SparkFun IoT RedBoard - Arduino UNO R4 form factor WiFi and Bluetooth boards with Raspberry Pi RP2350 or ESP32

 SparkFun IoT RedBoard: Arduino UNO R4 form factor WiFi and Bluetooth boards with Raspberry Pi RP2350 or ESP32

The Arduino UNO R4 form factor-based "IoT RedBoard – RP2350" and "IoT RedBoard – ESP32" boards from SparkFun were recently released. They are based on the Raspberry Pi RP2350B + RM2 wireless module and the ESP32-WROOM-32E WiFi and Bluetooth module, respectively.

A microSD card for storage, battery support, USB and DC jack power input, Arduino UNO headers, a Qwiic connection for expansion, a few buttons, and LEDs are all included on both boards. Additionally, the RP2350 board includes a HSTX connector, which is mostly used to operate SPI or HDMI displays.

The series includes two versions:

• IoT RedBoard – RP2350: Powered by the Raspberry Pi RP2350B MCU with an integrated RM2 wireless module, offering Wi-Fi 4 and Bluetooth 5.2.

• IoT RedBoard – ESP32: Built around the ESP32-WROOM-32E module, supporting Wi-Fi and Bluetooth 4.2 for robust IoT applications.

Both boards come with standard Arduino UNO headers, a Qwiic connector for easy expansion, a microSD card slot for additional storage, and multiple power input options, including USB-C, DC jack, and battery support.

Technical Specifications

Processing & Memory

RP2350 Model

• Microcontroller: Raspberry Pi RP2350B
• CPU:
• Dual-core Arm Cortex-M33 @ 150 MHz with TrustZone & Secure Boot
• Dual-core RISC-V Hazard3 @ 150 MHz
• Up to two cores can run simultaneously
• Memory:
• 520 KB on-chip SRAM
• 8MB external PSRAM
• 16MB onboard Flash storage

ESP32 Model

• Microcontroller: ESP32-WROOM-32E
• CPU:
• Dual-core Tensilica LX6 @ up to 240 MHz
• Memory:
• 520 KB SRAM
• Flash Storage Options: 4MB / 8MB / 16MB

Wireless Connectivity

RP2350 Model

• Wireless Module: Raspberry Pi RM2
• Connectivity:
• Wi-Fi 4 (2.4 GHz)
• Bluetooth 5.2
• Antenna: PCB Antenna

ESP32 Model

• Wireless Connectivity:
• Wi-Fi 2.4 GHz
• Bluetooth 4.2 BR/LE
• Antenna: PCB Antenna

Storage & Expansion

• MicroSD Card Slot (both models)
• Arduino UNO R4 Headers for expansion
• Qwiic Connector for easy sensor and module integration
• HSTX Display Connector (RP2350 model only) – Supports SPI/HDMI display interfacing

Power & Management

• USB Type-C Port for power and programming
• DC Jack Input (6V-15V) for flexible power supply options
• Battery Support: 2-pin connector for LiPo battery
• Charging Circuit: MCP73831 Single-Cell LiPo Charger
• Battery Monitoring: MAX17048 Fuel Gauge

Buttons & Indicators

RP2350 Model

• Buttons: Reset, Boot, User
• LEDs: Power, Charging, 2x User LEDs

ESP32 Model

• Buttons: Reset, Boot
• LEDs: Power, Charging, Tx/Rx, User LED
• Additional RGB LED: WS2812 RGB LED

Development & Software Support

Both IoT RedBoard models are open-source hardware, but each follows a different PCB design approach:

• RP2350 model: Designed using KiCad
• ESP32 model: Developed using Eagle CAD

Software & Firmware

• RP2350 Model:
• Supports MicroPython & Arduino development
• Documentation available on Sparkfun Docs
• Code samples available on GitHub
• ESP32 Model:
• Preloaded with MicroPython
• Supports Arduino IDE & ESP-IDF
• Documentation on Sparkfun Learn

While ESP32-based boards with Arduino UNO R4 form factors are common, such as the Adafruit Metro ESP32-S3 and Banana Pi BPI-ESP32, RP2350-based boards following this layout are relatively rare. The IoT RedBoard – RP2350 is among the first to offer Wi-Fi & Bluetooth functionality, making it a strong alternative to the Arduino UNO R4 WiFi.

Pricing & Availability

• IoT RedBoard – ESP32: $29.95 (Single-chip ESP32 module)
• IoT RedBoard – RP2350: $39.95 (RP2350 + RM2 module)

Both boards are now available for purchase, offering developers and hobbyists a powerful and flexible platform for IoT, embedded systems, and prototyping projects.