ATMegaZero - ATmega32U4 + ESP32-S2 = EspinalLab's Latest and Greatest Raspberry Pi Zero Compatible

New 32-bit processor and 3v3 logic brings greater Pi HAT compatibility, plus CircuitPython!

A mere eight months ago, we shared a preview of a curious Raspberry Pi Zero doppelganger, the ATMegaZero from Eddie Espinal. The board's creation was then funded on Hackster Launch, and we even went hands-on with it once it reached production. The ATMegaZero ecosystem has continued to grow since then — mostly in the form of ATMegaZero shields (also compatible with the Raspberry Pi!) — until now, with the launch of the new ATMegaZero ESP32-S2 board, again on Hackster Launch (powered by GroupGets)!

The first thing that we noticed as prototypes began to emerge on Twitter was the fun shapes on the GPIO pins — or — wait a minute — those aren't just for fun: the orthogonal squares correspond to GND, while the rotated squares represent 3v3! Neat! The board retains many of the design decisions of its predecessor, such as the integrated microSD card, as well as the OLED display port (on a traditional Pi, typically this would be a camera connector), but also features a number of enhancements. The headline is of course the 32-bit Espressif ESP32-S2, which dwarfs the performance of the 8-bit ATmega32U4 from which the original took its name. The ESP's built-in Wi-Fi obviates the need for the optional ESP-01S ESP8266 module required by the original board to get online, simplifying the design and dramatically improving throughput.

A single RGB Neopixel replaces the individual LEDs of the original, and a whopping 32MB of SPI Flash and 8MB of PSRAM eliminate any of the conding restrictions of its predecessor. Final tweaks include the addition of a BOOT button in addition to RST, as shown in the above render. A 3d antenna, pictured below, further optimizes Wi-Fi performance.

One of the most exciting features of the new board is actually less about flashy new hardware, and more to do with the software you can flash. Out of the box, the ATMegaZero ESP32-S2 is compatible with CircuitPython, the Arduino alternative that is both easy to get started with, and incredibly powerful to iterate on, compared to the traditional compile/upload/wait/repeat loop. Arduino fans can of course still use the Arduino IDE and extensive range of libraries, and even Raspberry Pi fans are catered to by the new board's shift to 3.3 volt logic, meaning far greater compatibility with existing HATs, and especially the more diminutive pHATs.

A look at its key features:

  • 32-bit 240 MHz single-core Espressif ESP32-S2 processor
  • 32MB SPI Flash (actual usage currently limited to 16MB due to firmware limitations)
  • 2.4 GHz 802.11b/g/n Wi-Fi
  • 3D Antenna
  • microSD card holder
  • RGB Neopixel
  • FPC OLED display Connector
  • Micro USB power
  • Raspberry Pi Zero form factor
  • Colorful 2x20 GPIO header pins (soldering required)

The ATMegaZero ESP32-S2 is now available for pre-order via the Hackster Launch campaign on GroupGets. The original ATMegaZero, as well as a plethora of Raspberry Pi-compatible shields and accessories, are in stock and ready to ship from the ATMegaZero shop!

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