First Days With A New Microscope

For big-ticket purchases, I tend to do a lot of research before I open my wallet. I like to at least have the illusion that when I send my money off to a far-away stranger, I’m likely to get back something of equal value in a reasonable timeframe that does what I want it to do. So I tend more toward the “analysis paralysis” end of the spectrum, where I pore over so many specs and reviews that I end up buying nothing.

While that sounds like a bad thing, and sometimes is, I find that it tends to help me avoid rashly spending money on things that aren’t going to work for me. This is especially true in the area of tools, where while I’m trapped in my analysis loop, I often find a workaround or substitute that’s good enough to get the job done.

For some things, though, there is no substitute, and when you start working with SMD components that you’d have a hard time telling from a grain of salt, you’re probably going to need a microscope. I recently determined that this was where I was in my electronics journey, and now that I’ve worked my way through the analysis and procurement phase of the process, I thought I’d share my first impressions of my microscope, and what it’s like to get used to working with one.

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A graph visualising approximation errors - the specific principle pictured is described well by the linked article

Time And Accuracy In Las ATMegas

Do you ever have to ensure that an exact amount of time passes between two tasks in your microcontroller code? Do you know what’s the difference between precision and accuracy? Today, [Jim Mack] tells us about pushing timers and interrupts to their limits when it comes to managing time, while keeping it applicable to an ever-popular ATMega328P target! Every now and then, someone decides to push the frontiers of what’s possible on a given platform, and today’s rules is coding within constraints of an Arduino environment. However, you should check [Jim]’s post out even if you use Arduino as a swearword – purely for all of the theoretical insights laid out, accompanied by hardware-accurate examples!

This will be useful to any hacker looking to implement, say, motor encoder readings, signal frequency calculations, or build a gadget processing or modifying audio in real time. To give you a sample of this article, [Jim] starts by introducing us to distinctions between precision and accuracy, and then presents us with a seemingly simple task – creating exactly 2400 interrupts a second. As much as it might look straightforward, problems quickly arise when clock crystal frequency doesn’t cleanly divide by the sampling frequency that you have to pick for your application! This is just a taste of all the examples of hidden complexity presented, and they’re accompanied with solutions you can use when you eventually encounter one of these examples in your hacker pursuits. In the end, [Jim] concludes with links to other sources you can study if you ever need to dig deeper into this topic.

Keeping our projects true to the passage of time can be an issue, and we’ve been at it for ages – calibrating your RC oscillator is a rite of passage for any ATTiny project. If you ever decide to have an interrupt peripheral help you with timing issues, we’ve gone in-depth on that topic in the past, with a three-part series describing the benefits, the drawbacks and the edgecases of interrupts. Going for a more modern target? Our piece on using interrupts with STM32 is a great path for trying out tools of the modern age.

Back of Rigol DS1104Z oscilloscope with the Ethernet and USB ports visible.

SCPI: On Teaching Your Devices The Lingua Franca Of Laboratories

One could be excused for thinking sometimes that the concept of connecting devices with other devices for automation purposes is a fairly recent invention. Yet for all the (relatively) recent hype of the Internet of Things and the ‘smart home’, laboratories have been wiring up their gear to run complicated measurement and test sequences for many decades now, along with factories doing much the same for automating production processes.

Much like the chaotic universe of IoT devices, lab equipment from different manufacturers feature a wide number of incompatible protocol and interface standards. Ultimately these would coalesce into IEEE-488.1 (GPIB) as the physical layer and by 1990 the first Standard Commands for Programmable Instruments (SCPI) standard was released that built on top of IEEE-488.

SCPI defines (as the name suggests) standard commands to interact with instruments. It has over the past decades gone on to provide remote interaction capabilities to everything from oscilloscopes and power supplies to exotic scientific equipment. Many off the shelf devices a hobbyist can buy today feature an SCPI interface via its Ethernet, USB or RS-232C port(s) that combined with software can be used to automate one’s home lab.

Even better is that it’s relatively straightforward to add SCPI functionality to one’s own devices as well, so long as it has at least an MCU and some way to communicate with the outside world.

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Linux Fu: Automatic Header File Generation

I’ve tried a lot of the “newer” languages and, somehow, I’m always happiest when I go back to C++ or even C. However, there is one thing that gets a little on my nerves when I go back: the need to have header files with a declaration and then a separate file with almost the same information duplicated. I constantly make a change and forget to update the header, and many other languages take care of that for you. So I went looking for a way to automate things. Sure, some IDEs will automatically insert declarations but I’ve never been very happy with those for a variety of reasons. I wanted something lightweight that I could use in lots of different toolsets.

I found an older tool, however, that does a pretty good job, although there are a few limitations. The tool seems to be a little obscure, so I thought I’d show you what makeheaders — part of the Fossil software configuration management system. The program dates back to 1993 when [Dwayne Richard Hipp] — the same guy that wrote SQLite — created it for his own use. It isn’t very complex — the whole thing lives in one fairly large C source file but it can scan a directory and create header files for everything. In some cases, you won’t need to make big changes to your source code, but if you are willing, there are several things you can do.

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Basics Of Remote Cellular Access: Watchdogs

When talking about remote machines, sometimes we mean really remote, beyond the realms of wired networks that can deliver the Internet. In these cases, remote cellular access is often the way to go. Thus far, we’ve explored the hardware and software sides required to control a machine remotely over a cellular connection.

However, things can and do go wrong. When that remote machine goes offline, getting someone on location to reboot it can be prohibitively difficult and expensive. For these situations, what you want is some way to kick things back into gear, ideally automatically. What you’re looking for is a watchdog timer!

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Need A New Programming Language? Try Zig

Maybe you’ve heard of it, maybe you haven’t. Zig is a new programming language that seems to be growing in popularity. Let’s do a quick dive into what it is, why it’s unique, and what sort of things you would use it for. (Ed Note: Other than “for great justice“, naturally.)

What Is It?

You’ve likely heard of Rust as it has made significant inroads in critical low-level infrastructures such as operating systems and embedded microcontrollers. As a gross oversimplification, it offers memory safety and many traditional runtime checks pushed to compile time. It has been the darling of many posts here at Hackaday as it offers some unique advantages. With Rust on the rise, it makes sense that there might be some space for some new players. Languages like Julia, Go, Swift, and even Racket are all relative newcomers vying for the highly coveted mindshare of software engineers everywhere.

So let’s talk Zig. In a broad sense, Zig is really trying to provide some of the safety of Rust with the simplicity and ease of C. It touts a few core features such as:

  • No hidden control flow
  • No hidden memory allocations
  • No preprocessor, no macros
  • First-class support for optional standard library
  • Interoperable by design
  • Adjustable Runtime Safety
  • Compile-time code-execution

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Troubleshooting: A Method For Solving Problems The Right Way

We’ve all experienced that magic moment when, after countless frustrating hours of experimentation and racking your brain, the object of our attention starts working. The 3D printer finally produces good output. The hacked up laptop finally boots. The car engine finally purrs. The question is, do we know why it started working?

This is more important than you might think. Knowing the answer lets you confirm that the core problem was solved, otherwise you may have just fixed a symptom. And lack of understanding means fixing one problem may just create another.

The solution is to adopt a methodical troubleshooting method. We’re talking about a structured problem solving technique that when used properly can help us solve a problem at its core without leaving any loose ends. Such methodology will also leave you knowing why any solution did or didn’t work in the end, and will give you reproducible results.

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