Waveshare Launches the ESP32-S31-Zero

Development boards have a tendency to grow in size as manufacturers add more features, but Waveshare is packing a lot into a small footprint with its new ESP32-S31-Zero. Measuring just 28×18 mm, this tiny board is equipped with a powerful processor, multiple wireless connectivity options, and up to 32 MB of PSRAM — and it's still small enough to fit into almost any embedded project.

The board is built around Espressif's new ESP32-S31 microcontroller, which includes a dual-core 32-bit RISC-V processor running at up to 320 MHz. There's also a dedicated low-power RISC-V core for handling less demanding tasks without draining batteries. The chip includes 512 KB of SRAM, another 32 KB of low-power SRAM, and 320 KB of ROM.

Depending on the configuration, the board comes with either 16 MB or 32 MB of PSRAM, paired with 16 MB or 32 MB of SPI flash storage. That's a pretty generous amount of memory for such a small device, making it suitable for projects involving graphical interfaces, data processing, and other applications that need more resources than a typical microcontroller can provide.

Wireless connectivity is another strong point for this board. The ESP32-S31-Zero supports 2.4 GHz Wi-Fi 6, Bluetooth 5.4 Low Energy, Bluetooth Classic, and IEEE 802.15.4 for Zigbee and Thread networking. Both an onboard ceramic antenna and an IPEX-4 connector for attaching an external antenna are available. That makes it a good option for smart home devices, wireless sensors, and other IoT projects.

For expansion, there are 15 exposed GPIOs along its castellated edges, allowing it to be soldered directly onto a custom PCB. Waveshare also offers versions with pre-soldered headers for easier prototyping.

A 40-pin connector makes it easy to add extra hardware, such as LCD displays, touchscreens, and SD card readers, while also providing access to USB signals. There's even the possibility of adding Gigabit Ethernet through a custom expansion module, although that capability isn't directly supported by the board as shipped. Other features include a USB-C port for power, programming, and debugging, along with BOOT and RESET buttons and a programmable WS2812 RGB LED.

On the software side, Waveshare provides documentation, schematics, and examples covering everything from GPIO and UART to Wi-Fi and Bluetooth. Development is handled through Espressif's ESP-IDF framework, although the ESP32-S31 is currently considered a preview target, so software support is still maturing.

With its combination of processing power, memory, and wireless connectivity, the ESP32-S31-Zero has plenty to offer makers working on embedded projects. As the development tools mature, this tiny board could become a nice option for everything from smart home devices to custom wireless gadgets. The only configuration currently in stock is 16 MB of PSRAM with 32 MB of flash, and it is selling for $10.99.