Background
After the success of my V0 LEDEarrings, which I have used on multiple occasions since the original concert, I wanted to make a new custom PCB version. I plan to make the earrings sync up together and be controllable over Bluetooth, so I designed them around the ESP32 C3 microcontroller.
Design
Power management is accomplished through a MAX16054 power management IC and a RT6150B 3.3v buck-boost regulator. When the push button on the earring is pressed, the power management IC enables the buck-boost converter which powers the MCU and LEDs. The MAX ic allows for additional presses of the push button to be read by the MCU to change mode settings without affecting the enable status of the regulator. The MCU can shut off the system by sending a signal to the clear pin of the power regulator IC.
As this is just my first prototype, I didn’t need the RF system to be perfect, and I wanted something that worked well enough for testing and development. I made a Pi matching network and fed that to a header where I could solder on a small wire as an antenna.
Instead of putting a charging IC and charger connection on the earrings itself, I put contacts on the PCB where a charging dock could connect using pogo pins.
Result
After receiving and assembling the PCB, I programmed the MCU over the UART connection and began testing. Unfortunately, there were several large issues which limited the success of this prototype. Issues with the power management circuitry caused the MCU to reset whenever I tried to upload code, requiring modifications to the circuitry. Additionally, the pads which I used to connect the programmer were SMD-only pads, which slowly started to peel up and break off the board, leaving me with no interface to program with MCU.
I finished this version by getting one earring to be able to light up and run. I plan to fix these issues and make improvements in a V2.
