or 3V3 pins.
2. Code Upload Issues
- Press and hold the BOOT button while uploading code.
- Confirm the correct COM port is selected in the IDE.
3. Wi-Fi Connection Problems
- Double-check the Wi-Fi SSID and password.
- Move the ESP32 closer to the Wi-Fi router for a stronger signal.
4. Unstable Analog Readings
- Add a capacitor (10μF) across the ADC input to filter noise.
- Avoid using ADC2 channels while Wi-Fi is active.
Frequently Asked Questions
1. What is the ESP32 DevKit V1 pinout?
- The ESP32 DevKit V1 pinout is the layout of the board’s 38 pins, including power, I/O, analog, and communication pins.
2. Can the ESP32 handle 5V signals?
- No, the GPIO pins are 3.3V tolerant. Use level shifters if interfacing with 5V logic devices.
3. How can I power the ESP32 DevKit V1?
- It can be powered via USB, the VIN pin (5V), or the 3V3 pin (3.3V).
Conclusion: ESP32 DevKit V1 Pinout and Wiring Guide
This ESP32 DevKit V1 pinout and wiring guide offers essential information to help you understand and use the board’s pins. By following the steps outlined here, you can get started with your own IoT projects, whether you are controlling LEDs, reading sensors, or setting up communication protocols like I2C and SPI.