Autonomous Pepper Harvesting Robot Design
Thought for 1 min 13 sec
Stopped because the project has no available ACUs, so I can’t continue executing changes right now.
Completed so far:
- Inspected the existing schematic and found the ESP32 DevKitC, XL1509-5.0 buck regulator, 5A fuse, 12V/5V/3V3 rails, motor/sensor blocks, and existing nets already present.
- Checked datasheet guidance for:
- ESP32 DevKitC power/header pins.
- XL1509-5.0 recommended 12V-to-5V/2A application circuit.
- Existing 5A fuse rating.
- Added these Part 1 components:
- J1: 12V battery input screw terminal.
- J2: external normally-closed E-stop connector.
- D4: 10A/40V Schottky reverse-polarity protection diode.
- D5: 1N5820 XL1509 buck catch diode.
- L1: 68uH / 2A buck inductor.
- LED16: green Ready LED.
- LED17: yellow Harvesting LED.
- LED18: red Fault LED.
Not completed yet:
- The generic resistors/capacitors for LED current limiting, E-stop pull-up, buck input/output capacitors, and decoupling were attempted but not added because the generic part lookup failed.
- The newly added components are not wired yet.
- Project files for the power distribution diagram, pin table, BOM, and PCB recommendations still need to be created/updated.
- Schematic checks still need to be rerun and fixed after wiring.
Next work once ACUs are available:
- Add the missing resistors and capacitors correctly.
- Wire battery → fuse → reverse-polarity protection → 12V rail → XL1509 → 5V_SYS.
- Wire common ground, E-stop NC input, and three ESP32-driven status LEDs.
- Update documentation files and rerun checks.
Add missing passives
Show power wiring
Create docs
Run checks later
Refine this doc
Ask about this doc
Project Specification — Pepper Harvesting Robot Controller
Project Overview
Draft electrical control system for an autonomous black pepper harvesting robot using an ESP32 DevKit main controller and ESP32-CAM vision module.
Intended Use
College prototype for a robot that climbs or moves vertically along guide rails, rotates a harvesting ring around a pepper vine/tree, detects ripe bunches, extends an arm, cuts bunches, and returns home.
Main Features
- ESP32 DevKit main state-machine controller.
- ESP32-CAM target detection over UART.
- Two A4988/A498x stepper channels for vertical carriage and ring rotation.
- PCA9685 I2C PWM driver for MG996R arm-extension and scissor servos.
- HC-SR04 ultrasonic distance input, MPU6050 IMU on I2C, upper/lower limit switches, LEDs, and NC E-stop motor-enable chain.
System Architecture
Diagram
Power Tree and Budget
- 12V rail: A4988 motor VMOT inputs, NEMA17 coils, buck input.
- 5V rail: ESP32 DevKit 5V input, ESP32-CAM, PCA9685 board logic/V+, HC-SR04, MPU6050 breakout, LEDs, MG996R servos.
- Estimated peaks: ESP32 300-500mA bursts, ESP32-CAM 310mA with flash, PCA9685 <10mA logic, HC-SR04 ~15mA, MPU6050 <5mA, two MG996R servos can exceed 2A each under stall, steppers depend on current limit. Use a separate 5-6V BEC rated at least 5A for servos in real hardware; XL1509 2A is acceptable only for logic plus light prototype servo testing.
Key Assumptions
- ESP32 DevKit board is powered via its 5V header from the protected 5V rail, not simultaneously by USB power.
- A4983 library ICs are used as schematic placeholders for A4988-style carrier wiring; prototype should use A4988 carrier modules with onboard sense resistors and current-limit potentiometers.
- HC-SR04 ECHO must be level-shifted or divided to 3.3V before entering ESP32.
- All grounds are common, with motor currents returned separately to the battery/star ground area.
Success Criteria
- All control nets mapped for firmware.
- Protection, fusing, bulk capacitance, decoupling, and E-stop strategy documented.
- Ready for Tinkercad reconstruction and PCB-layout planning after review.
Project Overview
Intended Use
Main Features
System Architecture
Power Tree and Budget
Key Assumptions
Success Criteria
