Motherboard

🖥️ D1 R32

📌 Simple Description

The D1 R32 is the “brain” of our projects. It’s a small board that controls everything we connect: sensors, motors, lights, and screens.

⚡ What makes it special

It has Wi-Fi and Bluetooth, so it can connect wirelessly.
It’s easily programmed from a computer using a USB cable.
It’s compatible with Arduino, which means we can use it with many pre-made examples and projects.

🎯 Use in the course

With this board we will:

Give instructions to robots to move or react.
Connect sensors that detect the world (light, distance, temperature).
Send data and receive commands from a computer or even a cell phone.

👉 Think of the D1 R32 as the brain of the robot: it receives information, makes decisions, and controls the other parts.

Technical specifications

Microcontrollers	D1 R32 (ESP32)
Operating voltage	3.3V
Input Voltage (Recommended)	6-9V (DC)
Number pins	20
Download the interface	USB Type-Micro
Wireless transmission protocol	WiFi 802.11 b/g/n
Bluetooth standard	4.2BR/EDR/BLE standard
Chip clock frequency	240MHz
Expand Flash	4MB
SRAM	520KB
Built-in ROM	448KB

Pin Mappings

Complete pinout and GPIO mapping for D1 R32

Arduino Label	ESP32 GPIO	Function / Interface	Notes / Remarks
A0	GPIO2	ADC_LINE(0), LED, PWM_DEV(0):	Shared with onboard LED; also usable as analog input.
A1	GPIO4	ADC_LINE(1)	ADC channel.
A2	GPIO35	ADC_LINE(2)	ADC channel; input-only.
A3	GPIO34	ADC_LINE(3)	ADC channel; input-only.
A4	GPIO36	ADC_LINE(4)	ADC channel; input-only.
A5	GPIO39	ADC_LINE(5)	ADC channel; input-only.
D0 (RX)	GPIO3	UART_DEV(0):RxD	Serial RX (connected to USB-serial bridge).
D1 (TX)	GPIO1	UART_DEV(0):TxD	Serial TX (connected to USB-serial bridge).
D2	GPIO26	DAC_LINE(1), PWM_DEV(0):1	DAC output & PWM capable.
D3	GPIO25	DAC_LINE(0), PWM_DEV(0):0	DAC output & PWM capable. (D3 → GPIO25 — verified mapping.)
D4	GPIO17	UART_DEV(1):TxD	Secondary UART TX — may be unavailable on some modules (flash pins).
D5	GPIO16	UART_DEV(1):RxD / PWM_DEV(0):1	Depends on revision; GPIO9–10 are often flash pins and may be unavailable. Verify your board.
D6	GPIO27	PWM_DEV(0):2	PWM capable.
D7	GPIO14	PWM_DEV(0):3	PWM capable.
D8	GPIO12	PWM_DEV(0):3	PWM capable.
D9	GPIO13	PWM_DEV(0):3	PWM capable.
D10	GPIO5	SPI_DEV(0):CS0, PWM_DEV(1):0	SPI chip-select / PWM output.
D11	GPIO23	SPI_DEV(0):MOSI, PWM_DEV(1):1	SPI MOSI / PWM output.
D12	GPIO19	SPI_DEV(0):MISO	SPI MISO.
D13	GPIO18	SPI_DEV(0):CLK	SPI clock.
SDA	GPIO21	I2C_DEV(0):SDA	I²C data (default bus).
SCL	GPIO22	I2C_DEV(0):SCL	I²C clock (default bus).
LED_BUILTIN	GPIO2	LED / PWM_DEV(0):4	Onboard LED (same as A0 on many revisions).

Notes: ADC = analog input (input-only pins: GPIO34/35/36/39), DAC = ESP32 DAC outputs, PWM = LEDC PWM channels, SPI/I²C/UART are default bus assignments. GPIO9/10 are often used by flash on some modules — treat as verify on your board.