Unexpected Maker FeatherS3 Development Board (FeatherS3)
Unexpected Maker FeatherS3

Available from:


Install method:
USB to Serial

GPIO #Component
Configuration for ESP32-S3
Flash only with ESP32-S3 `tasmota32s3...` binaries. Download unofficial development build.

A Feather form factor ESP32-S3 dev board with 1S LiPo battery monitoring.

This board uses an ESP32-S3 chip with no onboard flash or PSRAM with an external 16 MB SPI flash chip and an external 8MB PSRAM chip.


When the board is booted into debug by holding BOOT and pressing the RESET button the USB-Serial chip on the USB port exposes a serial connection. This can be used to easily flash new firmware.

For flashing via tasmota32s3-bluetooth.factory.bin, download the tasmota32s3-bluetooth.factory.bin file.

esptool.py --chip esp32s3 --baud 115200 --before default_reset --after hard_reset --flash_mode dio --flash_size detect --flash_freq 80m write_flash --erase-all -z 0x0 tasmota32s3-bluetooth.factory.bin

Flash mode (dio) and frequency (80m) should be used when flashing, otherwise the new firmware won’t boot properly

Device Notes

Unexpected Maker FeatherS3 Front

Unexpected Maker FeatherS3 Pinout

FeatherS3 Schematic


  • WS2812B Neopixel
    • On GPIO40 (configured as WS2812) with power on GPIO39 (configured as Output Hi).
  • 1x Blue Status LED
    • On GPIO13 (configured as LED 1).
  • 1x Ambient light sensor (ALS-PT19)
    • On GPIO4 (configured as Analog2).
  • 2x STEMMA-QT JST-SH I2C bus connector
    • Both ports share the same bus, on GPIO9 (SCL) and GPIO8 (SDA) (configured as I2C 1). These ports are on the same bus as the SCL and SDA pins labelled on the board.
  • 1S LiPo battery management subsystem with 2-pin JST-PH connector
    • Battery voltage divider on GPIO2 (configured as Analog1) and 5V/USB voltage detection on GPIO34 (not configured)

GPIO Pin Mapping

The user pins labelled on the board are set up as User pins in the template.The pin numbers match the ESP’s internal GPIO number assignments allowing relatively easy module configuration without having to translate pin.

The only exception are the pins labeled TX and RX, which are set up as Serial TX/RX in the template.