UNO R3 form-factor board built around a 48MHz Renesas RA4M1 with onboard ESP32-S3 Wi-Fi/BLE, USB-C power, Qwiic connector, and a 12x8 LED matrix—ideal for connected prototypes without stacking extra shields.

I leaned hard on the UNO R4 WiFi for a pair of fall workshops, and it still earns its spot as my default connected Uno. The 48MHz Renesas RA4M1 handles sensor sampling while the onboard ESP32-S3 streams data to an MQTT broker over WPA3 without stuttering, and USB-C finally means I can power a breadboard from the same cable as my laptop. The Qwiic connector saved me time in class—students snapped on IMUs and environmental sensors without soldering or jumper spaghetti—and the 12x8 LED matrix made it trivial to show status icons and error states. Libraries that expect AVR registers still need minor tweaks, but the official ArduinoCore-renesas package covers most of the common APIs now. Idle draw is around 90 mA with Wi-Fi on, so it’s not a coin-cell board, yet for mains-powered IoT builds or rapid prototyping the R4 WiFi remains the sweet spot in 2025.

UNO R4 WiFi combines 48MHz Renesas RA4M1 with ESP32-S3 for connected projects. Includes USB-C, Qwiic connector, and 12x8 LED matrix without extra shields.

Arduino UNO R4 WiFi Development Board with ESP32-S3

Arduino UNO R4 WiFi

Compact RP2040‑based microcontroller board with 2.4 GHz Wi‑Fi for affordable embedded and IoT projects.

The Pico W is still my favorite quick-deploy microcontroller. For $10-ish you get the dual-core RP2040, built-in 2.4 GHz Wi-Fi, and enough RAM to run MicroPython web servers or C++ FreeRTOS projects. I’ve used it for Home Assistant sensors, MQTT air-quality probes, and even a tiny serial console for my Pi cluster. CircuitPython support has matured nicely and the UF2 bootloader makes firmware updates as simple as dragging a file. The official SDK exposes Wi-Fi primitives for C/C++ and there’s now native support in MicroPython 1.22, so you can stand up sockets with a few lines. My only nit: there’s still no BLE radio, so if you need Bluetooth you’ll need an external module or the Pico 2. For Wi-Fi-enabled tinkering and teaching embedded basics, nothing competes at this price.

Compact RP2040 microcontroller with built-in 2.4GHz Wi-Fi. Perfect for IoT projects and embedded development with MicroPython, CircuitPython, or C SDK.

Raspberry Pi Pico W with Built-In Wi-Fi and RP2040

Raspberry Pi Pico W

Curated iot products we use and recommend. Each item tested in real-world scenarios. Find 2 products with detailed reviews, pros, and cons.

IoT Products

Arduino UNO R4 WiFi

Raspberry Pi Pico W