Current Status: Prototyping and soldering completed, entering the final testing and optimization phase
1. Current Progress ✅
Completed Work
| Project | Key Achievements | Time/Cost |
|---|---|---|
| PCB Prototyping | – JLCPCB 5 Yuan special board (5 pieces)– Manual soldering: only a few components (CH224K/USB-C interface), but USB-C is really difficult to solder manually | 1 week / ¥13.04 (including shipping) + 43.51 = 56.55 |
| Structural Components | – 3D printed shell (PLA + UV-curable resin)– Verification of screw/clip assembly | ¥23.6 (including shipping) |
| Soldering Assembly | – Completed soldering of 2 sets of samples– 100% visual inspection passed for key components like CH224K, USB-C, etc. | 3 hours (including rework) |
2. Testing Results 🔍
Core Function Testing
| Test Item | Method | Result | Issues |
|---|---|---|---|
| PD Protocol Trigger | U96P Tester + Apple 20W Charger | Successfully triggered at 9V/12V | Some third-party chargers are incompatible |
| LED Function | 5V power supply, mode switching test | RGB lighting effect normal | Uneven brightness (needs adjustment of current limiting resistor) |
| Structural Strength | 1-meter drop test (3 times) | No cracks, functions normally | Screw post slightly loose |
Extended Testing
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Temperature Rise Test: Full load for 30 minutes → Maximum shell temperature 48℃ (within safe range)
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Plug and Unplug Lifespan: USB-C interface plugged and unplugged 50 times → No contact failure
3. Issues Found and Solutions ⚠️
Hardware Issues
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Poor PD Protocol Compatibility
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In series with 100nF capacitor on CC line (filter interference)
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Version 2 uses IP2723T protocol chip (better compatibility)
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Reason: Some chargers have abnormal CC pin impedance
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Solution:
Uneven LED Brightness
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Reason: Current differences due to current limiting resistor tolerance
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Temporary Solution: Replace with 1% tolerance resistor
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Long-term Solution: Use constant current driver IC (e.g., AMC7135)
Structural Issues
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Loose Screw Post
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Fix: Apply a small amount of screw adhesive (Loctite 222)
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Optimization: Version 2 adds M2.5 screw holes (more vibration resistant)
USB-C Plug and Unplug Feels Stiff
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Adjustment: Use a round file to enlarge the opening by 0.2mm
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Optimization: Add guiding slope to the shell
4. Cost and Time Statistics 📊
| Project | Total Time | Total Cost |
|---|---|---|
| Design and Prototyping | 3 weeks | – |
| Material Procurement | – | Approximately ¥81 |
| Testing and Iteration | 1 week | – |
| Tools | 2 weeks | Approximately ¥300 |
| Total | 4 weeks | ¥381 |
5. Project Deliverables 📂
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Technical Documents:
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Final schematic (LCEDA)
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Structural model (Rhino 3DM + STL)
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BOM list (including alternative material information)
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Test Reports:
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PD protocol compatibility list
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Temperature rise/drop test videos
Summary and Recommendations
The project has successfully crossed the most challenging phase of hardware development from “0 to 1”!
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Core Achievements:
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Achieved PD fast charging + LED multifunctional integration
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Completed full process independent design (PCB + structure)
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Completed full product prototype verification
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Commercial Value:
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Can serve as the first hardware product (profit margin = 0%)
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Derivation potential: 0
A solid step has been taken from knowing to doing!