📝 Handwriting Robot Diagnostic Report & README

📦 Overview

This document provides a comprehensive summary of a handwriting robot machine purchased from Alibaba/Aliexpress that has never functioned correctly, despite extensive troubleshooting and communication with the vendor. The machine has been disassembled, rewired, and rebuilt multiple times, but the core issues persist.

Attached are videos, images, and descriptions to assist in evaluating and potentially resolving the machine's problems.

🔧 Machine Description

• Device: DIY Handwriting/Plotter Robot
• Status: Fully assembled and tested (multiple times). Unable to perform any handwriting tasks successfully.

❗️Main Issues Encountered

1. Z-Axis Nonfunctional
   The Z-axis motor does not respond or move.
   
   • No motion or writing attempts that show pen up/down mechanics.
   • May be related to:
     • Faulty stepper motor or driver.
     • Incorrect pin assignment or firmware config.
     • Power delivery issues.
2. X and Y Axis Malfunction
   X and Y motors power up but exhibit erratic or limited movement.
   
   • Inconsistent or jittery motion when trying test files.
   • Suggests:
     • Improper calibration.
     • Motor wiring reversed.
     • Timing pulleys slipping or loose (see vendor response).
3. No Successful Output
   After months of attempts, the machine has not written a single word.
   
   • Tested with included sample files from the vendor.

🎥 Video Documentation

• Test Attempt Timelapse: Watch Video
  Demonstrates the robot attempting to follow a sample file. Movement is not coordinated, and no legible writing is produced.
• Axis Testing & Button Presses: Watch Video
  User narrates actions while testing individual axes and observing the response. Clear footage of wiring, button pressing, and machine movement.

🛠️ Troubleshooting Already Performed

• ✅ Rewired all motors and connectors from scratch.
• ✅ Disassembled and reassembled full frame and motor system.
• ✅ Verified correct voltage from power supply.
• ✅ Cross-checked motor connections against vendor’s documentation.
• ✅ Attempted multiple software setups and test files.
• ✅ Corresponded with vendor for support since March.

💬 Vendor Response Summary

After months of emails, the only concrete suggestion provided was:

• “Timing pulley not tightened”

Vendor has not offered a replacement unit, detailed repair steps, or remote debugging support.
Refund/return period has since expired.

🧠 Hypotheses & Possible Problems

🧪 Next Steps (Suggested for Diagnostic)

• Confirm pulley tension — check all timing pulleys and belts for tightness.
• Test motor drivers individually using manual step commands or another known-good controller.
• Use multimeter to verify voltage to stepper drivers and continuity of wiring.
• Try an alternate firmware (like GRBL or Marlin, if compatible) to isolate software issues.
• Test axes one at a time using G-code or control software to determine individual responsiveness.

📁 Supporting Materials

• 📸 Photos of machine & internal wiring
• 📹 Videos of test attempts (linked above)
• 📖 Original manual (if available)
• 🔌 Wiring diagrams (if available from vendor)

🧩 Goal

To assist in getting the machine operational, or identifying whether hardware replacement or modification is necessary.

If successful, the machine should be capable of:

• Interpreting G-code or SVG input
• Moving a pen across X-Y axes
• Lifting/lowering the pen on the Z-axis
• Outputting handwritten text or designs