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Hardware Specs

PCB rev 1.x

Specs reflect the current production revision (PCB rev 1.2). Minor physical changes may occur within the 1.x series; any compatibility-breaking changes will increment the major revision.

Quick specs

ESP32 dual-core MCU · 0.96" OLED · 6 buttons + slider · 4 RGBW LEDs · speaker + mic · microSD · USB-C · machined aluminum · 2.2 x 1.6 x 0.8 in · ~68 g

Full specifications

Category Detail
Microcontroller ESP32-PICO-MINI-02 dual-core MCU, Wi-Fi 2.4 GHz 802.11 b/g/n, Bluetooth Classic + BLE
Display 0.96" 128x64 monochrome OLED (SSD1306 family)
Audio MAX98357A digital I2S amplifier with on-board speaker; ICS-43434 MEMS microphone
Motion LIS2DH12 3-axis accelerometer
Lighting 4x SK6812 RGBW LEDs (3 front, 1 back) + 1 red indicator LED
Power 400 mAh LiPo battery, MAX17048 fuel gauge, MCP73831 charge controller, swappable battery pack. Hours of active time, weeks of standby/deep sleep
Storage microSD card slot (FAT32) for app storage and file browsing
Connectivity USB-C port with CP2102N USB-to-UART bridge (serial + charging)
Inputs 6x tactile buttons + 1 analog slide potentiometer, hardware RC debounce + firmware debouncer
Voltage regulation 3x AP2112K-3.3 LDO regulators (main logic, OLED, LEDs/peripherals) for fine-grained power control
Dimensions 2.2 x 1.6 x 0.8 in (55.3 x 41.3 x 19.6 mm)
Weight ~68 g (varies by backplate design)
Enclosure Precision-machined aluminum chassis with replaceable backplate. 3D-printable models available
Assembly Ships as a kit — no soldering, just screws. Designed for repairability and customization
Development Arduino (ESP32); best experience with VS Code + PlatformIO (via pioarduino). CircuitPython hardware support designed-in but currently untested

Block diagram

graph TD
    MCU[ESP32-PICO-MINI-02] -->|I2C| OLED[SSD1306 OLED]
    MCU -->|I2C| ACCEL[LIS2DH12 Accelerometer]
    MCU -->|I2C| FUEL[MAX17048 Fuel Gauge]
    MCU -->|I2S TX| AMP[MAX98357A Amplifier + Speaker]
    MCU -->|I2S RX| MIC[ICS-43434 MEMS Mic]
    MCU -->|GPIO 0| LEDS[4x SK6812 RGBW LEDs]
    MCU -->|SPI| SD[microSD Card]
    MCU -->|GPIO| BTN[6x Buttons]
    MCU -->|ADC| SLIDER[Slide Potentiometer]
    MCU -->|UART| USB[CP2102N USB-C Bridge]
    BATT[400 mAh LiPo] --> CHRG[MCP73831 Charger]
    CHRG --> MCU
    USB -->|Charge| CHRG

Power architecture

Three independent AP2112K-3.3 regulators allow the firmware to selectively power down subsystems for low-power modes:

Regulator Rail Supplies
Main 3.3V ESP32 MCU
OLED 3.3V_OLED SSD1306 display (GPIO 12 enable)
AUX 3.3V_RGB SK6812 LEDs, audio amp, mic, slider, SD card, provisional hall sensors (GPIO 2 enable)

See also