The Epi C3: A Compact ESP32-C3 Development Board with USB-C and Ceramic Antenna

The Epi C3 is a miniature development board featuring the Espressif ESP32-C3 microcontroller, equipped with a USB-C connector for power and programming, and an onboard ceramic antenna optimized for wireless communication.

This board joins the ranks of other compact ESP32-C3 boards like the Microflex series, ESP32-C3-0.42LCD, XIAO ESP32C3, and LOLIN’s C3 Mini and C3 Pico. However, the Epi C3 distinguishes itself as the “smallest ESP32 dev board” with both a USB-C port and a ceramic antenna. It uses a Johanson ceramic antenna praised for its impressive range, while the recessed USB-C connector further minimizes its footprint.

Compared to its predecessor, the Epi 32U4, the Epi C3 features a significantly more powerful 32-bit RISC-V ESP32-C3 microcontroller, replacing the older 8-bit AVR chip. It retains protective features from the Epi 32U4, such as TVS diodes on USB lines, a 500mA polyfuse on the USB power line, and ferrite beads for noise filtering. Additionally, it integrates a linear voltage regulator capable of delivering up to 3.3V at 500mA.

Epi C3 specifications:

• MCU– Espressif Systems ESP32-C3FH4, single-core 32-bit RISC-V microcontroller @ up to 160 MHz; 400 KB SRAM; 4MB flash
• Networking – 2.4 GHz WiFi 4 and Bluetooth 5.0 LE
• USB
  • USB-C connector for power and programming
  • ESD and surge protection on USB data lines and power input
• Expansion – 17x castellated headers (1.27mm spacing), with 12x available GPIOs, analog pins, reset, boot, power pins, and GND
• Misc – Reset and boot mode switches
• Power Supply
  • Input voltage – 3.62V to 5.5V via VIN; ~5V via USB-C
  • Linear voltage regulator – 600mA @ 3.3V
  • 500mA polyfuse
  • Ferrite beads for noise suppression,
• Dimensions – 23  x 12.75 x 3.9 mm

The board comes preloaded with Arduino firmware configured for the ESP32-C3 dev module, making it beginner-friendly. While the GitHub repository includes specifications for a variant with a U.FL antenna, this version is not currently available for purchase.

The Epi C3 is priced at $20 on Tindie, available in limited quantities. Users can opt to purchase the board with or without male headers.

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