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Pinout¤

MCU pin usage¤

Function ESP32-S3 pin Notes
Status LED IO46 Simple digital output
Onboard RGB LED chain IO48 WS2812B data line
External RGB strip connector IO36 Separate WS2812B data line
Left button IO2 Digital input
Right button IO0 Digital input
Servo output 1 IO21 50 Hz PWM-capable output
Servo output 2 IO38 Often used for the pen lifter
Reflectance ADC 1 IO4 Shared by A1 or B1
Reflectance ADC 2 IO5 Shared by A2 or B2
Reflectance ADC 3 IO6 Shared by A3 or B3
Reflectance ADC 4 IO7 Shared by A4 or B4
Reflectance bank select IO8 1 = A bank, 0 = B bank
Reflectance IR emitter enable IO47 1 = emitters on
Left motor driver A IO11 PWM / H-bridge control
Left motor driver B IO12 PWM / H-bridge control
Right motor driver A IO45 PWM / H-bridge control
Right motor driver B IO13 PWM / H-bridge control
Left encoder A IO40 Digital input
Left encoder B IO39 Digital input
Right encoder A IO41 Digital input
Right encoder B IO42 Digital input
Shared I2C SDA IO10 Onboard and external smart sensors
Shared I2C SCL IO3 Onboard and external smart sensors

Reflectance sensor mapping¤

The eight bottom sensors share four ADC inputs through multiplexing:

ADC input Front / line bank Rear / wheel bank
IO4 A1 B1
IO5 A2 B2
IO6 A3 B3
IO7 A4 B4

Used names:

  • front line sensors: LineFL, LineFR, LineBL, LineBR
  • wheel sensors: WheelFL, WheelFR, WheelBL, WheelBR

External connectors¤

I2C connectors¤

The shared I2C bus is available on connectors marked I2C.

  • SDA = IO10
  • SCL = IO3
  • the connector also provides power and ground

Use:

  • optional VL53L0X distance sensor
  • optional external RGB / color sensor

External LED strip connector¤

Signals:

  • data on IO36
  • power from the board
  • ground

The interface is intended for WS2812B-compatible LEDs.

Servo connectors¤

The board provides two 3-pin servo connectors:

  • Servo1 = IO21
  • Servo2 = IO38

Servo2 is commonly used for the pen lifter.

Simple I/O connectors¤

Simple 3-pin connectors with signal, power, and ground are also available:

  • VCC
  • GND
  • signal

Example: an external button can be connected to IO1, VCC, and GND.