This project redesigned the core electronics of a mature connected toy without changing its appearance or user-facing behavior. I was primarily responsible for firmware porting and validation after the MCU change, assisted with board testing and debugging, and designed the production-test fixture circuitry and firmware.
MCU migration and product-cost redesign
The previous architecture used an STM32F0 MCU and a separate Bluetooth device. We moved to an ESP32-C3, ported the existing firmware, and validated Bluetooth communication with Android and iOS applications together with ultrasonic sensing, motor control, and other peripheral behavior across supported hardware configurations.
The redesign preserved product functionality and production stability while reducing standby power enough to extend battery life by more than 20%, and reducing unit cost by more than 30%.
During porting, I found a memory-integrity issue in the ESP32 Arduino framework under extreme conditions, implemented a fix, and reported it to the developer community.
Browser-based configuration
Inspired by Betaflight Configurator, I designed a browser-based tool for firmware configuration, tuning, and OTA updates. The configurable architecture allowed several PCB variants to be consolidated into one hardware design, reducing firmware complexity and maintenance work while simplifying production validation.
Automated production testing
I designed the fixture circuit, excluding PCB layout, and developed its firmware around Raspberry Pi CM4 and RP2040. The fixture standardized programming and functional testing with:
- Automatic hardware detection and firmware programming.
- Controlled device power and fixture detection to reduce short-circuit and handling risk.
- Automated Bluetooth, ultrasonic-sensor, motor, and peripheral tests.
- Parallel fixture operation without Bluetooth or workflow interference.
- Live progress and results, cloud-backed production records, and remote debugging for engineering support.
The result replaced a manual, error-prone process with a repeatable production workflow that improved throughput and traceability.