Bee Motion
ESP32-S2 board with an onboard PIR motion sensor, USB-C and LiPo charging, built for battery-powered motion-detection projects.
Bee Motion Pinout
22 pins| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | BOOT_BTN | strapping | - | |
| 2 | 1 | A0T1PWM | safe | adc · touch | |
| 3 | 2 | A1PWM | safe | adc | |
| 4 | 3 | A2T3PWM | safe | adc · touch | |
| 5 | 5 | SSA4T5PIRPWM | safe | adc · touch · spi | |
| 6 | 6 | A5T6PWM | safe | adc · touch | |
| 7 | 7 | A6T7PWM | safe | adc · touch | |
| 8 | 8 | A7T8PWM | safe | adc · touch | |
| 9 | 9 | A8T9PWM | strapping | adc · touch | |
| 10 | 10 | A9T10PWM | strapping | adc · touch | |
| 11 | 11 | A10T11PWM | strapping | adc · touch | |
| 12 | 12 | A11T12PWM | strapping | adc · touch | |
| 13 | 13 | A12PWM | strapping | adc | |
| 14 | 14 | T14PWM | strapping | touch | |
| 15 | 15 | SCKPWM | strapping | spi | |
| 16 | 16 | MOSIPWM | strapping | spi | |
| 17 | 35 | SDOPWM | safe | - | |
| 18 | 36 | SDAPWM | safe | i2c | |
| 19 | 37 | SCLSDIPWM | safe | i2c | |
| 20 | 38 | MISOPWM | safe | spi | |
| 21 | 43 | TXPWM | uart | uart | |
| 22 | 44 | RXPWM | uart | uart |
Start with these
13 pins with no boot or system involvementFreely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
9 pins · 4 things to knowBOOT_BTNGPIO0 Bootstrapping pin; selects boot mode (SPI Boot vs UART Download). Strapping
Must be pulled high for normal boot; pulling low at reset enters bootloader (download mode). Also serves as SPI flash data-in (SPID) line when using external flash memory.
A8GPIO9A9GPIO10A10GPIO11A11GPIO12A12GPIO13T14GPIO14 General-purpose SPI2 (FSPI) IO MUX pins Other
IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet does not restrict it, so it is only taken if your board wires flash, an SD card or a display to FSPI.
- A8General-purpose SPI2 (FSPI) IO MUX pin - hold/data line (FSPIHD)
- A9General-purpose SPI2 (FSPI) IO MUX pin - chip select (FSPICS0)
- A10General-purpose SPI2 (FSPI) IO MUX pin - data in (FSPID)
- A11General-purpose SPI2 (FSPI) IO MUX pin - clock (FSPICLK)
- A12General-purpose SPI2 (FSPI) IO MUX pin - data out (FSPIQ)
- T14General-purpose SPI2 (FSPI) IO MUX pin - write-protect/data line (FSPIWP)
SCKGPIO15 32.768 kHz RTC crystal oscillator positive input (XTAL_32K_P); also functions as GPIO15 (U0RTS, ADC2_CH4). Other
If an external 32 kHz crystal is used for RTC, this pin is dedicated to the crystal and cannot be used as GPIO.
MOSIGPIO16 32.768 kHz RTC crystal negative input (XTAL_32K_N); also GPIO16 (U0CTS, ADC2_CH5). Other
If using an external 32 kHz crystal, this pin is connected to the crystal and should not be used as general I/O.
All 22 pins on the Bee Motion are usable GPIO.
Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO36 and SCL on GPIO37; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO43 and GPIO44 cover serial logging and flashing.
Beyond plain digital I/O you get 12 ADC-capable pins for sensors and battery monitoring and 11 capacitive-touch inputs.
9 of the exposed pins carry boot-time or system duties on the ESP32-S2 (BOOT_BTN, A8, A9 and 6 more) - check the guidance above before wiring anything to them. A0, A1, A2, SS and 9 more are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutesBoard: ESP32S2 Dev Module USB CDC On Boot: Enabled Flash Size: 4MB (32Mb) Flash Mode: DIO Partition Scheme: Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS) Upload Speed: 921600
// toggle GPIO1 - wire an LED and resistor to it
void setup() {
pinMode(1, OUTPUT);
}
void loop() {
digitalWrite(1, HIGH); delay(500);
digitalWrite(1, LOW); delay(500);
}[env:Bee_Motion]
platform = espressif32
board = esp32-s2-saola-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32-s2-saola-1 - or type it after board =.esp32:
board: esp32-s2-saola-1
variant: esp32s2
framework:
type: esp-idf
# blink - GPIO1
output:
- platform: gpio
pin: 1
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesp32-s2-saola-1 (same ids as PlatformIO).esptool.py --chip esp32s2 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x1000 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Specifications
ESP32-S2 · vs other ESP32 chips →About this board
Inside sits the ESP32-S2 - a single-core Xtensa with native USB-OTG and no Bluetooth.
The $19.99 price tag is typical for an ESP32-S2 board.
Around the module: a motion 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-S2 boards.
Where to buy
prices are typical street pricesResources
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