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Dec 23, 2023

Adafruit's Metro ESP32

Adafruit has unveiled another new entry in its Metro family of Arduino UNO form factor development boards, and this time it's the Espressif ESP32-S3's time to shine: meet the Metro ESP32-S3. "What's

Adafruit has unveiled another new entry in its Metro family of Arduino UNO form factor development boards, and this time it's the Espressif ESP32-S3's time to shine: meet the Metro ESP32-S3.

"What's Metro-shaped and has an ESP32-S3 WiFi module? What has a STEMMA QT connector for I2C devices and a Li-poly charger circuit? What has your favorite Espressif WiFi microcontroller and lots of memory for your next IoT project," Adafruit rhetorically asks by way of introduction for its new board. "That's right — it's the new Adafruit Metro ESP32-S3!"

The Espressif ESP32-S3 module at the heart of the board packs two 32-bit Tensilica Xtensa LX6 cores running at up to 240MHz, a Wi-Fi radio, and Bluetooth Low Energy (BLE) capabilities, along with 512kB of static RAM (SRAM), 8MB of pseudo-static RAM (PSRAM) and 16MB of flash storage for programs. To this, Adafruit has added a Metro carrier — meaning a footprint and pin-out which mimics the popular Arduino UNO.

Elsewhere on the board is a USB Type-C connector for data and power, a battery connector with charging circuit for optional lithium-polymer batteries, a microSD slot for storage, physical reset and boot-mode buttons, a JTAG header, optional serial debug pins, and a STEMMA QT connector for expansion with I2C devices.

The Metro ESP32-S3 comes less than a month after Adafruit unveiled the Metro RP2040, which — as its name suggests — uses a dual-core Raspberry Pi RP2040 microcontroller as its heart. This, in turn, followed on from the Metro M7, based on NXP's i.MX RT1011 "crossover microcontroller unit" — offering a much more powerful take on the Arduino UNO form factor, which itself has since been updated with the release of the modernized UNO R4 Minima and WiFi.

According to Adafruit's internal testing, the board is well-suited to low-power projects. "In deep sleep mode we can get down to ~100µA of current draw from the Li-poly connection," the company claims. "Quiescent current is from the power regulator, ESP32-S3 chip, and Li-poly monitor. Turn off the NeoPixel and external I2C power for the lowest quiescent current draw."

The board is listed on the Adafruit store at $24.95 before volume discounts, but at the time of writing had not yet gone up for sale.