There’s a lot of undeserved love in the maker community for the Adruino Uno R3. And there’s a lot of unearned hate in the electronics engineering community for it as well. The ATMega328U is a low-powered microcontroller and the layout of the Arduino R3 breaks almost every conceivable routing best-practice that exists. Yet non of that really matters. The platform, with its Integrated Development Environment, ubiquitous support, numerous shields, and well-written libraries from distributors such as Adafruit and SparkFun can solve a hundred engineering problems in five minutes or less. Need an I2C interface for a sensor you’re considering using? No problem. Need a quick and dirty analog data logger to monitor battery voltages as it discharges? Or a UART GPS logger? Or any of a myriad of other things? The Arduino Uno platform makes the ATMega328U the swiss army knife of microcontrollers — It doesn’t do anything particularly well, but it does everything well enough that you can avoid getting a different tool out. I probably have ten of them squirreled away in my office.
But if a simple microcontroller isn’t enough for you — you can upgrade to a complete operating system in the Raspberry Pi. In the Pi, you have a full Linux operating system at your disposal. At the low end of their offerings, and for the paltry sum of $10, you get a 1GHz microprocessor with 512 MB of RAM, Wifi, Bluetooth, HDMI, and a few other bells and whistles that can augment the 30 or so GPIO pins on the header. And if you don’t need the wireless capability, the price is cut in half to only $5! Between the Raspberry Pi 2, 3, 4, and Zero models, I probably have another ten attached to various projects. And now that the Pico is out, my ownership numbers are only going to go up.
It makes sense to own these as tools even if all they do is sit on the workbench for prototyping and testing purposes. But there are times when it also makes sense to incorporate these devices directly into your projects. For example, if you have a small-run industrial automation project that needs WiFi capability, data logging, and perhaps communication with a few wired peripherals, you’re really supposed to get FCC part 15 certification for your design. FCC radio certification costs $4-5000, you’d still need to source parts and find and program a design. That means it’s cheaper for you to just buy a populated $10 pre-certified module up to around 1-2000 units. Granted, you can find cheaper wireless modules out there that lower the break-even number quite a bit, but don’t forget to include your time doing schematic design, board layout, navigating the certification process, learning to program and work with the firmware, etc… In short, for short runs of certain projects, it makes sense to just use the Raspberry Pi Zero Wireless as the entire basis of your project and utilize their certificates of conformity. And what’s more, the package maintainers will handle device security for you, so all you’ll have to do is set a cron task to install nightly or weekly security updates.
But don’t stop there — if you need even more horsepower, there’s the Raspberry Pi 4, the computer modules, NVidia’s Jetson Nano that excels in machine learning, the BeagleBone, and more. Keep the Commercial-Off-The-Shelf designs in mind before you set off on your next Bespoke design.