This project involves designing a complete schematic for a robotic arm controller based on the ESP32-C3 microcontroller, specifically using the ESP32-C3-MINI-1-N4 module. The design features a dual power input system and comprehensive power management, motor control, I/O interfaces, and status indicators—all implemented on a 2-layer PCB.
Key Specifications:
Microcontroller:
• ESP32-C3-MINI-1-N4 module operating at 3.3V.
• Integrated USB programming connections with reset and boot mode buttons.
Power System:
• Dual power inputs with automatic source selection: USB-C port (5V input) and barrel jack (6-12V input).
• Power management using LM74610 smart diode controllers for power source OR-ing.
• AMS1117-3.3 voltage regulator to deliver a stable 3.3V supply to the microcontroller.
• Filter capacitors (10μF electrolytic and 100nF ceramic) at the input and output of the regulators.
• Protection features including USBLC6-2SC6 for USB ESD protection and TVS diodes for barrel jack overvoltage protection.
Motor Control:
• Incorporates an Omron G5LE relay with a PC817 optocoupler and BC547 transistor driver.
• Provides dedicated header pins for servo motors with PWM outputs.
• Flyback diode protection implemented for relay safety.
I/O Connections:
• Header pins exposing ESP32-C3 GPIOs: Digital I/O (IO0-IO10, IO18, IO19) and serial communication lines (TXD0, RXD0), plus an enable pin.
• Each I/O pin includes appropriate 10kΩ pull-up/pull-down resistors to ensure reliable performance.
Status Indicators:
• A power status LED with a current-limiting resistor.
• A user-controllable LED connected to one of the GPIO pins.
PCB Layout Requirements:
• 2-layer PCB design with separate ground planes for digital and power sections.
• Placement of decoupling capacitors close to power pins to reduce noise.
• Adequate trace width for power lines to ensure efficient current flow.
• Inclusion of mounting holes at the board corners for secure installation.
• All components are properly labeled with correct values for resistors, capacitors, and other passive elements, following standard design practices for noise reduction, stability, and reliability.
