Arduino PCB Design
Worked for 4 mins 1 sec
Aviso de diseño: el Arduino Nano no tiene suficientes GPIO para 3×A4988, HX711, SPI SD, I2C, 7 Hall, IR y teclado 4x4 todos directos; cablearé el núcleo funcional y dejaré visible la limitación para corregir luego con expansores I/O o un MCU mayor.
Worked for 3 mins 31 sec
Me quedé bloqueado porque tu cuenta no tiene ACUs disponibles, así que no puedo seguir ejecutando cambios ahora mismo.
He avanzado lo siguiente:
- Renombré el proyecto a Controlador Dosificador Arduino y añadí una descripción.
- Creé el archivo Project Specification con la arquitectura del sistema.
- Añadí Arduino Nano, HX711, 3× A4988, DS3231, LM7805, fusible PTC, conectores, capacitores y resistencias pull-up.
- Organicé el esquemático en bloques.
- Cableé alimentación principal: 12V, 5V_REG, 5V y GND.
- Cableé salidas de motores y señales STEP/DIR/ENABLE de los tres A4988 al Arduino.
Pendiente cuando tengas ACUs:
- Cablear HX711, RTC/I2C, SD/SPI, IR, Hall y keypad.
- Resolver la limitación importante: el Arduino Nano no tiene suficientes GPIO para todo directo; probablemente conviene añadir expansores I/O o cambiar a un MCU con más pines.
- Ejecutar revisión ERC y corregir pines flotantes.
- Pasar luego a layout PCB.
Añadir expansor I/O
Cambiar a Mega
Revisar pines faltantes
Cablear periféricos
Comprobar ERC
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Project Specification
Project Overview
- Status: Draft
- Device: Arduino Nano based controller PCB for a dosing/dispensing mechanism.
- Purpose: Central board for weight sensing, timekeeping, local UI, data logging, position sensing, and three stepper motor drivers.
Intended Use
- Prototype control board powered from a 12 VDC external supply.
- Intended for a dosing machine using NEMA 17 stepper motors, a 1 kg load cell, Hall sensors, an IR presence sensor, LCD display, SD logging, and keypad input.
What the Device Should Do
- Read weight through an HX711 load-cell module.
- Drive three stepper motors through A4988 carrier modules.
- Read 7 Hall/position sensors and one IR input sensor.
- Communicate with an RTC DS3231 and LCD module over I2C.
- Communicate with an SD-card module over SPI.
- Read a 4x4 keypad matrix.
Main Features
- 12 V input terminal for motor power and regulator input.
- 5 V logic rail from an LM7805 linear regulator.
- Arduino Nano V3.0 socket/header interface.
- Three A4988 driver sockets with bulk capacitors on VMOT.
- External connectors for motors, sensors, LCD, SD module, keypad, and load cell.
System Architecture
Diagram
Hardware Subsystems
- Power: 12 VDC input, 5 V LM7805 logic rail, shared ground.
- Compute: Arduino Nano V3.0 / ATmega328P module.
- Motor Control: Three A4988 stepper-driver carrier sockets.
- Sensing: HX711 load-cell module, Hall sensor connector, IR sensor connector.
- User Interface: I2C LCD connector and 4x4 keypad connector.
- Storage/Time: SD card SPI connector and DS3231 RTC I2C module.
Interfaces and Connections
- J1: 12 VDC input, 2-pin screw terminal.
- J2: Load cell, 4-pin terminal: E+, E-, A+, A-.
- J3-J5: Stepper motor outputs, 4-pin: 1B, 1A, 2A, 2B.
- J6: Hall sensors: H1-H7 plus 5 V/GND.
- J7: IR sensor: 5 V/GND/OUT.
- J8: LCD I2C: 5 V/GND/SDA/SCL.
- J9: SD module SPI: 5 V/GND/MISO/MOSI/SCK/CS.
- J10: 4x4 keypad matrix, 8 GPIO lines.
Power and Runtime Expectations
- External supply assumed: 12 VDC, 5 A.
- Motors use 12 V VMOT through A4988 modules.
- Logic peripherals use 5 V from LM7805.
Power Tree and Power Budget
- Initial assumption: 5 V logic load may approach several hundred mA depending on LCD, SD, modules, and sensors.
- LM7805 thermal dissipation is a risk from 12 V input: P = (12 V - 5 V) × I_logic. At 300 mA this is 2.1 W and requires significant heatsinking; a buck regulator is recommended for production reliability.
Manufacturing and Assembly Expectations
- Through-hole headers/terminals preferred for module sockets and external wiring.
- Prototype-style board using socketed Arduino Nano and A4988 modules.
Firmware-Relevant Hardware Requirements
- Arduino-style pin mapping is required for I2C, SPI, A4988 STEP/DIR/EN, sensor inputs, and keypad matrix.
- Firmware should configure sensor inputs with pull-ups where needed.
Physical Design Expectations
- Layout should place power input/regulator at top/edge, Arduino centrally, A4988 drivers near motor connectors, and sensor/UI connectors along board edges.
Important Design Decisions
- Build uses module sockets rather than bare IC implementations for Arduino Nano, HX711, DS3231, SD, LCD backpack, and A4988 drivers.
- Keep 12 V motor power separate from 5 V logic except for common ground.
Assumptions
- Arduino Nano operates at 5 V logic.
- SD card connector is for an external SD module that handles 3.3 V regulation/level shifting; a raw microSD socket would need level shifting and 3.3 V regulation.
- Hall sensors are A3144/open-collector style and need pull-ups.
- Exact Arduino GPIO assignment was not supplied, so a reasonable Arduino Nano pin map will be used.
Change Notes
- Created from the user-provided Spanish PCB layout/component list.
Project Overview
Intended Use
What the Device Should Do
Main Features
System Architecture
Hardware Subsystems
Interfaces and Connections
Power and Runtime Expectations
Power Tree and Power Budget
Manufacturing and Assembly Expectations
Firmware-Relevant Hardware Requirements
Physical Design Expectations
Important Design Decisions
Assumptions
Change Notes
