Exciting developments are happening in the world of IoT hardware, particularly in Agile hardware development through a rapid prototyping process and early tech stack integration. Adopting Agile in IoT hardware development can streamline workflows, increasing flexibility compared to the traditional Waterfall method. Leveraging the Agile methodology for IoT hardware development, however, begins with using the right kind of board. Let’s explore our top picks for microcontrollers, microprocessors, and IoT boards necessary for building a robust IoT product.  

Dev Kits, Defined

You’ll hear us reference “dev kits” frequently throughout our top IoT board list. In short, a dev kit is a tiny, hackable computer that’s made for tinkering. More specifically, dev kits are usually single board computers (SBCs) with pre-certified RF communications and easy access to input/output (I/O) pins for interfacing with custom circuitry and firmware development for components.

Microcontroller (MCU) vs. Microprocessor (MPU)

Your choice of processor — MCU or MPU — will impact your bill-of-materials cost. A lower-powered MCU that runs either on embedded C or a real-time operating system (RTOS) will cost less than the more powerful MPU, which can run embedded Linux. 

However, while cost is one dimension of MCU vs MPU selection, a much more important one is capability. It comes down to software/firmware complexity. If all you need to do is read some sensors and transmit the data, an MCU is probably the best choice because it’s cheap and low power. If you need to do more complex operations such as machine learning or edge-hosted applications, then you’ll want a more powerful MPU — which will cost more and use more power.

MPU + Linux

Nerves, an IoT-specific platform developed in Elixir, is our preferred Linux solution for MPUs. It allows for a baseline target system’s rapid establishment, often within weeks, and has facilitated the development of a minimum viable product (MVP) within six months for our projects.

MCU + Embedded C/RTOS

For MCUs, Zephyr RTOS, an embedded C framework, offers built-in support for over 350 boards, easy scalability, and isn’t tied to any specific cloud offering. Additionally, recompiling the firmware for a different processor is surprisingly easy, making it perfect for lower-level, lower-cost microcontrollers.

Choosing an IoT Board

As you begin your search for an IoT board, there are several critical components to look out for.

The first is the board’s connectivity options. This goes without saying, given that a smart device is largely defined by its connectivity capabilities. You’ll also want to make sure the board supports peripherals and desired features. These can include common ports like USB or HDMI, buses for serial protocols like I2C and SPI, or pin-outs for pulse width modulation (PWM) devices like dimmable lights or servo motors. 

Lastly, open-source hardware (OSHW) is always a big plus. It’s a good sign if schematic and Gerber files — files that show the printed circuit board (PCB) designs —  are provided, too.

Top IoT Boards & Dev Kits in 2023

Without further ado, here are our top 10 IoT boards for product development and rapid prototyping in 2023. As of the writing of this blog, all of the boards listed come in under the $100 mark.

#1: i.MX6ULL Colibri SOM + Colibri Evaluation Kit

A new favorite target of ours is the NXP i.MX6ULL. It offers similar connectivity options as our previous favorite MPUs, but there seems to be more of the i.MX6ULL family in stock. Unfortunately, the same cannot be said for some of the dev kits we used before with this target.

After thorough searching, we discovered the Toradex Colibri i.MX 6ULL SOM, which pairs well with various host boards. We’ve been primarily using the full-featured Colibri Evaluation Board, though several other carrier board options exist.

The great thing about the SOM is that, with enough space and budget, you can simply place a SODIMM connector on a host board, saving time for designing peripherals and the larger product. This is helpful for two reasons. First, everything needed for the MPU to run is hosted on the SOM – just provide the main input power. Second, Toradex provides design files for their carrier boards, serving as a useful reference when debugging custom designs.

Technical Specs:

• Processor: NXP i.MX 6ULL @ 800MHz, based on ARM® Cortex®-A7 core
• Memory:
  • 4GB eMMC for long-term storage, MicroSD
  • 1GB DDR3L RAM for computing power
• Low-Level IO: SDIO, I2C, SPI, UART, PWM, GPIOs, CAN, USB
• Multimedia: Display – LVDS, HDMI, VGA, RGB; Audio – analog line in, analog mic in, analog headphone out
• Inputs: Resistive touch, Capacitive touch, Buttons, MIPI CSI camera port
• Connectivity: 10/100 Mb Ethernet, USB OTG
• Power: 7 – 27V DC into the terminal block, barrel jack, headed

#2: nRF52840 DK

The nRF52840, developed by Nordic Semiconductors, is really a stand-in for the entire nRF52 series. It’s a system-on-chip (SoC) that provides a robust development platform for BLE5.3 devices. It’s well supported by Zephyr RTOS and has an excellent low-power sleep mode, making it a great target for battery-powered devices. It can run on either a 1.8V or 3.3V power rail, and the nRF52840 DK includes a native coin cell battery. There are several perks associated with the  nRF52 series SoCs, but this dev kit in particular has a built-in JLink that can program and debug external nRF52 targets.

Technical Specs:

• Processor: Nordic Semiconductors nRF52840
• Memory: 
  • 1MB internal flash
  • 256kB internal RAM
• Low Level IO: I2C, SPI, UART, PWM, GPIOs, I2S, USB, ADC
• Multimedia: Audio – I2S
• Inputs: Buttons
• Connectivity: BLE5.3, NFC, USB OTG
• Power: USB connectors, headers, coin cell

#3: Discovery Kit with STMP32MP157A MPU

This board’s main draw is its  STM32MP157 microprocessor, which also supports embedded Linux development. One of its key differentiators is its dedicated 3D graphics processing unit (GPU) that powers the MIPI-attached LCD display with a touch panel. There’s even an audio codec for good measure.

The internal M4 MPU enables hard real-time and lower power modes. This board also offers Ethernet, Wi-Fi, and Bluetooth connectivity. Altogether, these features make this dev kit great for IoT devices that run user-facing applications.

Technical Specs:

• Processor: STM32MP157 ARM® dual Cortex®-A7 32-bit @ 800 MHz + Cortex®-M4 32-bit MPU @ 209 MHz
• Memory: 
  • MicroSD
  • 4Gbit DDR3L @ 533 MHz
• Low-Level IO: SDIO, I2C, SPI, UART, 12-bit ADC, PWM
• Multimedia: Display – MIPI DSI 4″ touch screen TFT 480×800 pixels; Audio – Codec
• Inputs: Buttons, Touch screen
• Connectivity: 1Gbps Ethernet, Wi-Fi, BLE 4.2, USB
• Power: 5V/ 3A USB Type-C power supply

#4: BeagleBone Green Gateway

Developed by Seeed Studio in conjunction with BeagleBoard.org, this OSHW shines for custom IoT gateway development. It’s pre-equipped with all of the necessary connectivity features — Ethernet, Wi-Fi, and Bluetooth Low Energy (BLE) — and includes two 32-bit programmable real-time units (PRUs) @ 200MHz.

Combined with the real-time Nerves functionality, this dev kit is perfect for Industrial Internet of Things (IIoT) applications that require extremely low latency for deterministic control. 

It also has ports for Seeed’s unique Grove sensors, which speeds up integration along with the standard BeagleBoard headers.

Technical Specs:

• Processor: AM3358 ARM® Cortext®-A8 @ 1 GHz with 2 32-bit PRUs @ 200 MHz
• Memory: 
  • 4GB eMMC, 4KB EEPROM, MicroSD
  • 4Gbit DDR3L @ 533 MHz
• Low-Level IO: SDIO, I2C, SPI, UART, 12-bit ADC, PWM
• Multimedia: Display – HDMI, LCD; Audio – Codec
• Inputs: Buttons, Touch screen
• Connectivity: 10/100 Mbps Ethernet, Wi-Fi, BLE 4.2, USB
• Power: 12V DC – Barrel Jack
• BeagleBone Expansion Headers
• Grove connectors 

#5: ESP32-S3-DevKitC-1

Another low-cost target is based on Espressif’s ESP32-S3-WROOM modules. They offer price points that are often hard to compete with, and the modules support both Wi-Fi and BLE. The documentation has improved as time goes on, and there’s quite a bit of support for ESP32s in Zephyr RTOS. It comes with either a built-in antenna or a u.FL connector for an external one.

Technical Specs:

• Processor: ESP32-S3-WROOM with Xtensa® 32-bit LX7 @ 240 MHz
• Memory: 
  • 128KB ROM, 4MB external SPI flash
  • 2MB PSRAM, 320KB SRAM, 16KB SRAM in RTC
• Low-Level IO: I2C, SPI, UART, ADC (not recommended to use), PWM
• Multimedia: Audio – I2S
• Inputs: Buttons
• Connectivity: Wi-Fi, BLE5, USB OTG, USB-UART bridge
• Power: MicroUSB, headers

#6: BeagleBone Black

The Black boasts a handful of attractive features for IoT development. Besides its open source status, we like to use the Black and Black Wireless simply because they perform well. Everything that was said about the BeagleBone Green holds true here — minus Ethernet + Wi-Fi/BT on a single board. 

Technical Specs:

• Processor: AM3358 ARM® Cortext®-A8 @ 1 GHz with 2 32-bit PRUs @ 200 MHz
• Memory: 
  • 4GB eMMC, 4KB EEPROM, MicroSD
  • 4Gbit DDR3L @ 533 MHz
• Low-Level IO: SDIO, I2C, SPI, UART, 12-bit ADC, PWM
• Multimedia: Display – HDMI, LCD; Audio – Codec
• Inputs: Buttons, Touch screen
• Connectivity: 10/100 Mbps Ethernet, Wi-Fi, BLE 4.2, USB
• Power: 5V DC – MicroUSB, Barrel Jack

#7: Raspberry Pi 4 Model B

While the popular Raspberry Pi (RPi) only provides limited schematics and design files, this SBC’s low price, common form factor, and general hackability earns it a place on our list. Letting an RPi run in the field — while developing the product on another dev kit — can generate swaths of insightful project data.

Raspberry Pi offers several options to choose from, including the RPi 4 with 2GB, 4GB, or 8GB of memory; the compute module 3+, which is easily designed as a system-on-module (SOM); and the RPi 0 2 W, which is less expensive and suited for less intensive applications.

Technical Specs (RPi4 B+):

• Processor: Broadcom BCM2711, Quad core ARM® Cortex®-A72 64-bit @ 1.5 GHz
• Memory: 
  • MicroSD
  • 2GB, 4GB, or 8GB LPDDR-3200 SDRAM
• Low-Level IO: I2C, SPI, UART, 12-bit ADC, PWM
• Multimedia: Display – 2x Micro HDMI, LCD; Audio – Codec
• Inputs: Buttons, Touch screen, MIPI CSI camera port
• Connectivity: 1 Gbps Ethernet, Wi-Fi, Bluetooth, USB 2.0 & 3.0
• Power: 5V USB-C, Power over Ethernet (PoE)

#8: Feather nRF52840 Express

This dev kit combines Adafruit’s Featherwing footprint with the versatility of Nordic Semiconductors’ nRF52840. The nRF52840-DK is somewhat bulky, but the Featherwing form factor is smaller and provides a wide range of “Feathers” for testing as direct plugins. This provides both OSHW and FW references that can help you kickstart your project.

If you’re looking to put together an early works-like prototype, you can always 3D print a case and solder the Featherwing to a sensor dev kit. 

Technical specs:

• Processor: Nordic Semiconductors nRF52840
• Memory: 
  • 1MB internal flash
  • 256kB internal RAM
• Low Level IO: I2C, SPI, UART, PWM, GPIOs, I2S, USB, ADC
• Multimedia: Audio – I2S
• Inputs: Buttons
• Connectivity: BLE5.3, USB OTG
• Power: USB connector, headers, Li-Po battery + charger

#9: EVB 2.0 Module Evaluation & IoT Device Development Kit

In certain cases, you won’t always be interested in a target MCU or MPU. Instead, you’ll need to evaluate a new Wi-Fi or cellular module. The Telit EVB 2.0 allows just that, providing a prototyping platform that facilitates connections with several of their target radios. 

For example, the ME910 NB-IoT/Cat-M1 cellular module with GNSS support can be connected directly to a BeagleBone host port. Within a few hours, you’ll be up and running with cellular connectivity.

In many situations, the MCU/MPU target dev kit may not have Wi-Fi/BLE on board, and you might want to evaluate the WE866C6 dual-band Wi-Fi module. One option includes using the EVB2.0 to host the WE866C6-P Wi-Fi EVK, which has an SD card form factor for the SDIO interface, and then connecting via USB and a combination of jumpers. Not only are their current modules supported, but Telit aims to build future dev kits that can interface with EVB 2.0. Having a familiar platform to prototype with can make a world of difference in speeding up your next design.

Your Agile IoT Project

The right IoT dev kit is the heart of any Agile IoT project. By choosing an IoT board from this top 10 list for your project, you can cut costs, reduce time to market, and build in more of the features you’ve been looking to incorporate.

• Connectivity
• Hardware Components
• IoT Platforms

• Connectivity
• Hardware Components
• IoT Platforms