Smart Bee Designs' Bee S3 Is a $10 Ultra-Low-Power Espressif ESP32-S3 Development Board

Using one of the last Espressif chips not to be built around the RISC-V ISA, this low-cost dev board draws under 20µA in sleep mode.

Smart Bee Designs has launched a compact development board built around Espressif's ESP32-S3, designed with ultra-low-power projects in mind: the Bee S3.

"I set out to make an ultra-low-powered ESP32 board and make it affordable," Smart Bee Design's Paul Price explains of the origin of his company's latest development board. "If you had this paired with a 1,500mAh LiPo battery, turning on once a day and sending a sensor reading over MQTT it would last for over five years!"

The breadboard-friendly Bee S3 is built around an Espressif ESP32-S3-MINI-1 module, the company's last to feature a dual-core Xtensa LX7 microcontroller prior to its decision to move to cores built exclusively around the free and open source RISC-V instruction set architecture. The chip includes vector instruction support for edge AI acceleration, 512kB of static RAM (SRAM), and a radio block supporting 2.4GHz 802.11b/g/n Wi-Fi and Bluetooth 5 Low Energy (BLE).

To this, Price has added a carrier board with 15 general-purpose input/output (GPIO) pins, of which eight can act as analog inputs, plus an on-board RGB LED. The Bee S3 also offers dedicated boot-mode and reset buttons, a USB Type-C connector for data and power, and a connector for an optional 1S lithium-polymer battery — making full use of a claimed ultra-low-power sleep mode down to less than 20µA.

The Bee S3 isn't Price's first entry in the Bee family: earlier this year Price launched the compact Bee Motion Mini and larger Bee Motion smart passive infrared (PIR) motion sensor boards, the former built using an Espressif ESP32-C3 RISC-V module and the latter the ESP32-S2. The Bee S3, though, marks the first model to use the ESP32-S3.

Like other models in the Bee family, the Bee S3 is open source with schematics and a 3D model published to GitHub under an unspecified license — along with sample code for the Arduino IDE, CircuitPython, and MicroPython.

The Bee S3 is now available on the Smart Bee Designs Tindie store for $10.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire:
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