Bee Motion S3

ESP32-S3 board with an onboard PIR motion sensor - perfect for automation and presence-based triggers.

USB-C Native USB
Bee Motion S3 board
ESP32-S3
MCU
240MHz
clock
8MB
flash
512KB
SRAM
25· 11 ADC
GPIO
BLE 5.0+ WiFi
radio
On this page

Pinout

25 pins
View:
PinGPIOLabelsStatusCapabilitiesNotes
10BOOT_BTNstrapping-
21VBAT_VOLTAGEPWMsafe-
32VBUS_SENSEPWMsafe-
43LIGHTPWMstrapping-
54PIRPWMsafe-
65SSA5D5T5PWMsafeadc · touch · spi
76A6D6T6PWMsafeadc · touch
87A7D7T7PWMsafeadc · touch
98A8D8T8PWMsafeadc · touch
109A9D9T9PWMstrappingadc · touch
1110A10D10T10PWMstrappingadc · touch
1211A11D11T11PWMstrappingadc · touch
1312A12D12T12PWMstrappingadc · touch
1413A13T13PWMstrappingadc · touch
1514A14D14T14PWMstrappingadc · touch
1615MOSIA15D15PWMsafeadc · spi
1716MISOD16PWMsafespi
1817SCKD17PWMsafespi
1934LDO2RGB_PWRPWMstrapping-
2035SDOD35PWMstrapping-
2136SCLD36PWMstrappingi2c
2237SDASDID37PWMstrappingi2c
2340RGB_DATAPWMstrapping-
2443TXD43PWMstrappinguart
2544RXD44PWMstrappinguart

Start with these

10 pins with no boot or system involvement
VBAT_VOLTAGEPWMVBUS_SENSEPWMPIRPWMSSA5A6D6A7D7A8D8MOSIA15MISOD16SCKD17

Freely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.

Fine - with a little care

sampled at boot or shared with debug/serial
PinLabelWhat to knowRole
BOOT_BTNGPIO0Must be pulled high (default) or low (to enter UART download mode) at reset. Using it for other functions can interfere with boot mode configuration.Strapping
LIGHTGPIO3Sampled at reset to select JTAG interface (USB Serial/JTAG controller vs. external pins). Improper use can disable external JTAG or alter debug interface.Strapping
RGB_DATAMTDO (GPIO40)Default JTAG TDO output for debugging. Using it as GPIO will interfere with JTAG debugging functionality.Other
TXU0TXD (GPIO43)Used for bootloader output and UART console logs. If repurposed, you will lose the default serial output (and programming via UART0).Other
RXU0RXD (GPIO44)Used for bootloader input (download mode via serial). If repurposed, you cannot use the default UART0 download mode for programming the chip.Other

Only if you know the tricks

wired to flash or USB - expect a fight
PinLabelWhat to knowRole
A9FSPIHDConnected to external flash (data/hold signal) on most modules. Not recommended for use as GPIO, since it must remain dedicated to flash communication.Flash
A10FSPICS0Used to select the external flash chip. It is required for flash access and cannot be repurposed without losing flash connectivityFlash
A11FSPIDUsed as a data line for flash (and in-package PSRAM). It should not be used as GPIO when the flash/PSRAM is in use.Flash
A12FSPICLKDrives the flash (and PSRAM) clock. This critical signal must be reserved for memory and not used as general GPIO.Flash
A13FSPIQUsed as a data line for flash/PSRAM transfers. Not available for other uses when flash/PSRAM is connected.Flash
A14FSPIWPConnected to external flash (data/write-protect signal). Not recommended as GPIO because it’s reserved for flash operations.Flash
LDO2FSPICS0Wired to the chip select of the internal flash in flash-equipped variants. It must remain low during flash operation, so it’s not available for other use.Flash
SDOFSPID / PSRAM_D0In modules with octal PSRAM, this pin is connected to the PSRAM data line. It is reserved for memory interface and not free for general GPIO when flash/PSRAM is present.Flash
SCLFSPICLK / PSRAM_CLKIn modules with octal PSRAM, this pin drives the PSRAM clock. It must be dedicated to the memory interface, not used as a regular GPIO when that interface is in use.Flash
SDAFSPIQ / PSRAM_DQSIn modules with octal PSRAM, this pin is connected to the PSRAM’s DQS signal. It cannot be repurposed without disrupting the PSRAM/flash communication.Flash
These are recommendations, not hard rules - with the right pull-ups, timing and boot-state awareness most pins can be made to work. When in doubt, start green.
Pinout notes The Bee Motion S3 pinout brings out 25 GPIO pins - every one of them usable in your project. For peripherals, I²C is mapped to SDA on GPIO37 and SCL on GPIO36;…

The Bee Motion S3 pinout brings out 25 GPIO pins - every one of them usable in your project.

For peripherals, I²C is mapped to SDA on GPIO37 and SCL on GPIO36; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO43 and GPIO44 cover serial logging and flashing.

On the analog side there are 11 ADC-capable pins for sensors and battery monitoring and 10 capacitive-touch inputs.

If you want zero surprises, VBAT_VOLTAGE, VBUS_SENSE, PIR, SS and 6 more are free of any such role - the safest first picks. 5 of the exposed pins carry boot-time or system duties on the ESP32-S3 (BOOT_BTN, LIGHT, RGB_DATA and 2 more).

Getting started

flash your first firmware in ~2 minutes
Tool:
1
Connect over USB
Native USB - shows up as a port right away, no driver needed. Not detected? Hold BOOT while plugging in.
2
Match & flash
Set the Tools options shown, then click Upload.
3
Verify it runs
The onboard LED on GPIO1 blinks - swap the pin if your board's LED differs.
Set these in Tools · leave everything else at default
Arduino IDE 2.x — Tools Copy
Board: "ESP32S3 Dev Module"
USB CDC On Boot: "Enabled"
Flash Size: "8MB (64Mb)"
Flash Mode: "DIO"
Partition Scheme: "8M with spiffs (3MB APP / 1.5MB SPIFFS)" (default)
Upload Speed: "921600"
▸ every other Tools option — leave at default
Board: ESP32S3 Dev Module
USB CDC On Boot: Enabled
Flash Size: 8MB (64Mb)
Flash Mode: DIO
Partition Scheme: 8M with spiffs (3MB APP / 1.5MB SPIFFS)
Upload Speed: 921600
Find it: Tools ▸ Board ▸ ESP32 Arduino ▸ ESP32S3 Dev Module
blink.ino Copy
// blink the onboard LED
void setup() {
  pinMode(1, OUTPUT);
}
void loop() {
  digitalWrite(1, HIGH); delay(500);
  digitalWrite(1, LOW);  delay(500);
}
board to selectesp32-s3-devkitc-1⧉ copy
platformio.ini Copy
[env:Bee_Motion_S3]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600
Find it: PlatformIO Home ▸ Boards, search esp32-s3-devkitc-1 — or type it after board =.
board to selectesp32-s3-devkitc-1⧉ copy
device.yaml Copy
esp32:
  board: esp32-s3-devkitc-1
  variant: Bee_Motion_S3
  framework:
    type: esp-idf

# blink - GPIO1
output:
  - platform: gpio
    pin: 1
    id: led_out
light:
  - platform: binary
    name: "LED"
    output: led_out
Find it: search ESPHome's board list for esp32-s3-devkitc-1 (same ids as PlatformIO).
esptool doesn't pick board settings — a prebuilt .bin already has them baked in. This is just the raw flash command.
terminal Copy
esptool.py --chip esp32s3 --port /dev/ttyACM0 \
  --baud 921600 write_flash 0x0 firmware.bin
--port = your /dev/tty* (macOS/Linux) or COMx (Windows).
Build details: sketch space 1310720 B · data 327680 B · DIO

Specifications

ESP32-S3
Compute
MCU
ESP32-S3
Clock
240 MHz
SRAM · Flash
512 KB · 8MB
Radio
Wi-Fi
802.11 b/g/n
Bluetooth
5.0 LE
Antenna
PCB
I/O
GPIO · ADC
25 · 11
UART · I²C · SPI
3 · 2 · 4
PWM
8 channels
Power
USB
USB-C
Serial
Native (CDC)
Boot address
0x0
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · QIO
Sketch · Data
1.25 MB · 320 KB
The Bee Motion S3 uses esptool_py for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is DIO with QIO boot mode. The maximum sketch size is 1.25 MB with 320 KB available for data.

About this board

At its core is the ESP32-S3 - a dual-core Xtensa with vector extensions suited to AI workloads.

Expect to pay about $29.99 - in line with other ESP32-S3 boards.

Onboard you'll find a STEMMA QT connector, an addressable RGB LED (GPIO40), a motion sensor (S16-L221D), an ambient-light sensor, battery charging (MCP73831) and Reset/Boot buttons.

It flashes over native USB - no serial-converter driver needed, which isn't a given among ESP32-S3 boards.

Where to buy

prices are typical street prices
Bee Motion S3
Bee Motion S3
$29.99per unit, typical

Resources

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