Understanding the ESP32 Pinout
The standard 30-pin ESP32 Development Board is incredibly powerful, but its pinout can be confusing for beginners because many pins have multiple functions. Here is what you need to know.
Analog Pins (ADC)
The ESP32 has two 12-bit ADC channels. However, ADC2 pins cannot be used when Wi-Fi is active! Therefore, always stick to ADC1 pins (GPIO 32, 33, 34, 35, 36, 39) for reading analog sensors like potentiometers.
Strapping Pins (Avoid These)
There are certain pins (GPIO 0, 2, 5, 12, and 15) known as strapping pins. These determine the boot mode of the ESP32. Do not connect relays or pull-ups to these pins during boot, or your ESP32 will fail to turn on.
Digital Only / Input Only
Remember that GPIOs 34, 35, 36, and 39 are INPUT ONLY. You cannot use them to output a signal to an LED or motor.
