Tinkerer’s Closet – Selecting hardware

Posted: February 23, 2024 | Author: | Filed under: Computicle, Core Programming, Hardware, Musings | Tags: , , , , , , , , , | Leave a comment

Well, there’s no better reason to clean out your closet or workspace, than to fill it with new stuff!! I’ve been spending a fair amount of time cleaning out the old stuff, and I’ve gotten far enough along that I feel it’s safe to poke my head up and see what’s new and exciting in the world of hardware components today.

What to look at though, so I don’t just fill up with a bunch more stuff that doesn’t get used for the next 10 years? Well, this time around I’m going project based. That means, I will limit my searching to stuff that can help a project at hand. Yes, it’s useful to get some items just for the learning of it, but for a hoarder, it’s better to have an actual project in mind before making purchases.

On the compute front, I’ve been standardizing the low end around ESP 32 modules. I’ve mentioned this in the past, but it’s worth a bit more detail. The company, Espressif, came along within the past decade, and just kind of took the maker community by storm. Low cost, communications built in (wifi, bluetooth), capable processors (32-bit). They are a decent replacement at the low end of things, taking the place of the venerable Arduino, which itself was a watershed in its day.

The keen thing about the Espressif modules is how programmable they are. You can use the Aruino IDE, or PlatformIO (tied to Visual Studio), or their standalone IDE. You can program it like a single CPU with full control of everything, or you can run a Real-time OS (FreeRTOS) on it. This makes it super easy to integrate into anything from simple servo motor control, to full on robotics.

As for form factor, I’m currently favoring the Adafruit ‘feather’ forms. The ‘feather’ form factor is a board specification, which puts pins in certain locations, regardless of which actual processor is on the board. This makes it a module that can be easily integrated into designs, because you have known patterns to build around. I have been using the ESP32 Feather V2 primarily.

It’s just enough. USB-C connector for power, and programming. Battery connector for easy deployment (battery charges when USB-C is plugged in). STEMMA QT connector (tiny 8 pin connector) for easy I2C connection of things like joysticks, sensors, anything on the I2C bus. Antenna built in (wifi/bluetooth radio on the right, with black PCB antenna next to it).

It’s just a handy little package, and my current best “computicle”. You can go even smaller, and get ESP 32 modules in different packages, but this is the best for prototyping in my lab.

As an aside, I want to mention Adafruit, the company, as a good source for electronic components. You can checkout their about page to get their history. Basically, they were created in 2005, and have been cranking out the hits in the maker space ever since. What attracted me to them initially was their tutorials on the components they sell. They have kits and tutorials on how to solder, as well as how to integrate motors into an ESP 32 design. Step by step, detailed specs, they’re just good people. They also pursue quality components. I mean, every USB cable is the same right? Nope, and they go through the myriad options, and only sell the best ones. So, if you’re in the market, check them out, at least for their tutorials.

Going up the scale from here, you have “Single Board Computers”. The mindshare leader in this space is definitely the Raspberry Pi. When they sprung onto the scene, there really wasn’t any option in the sub-$50 range. Since then (2006ish), there has been an entire renaissance and explosion of single board computers. They are typically characterized by: Arm based processor, 4-8Gb RAM, USB powered, HDMI output, a couple of rows of IO pins, running Linux (Ubuntu typically).

I’ve certainly purchased my share of Raspberry Pi boards, and variants. I tend to favor those coming from Hard Kernel. I find their board innovations over the years to be better than what the Pi Foundation is typically doing. Also, they are more readily available. Hard Kernel has commercial customers that use their boards in embedded applications, so they tend to have Long Term Support for them. They have boards based on ARM typically, meant to run Linux, but they also have Windows based boards as well.

Here’s a typical offering,

The Odroid M1S.

The one thing that’s critical to have in a single board computer is software support. There are as many single board computers available in the world as there are grains of sand on a beach. What differentiates them is typically the software support, and the community around it. This is why the Raspberry Pi has been so popular. They have core OS support, and a super active community that’s always making contributions.

I find the Odroid boards to be similar, albeit a much smaller community. They do have core OS support, and typically get whatever changes they make integrated into the mainline Linux development tree.

This M1S I am considering as a brain for machines that need more than what the ESP32 can handle. A typical situation might be a CNC machine, where I want to have a camera to watch how things are going, and make adjustments if things are out of wack. For example, the camera sees that the cutting bit has broken, and will automatically stop the machine. Or, it can see how the material is burring or burning, and make adjustments to feeds and speeds automatically.

For such usage, it’s nice to have the IO pins available, but communicating over I2C, CANBus, or other means, should be readily available.

This is reason enough for me to purchase one of these boards. I will look specifically for pieces I can run on it, like OpenCV or some other visual module for the vision stuff. I have another CNC router that I am about to retrofit with new brains, and this could be the main brain, while the ESP32 can be used for the motor control side of things.

Last is the dreamy stuff.

The BeagleV-Fire

This is the latest creation of BeagleBoard.org. This organization is awesome because they are dedicated to creating “open source” hardware designs. That’s useful to the community because it means various people will create variants of the board for different uses, making the whole ecosystem more robust.

There are two special things about this board. One is that it uses a RISC-V chip, instead of ARM. RISC-V is an instruction set, which itself is open source, and license free. It is a counter to the ARM chips, which have license fees and various restrictions. RISC-V in general, will likely take up the low end of the market for CPU processors in all sorts of applications that typically had ARM based chips.

The other feature of these boards is onboard integrated FPGA (Field Programmable Gate Array). FPGA is a technology which makes the IO pins programmable. If you did not have a USB port, or you wanted another one, you could program some pins on the chip to be that kind of port. You can even program a FPGA to emulate a CPU, or other kinds of logic chips. Very flexible stuff, although challenging to program.

I’ve had various FPGA boards in the past, and even ones that are integrated with a CPU. This particular board is another iteration of the theme, done by a company that has been a strong contributor in the maker community for quite some time.

Why I won’t buy this board, as much as I want to; I don’t have an immediate need for it. I want to explore FPGA programming, and this may or may not be the best way to learn that. But, I don’t have an immediate need. Getting an Odroid for creating a smarter CNC makes sense right now, so one of those boards is a more likely purchase in the near term. It might be that in my explorations of CNC, I find myself saying “I need the programmability the BeagleBone has to offer”, but it will be a discovery based on usage, rather than raw “I want one!”, which is a departure from my past tinkerings.

At this point, I don’t need to explore above Single Board computers. They are more than powerful enough for the kinds of things I am exploring, so nothing about rack mountable servers and kubernetes clusters.

At the low end, ESP32 as my computicles. At the high end, Hard Kernel based Single Board Computers for brains.