Project: Lit
Role: Founder and Developer
Overview #
Black Beauty is the third chapter in developing Lit, representing a refined wearable prototype that balances aesthetics, functionality, and weight. Paired with the custom-built 3000mAh Power Pack, this iteration tackled challenges in power management, construction techniques, and overall usability. While the hardware is sound, firmware issues and power system limitations provide key areas for future improvements.
Objectives and Challenges #
- Weight Reduction: Optimize the hat’s weight for long-term comfort, addressing the shortcomings of previous prototypes.
- Refined Construction Techniques: Implement more precise and efficient methods for mounting and wiring components, ensuring durability and reliability.
- Power System Optimization: Integrate a compact and lightweight power pack with USB pass-through capabilities.
- Field Testing: Test the prototype in real-world conditions, exposing limitations in both hardware and software.
My Contributions #
1. Construction and Assembly #
- Holes and Mounting: Enlarged and customized the hat’s pre-punched holes using leather punches, achieving a precise fit for the heart-shaped LED PCBs.
- Wiring: Transitioned to 22-gauge solid-core wire, simplifying the soldering process and improving overall assembly time and durability. Used stranded-core wire for terminal connections, where flexibility was critical.
- Lens and Waterproofing: Mounted 140° lenses on the top-facing LEDs, secured with carefully mixed epoxy, which also provided light diffusion and waterproofing.
- PCB Securing: Used masking tape to hold PCBs during assembly, ensuring correct orientation and alignment.
2. 3000mAh Power Pack Development #
- Designed and built a custom power pack featuring:
- TP4056 USB-C Charging Module for safe and efficient charging.
- USB Pass-Through Circuit using P-Channel Mosfets and a Zener diode, allowing the device to run on USB power while preserving battery health.
- Voltage divider circuit for battery monitoring, enabling the microcontroller to measure battery levels safely.
- Wrapped the power pack in electrical tape for field deployment, ensuring a lightweight, compact design while protecting internal components.
3. Weight Optimization #
- Minimized wiring length and optimized gauge to balance durability and weight reduction.
- Eliminated unnecessary components and improved epoxy application to avoid excess weight from reapplications.
4. Field Testing and Lessons Learned #
- Field Testing: The hat was tested during travel and live events, demonstrating comfort and wearability despite sporadic firmware issues.
- Firmware Challenges:
- Experimental firmware and usermods caused instability and frequent re-flashing.
- Corruption of configuration files occurred due to the limitations of the LDO voltage regulator on the microcontroller.
- Power System Limitations:
- Phantom power draw: Identified potential leakage from pull-up/down resistors and the voltage divider circuit.
- Lack of voltage regulation led to instabilities when the battery voltage dropped below nominal levels.
5. Future Improvements #
- Introduce a regulated 5V switched-mode converter for stable voltage output and better microcontroller performance.
- Move current-sensing circuits to a dedicated board and gate voltage monitoring behind the power switch.
- Replace the SPDT switch with a soft power switch for improved durability and clean shutdowns, reducing risk of data corruption.
Outcomes #
- Functional Prototype: Achieved a wearable, lightweight hat with refined construction techniques and integrated LED panels.
- Enhanced Comfort: Weight optimizations allowed for extended wear during travel and events.
- Identified Areas for Improvement: Highlighted key limitations in firmware reliability, power system design, and control mechanisms.
Technical Summary #
- Skills: Electrical Engineering, Power System Design, PCB Design, Wearable Technology Development
- Tools: ESP32-S3, TP4056, IRF4905 P-Channel Mosfets, JST-XH Connectors, Leather Punches, Epoxy
- Features: USB Pass-Through, Battery Voltage Monitoring, LED Waterproofing, Lightweight Construction
Gallery #
Construction #
3000mAh Power Pack #
Product #
