Merit-IoT

A Tech Review of their Affordable Stepping Stone

The STM32-NUCLEO development board is a practical, affordable option for embedded computing — and it's surprisingly well-suited for agriculture and Internet of Things.

Here’s a short guide for growers, students, or anyone curious about why Merit-IoT uses STM boards in our field tests.

Unboxing the F446RE

The STM32-NUCLEO is a family of development boards created by STMicroelectronics. Each board features:

• An STM32 microcontroller (based on ARM Cortex)
• Built-in ST-LINK debugger (no separate programmer required)
• Arduino-compatible headers for shields
• Breadboard-friendly layout for quick prototyping

You can power it over USB, connect sensors directly, or build into a larger project using LoRa or Wi-Fi.

Why Use It on the Farm?

The STM32-NUCLEO is perfect for:

• Collecting soil moisture and temperature data using analog sensors
• Logging sensor readings to an SD card or serial terminal
• Pushing real-time values to a ThingsBoard dashboard over LoRa or Wi-Fi
• Controlling relays or pumps in response to thresholds

We’ve used it in greenhouse and raised bed tests to read soil data, measure air temp, and even control timed irrigation.

Programming Options

• Supports Arduino IDE (easier, quick-start)
• Fully compatible with PlatformIO and STM32CubeIDE (for advanced workflows)
• USB plug-and-play for flashing and serial monitoring

Code libraries for sensors like DHT11, DS18B20, and analog soil probes are widely available.

Pros

• Inexpensive and easy to source
• Open-source and widely documented
• Modular and expandable (can grow with your project)
• Great for classroom or community education

Considerations

• Requires some programming familiarity (C/C++ or Arduino)
• Needs a 3.3V-safe sensor setup (some 5V sensors work, others don’t)
• More hands-on than a commercial plug-and-play system

Bottom Line

If you want to build your own smart sensor, the STM32-NUCLEO is a solid foundation — especially when paired with ThingsBoard, LoRa modules, or SD logging.

We use it at Merit-IoT because it’s:

• Affordable
• Easy to teach
• Flexible enough to prototype real-world farm tools