This is a portable LED controller based on the ESP32 SoC. It is powered by 18650 lithium-polymer batteries and it is designed to synchronize LED patterns with music. To achieve this, I developed an analog circuit with a high SPL microphone connected to a PCM1808 DAC via a low-pass filter preamplifier. The input signal to the ESP32 is in digital format using the I2S standard.
Developing First prototypes
Demoboard prototype
I developed a prototype using an ESP32 DevKit demo board, which was also connected to a I2S MEMS microphone, a rotary encoder and an OLED display.
This testing circuit allowed me to evaluate the ESP32’s performance, allowing me to explore potential future features such as integrating an LCD or an encoder into the LED controller.
The “motherboard” prototype
I created a custom circuit that allowed me to test both the Battery Management System (BMS) and the battery charging circuit. This circuit serves as the motherboard to connect the DC-DC converter powering the LEDs and the LED controller which are on different PCBs.
The cells are protected by a Battery Management System (BMS) designed to safeguard against overvoltage and overcurrent during both the battery charging and discharging phases.
The core of the battery charging circuit is the LTC4002, a DC-DC buck battery charger IC capable of charging the batteries at a current up to 1.5A.
Integrating the CPU and Logic circuitry
The next circuit I developed incorporates the CPU and integrated logic. It also features an I2C bus for connecting to an OLED, as tested with the devkit.
This controller can connect up to 2 independent strips of WS2813 pixel LEDs, powered by a synchronous buck DC-DC converter capable of delivering up to 15W of power with high efficiency.
The CPU and analog/digital circuits are powered at 3.3V by a low Iq DC-DC buck converter with power-good function.
Here is the functional prototype connected to a strip of pixel LEDs running a ‘scrolling color’ animation.
ing DIY 
