In Praise Of “Simple” Projects

January 27, 2024 by Elliot Williams 9 Comments

When I start off on a “simple” project, experience shows that it’s got about a 10% chance of actually remaining simple. Sometimes it’s because Plan A never works out the way I think it will, due to either naivety or simply the random blockers that always get in the way and need surmounting. But a decent percentage of the time, it’s because something really cool happens along the way. Indeed, my favorite kind of “simple” projects are those that open up your eyes to a new world of possibilities or experiments that, taken together, are nothing like simple anymore.

Al Williams and I were talking about water rockets on the podcast the other day, and I realized that this was a perfect example of an open-ended simple project. It sounds really easy: you put some water in a soda bottle, pressurize it a bit with air, and then let it go. Water gets pushed down, bottle flies up. Done?

Oh no! The first step into more sophistication is the aerodynamics. But honestly, if you make something vaguely rocket-shaped with fins, it’ll probably work. Then you probably need a parachute release mechanism. And then some data logging? An accelerometer and barometer? A small video camera? That gets you to the level of [ARRO]’s work that spawned our discussion.

But it wasn’t ten minutes into our discussion that Al had already suggested making the pressure vessel with carbon fiber and doctoring the water mix to make it denser. You’d not be surprised that these and other elaborations have been tried out. Or you could go multi-stage, or vector-thrust, or…

In short, water rockets are one of those “simple” projects. You can get one basically working in a weekend day, and then if you’re so inclined, you could spend an entire summer of weekends chasing down the finer points, building larger and larger tubes, and refining payloads. What’s your favorite “simple” project?

Hardware Should Lead Software, Right?

January 20, 2024 by Elliot Williams 26 Comments

Once upon a time, about twenty years ago, there was a Linux-based router, the Linksys WRT54G. Back then, the number of useful devices running embedded Linux was rather small, and this was a standout. Back then, getting a hacker device that wasn’t a full-fledged computer onto a WiFi network was also fairly difficult. This one, relatively inexpensive WiFi router got you both in one box, so it was no surprise that we saw rovers with WRT54Gs as their brains, among other projects.

Of course, some people just wanted a better router, and thus the OpenWRT project was born as a minimal Linux system that let you do fancy stuff with the stock router. Years passed, and OpenWRT was ported to newer routers, and features were added. Software grew, and as far as we know, current versions won’t even run on the minuscule RAM of the original hardware that gave it it’s name.

Enter the ironic proposal that OpenWRT – the free software group that developed their code on a long-gone purple box – is developing their own hardware. Normally, we think of the development flow going the other way, right? But there’s a certain logic here as well. The software stack is now tried-and-true. They’ve got brand recognition, at least within the Hackaday universe. And in comparison, developing some known-good hardware to work with it is relatively easy.

We’re hardware hobbyists, and for us it’s often the case that the software is the hard part. It’s also the part that can make or break the user experience, so getting it right is crucial. On our hacker scale, we often choose a microcontroller to work with a codebase or tools that we want to use, because it’s easier to move some wires around on a PCB than it is to re-jigger a software house of cards. So maybe OpenWRT’s router proposal isn’t backwards after all? How many other examples of hardware designed to fit into existing software ecosystems can you think of?

New Year’s Resolutions

January 6, 2024 by Elliot Williams 18 Comments

As we stand here looking at the brand-new year ahead, we find ourselves taking stock, and maybe thinking how we can all be better people in the next year. More exercise, being nicer to your neighbors, consuming more or less of this or that, depending on whether it’s healthy or un. Those are the standard fare. But what’s your hacker new year’s resolution?

Mine, this year, is to branch out into a new microcontroller family, to learn a new toolchain, and maybe to finally dip my toes into Bluetooth Low Energy. Although that last one is admittedly a stretch.

But the former is great resolution material, if you allow me. New programming tooling is always a little unpleasant to set up, but there’s also payoff at the end of the ordeal. It’s a lot like picking up a new exercise – it makes you stronger. Or course, it helps to have an application in mind, the equivalent of that suit you want to be able to fit into at the end of the diet. I’ve got one. I’ve also been out of programming in straight C for a year or so, and I’m faced with a new HAL, so there’s bound to be enough of a challenge to make it worthwhile.

Honestly, I’m looking forward to getting started, but with the usual mix of optimism, over-optimism, and mild dread. It’s the perfect setup for a resolution! What’s yours?

(And yes, the art is from another story, but setting up a good backup regime isn’t a bad resolution either.)

You Can’t Make What You Can’t Measure

December 16, 2023 by Elliot Williams 30 Comments

What’s the most-used tool on your bench? For me, it’s probably a multimeter, although that’s maybe a tie with my oscilloscope. Maybe after that, the soldering iron and wire strippers, or my favorite forceps. Calipers must rate in there somewhere too, but maybe a little further down. Still, the top place, and half of my desert-island top-10, go to measuring gear.

That’s because any debugging, investigation, or experimentation always starts with getting some visibility on the problem. And the less visible the physical quantity, the more necessary to tool. For circuits, that means figuring out where all the voltages lie, and you obviously can’t just guess there. A couple months ago, I was doing some epoxy and fiberglass work, and needed to draw a 1/2 atmosphere vacuum. That’s not the kind of quantity you can just eyeball. You need the right measurement tool.

A few weeks ago, I wrote about my disappointment in receiving a fan that wouldn’t push my coffee beans around in the homemade roaster. How could I have avoided this debacle? By figuring out the pressure differential needed and buying a fan that’s appropriately rated. But I lacked pressure and flow meters.

Now that I think about it, I could have scavenged the pressure meter from the fiberglassing rig, and given that a go, but with the cheap cost of sensors and amplifiers, I’ll probably just purpose-build something. I’m still not sure how I’ll measure the flow; maybe I’ll just cheese out and buy a cheap wind-speed meter.

When people think of tools, they mostly think of the “doers”: the wrenches and the hammers of this world. But today, let’s all raise a calibrated 350 ml glass to the “measurers”. Without you, we’d be wandering around in the dark.

Degrees Of Freedom, But For Whom?

December 9, 2023 by Elliot Williams 48 Comments

Opening up this week’s podcast, I told Kristina about my saga repairing our German toilet valve. I’m American, and although I’ve lived here over a decade, it’s still surprising how things can be subtly different from how they worked back home.

But what was amazing about this device was that it had a provision for fine adjustment, and to some extent relied on this adjustment to function. Short version: a lever mechanism provides mechanical advantage to push a stopper against the end of a pipe to block the water flow, and getting the throw of this mechanism properly adjusted so that the floater put maximum pressure against the pipe required fine-tuning with a screw. But it also required understanding the entire mechanism to adjust it.

Which makes me wonder how many plumbers out there actually take the time to get that right. Are there explicit instructions in the manual? Does every German plumber learn this in school? I was entirely happy to have found the adjustment screw after I spent 15 minutes trying to understand the mechanism, because it did just the trick. But is this everyone’s experience?

I often think about this when writing code, or making projects that other people are likely to use. Who is the audience? Is it people who are willing to take the time to understand the system? Then you can offer them a screw to turn, and they’ll appreciate it. But if it’s an audience that just doesn’t want to be bothered, the extra complexity is just as likely to cause confusion and frustration.