Get Yer Halloween On!

October 2, 2021 by Elliot Williams 3 Comments

Halloween is basically built for the hacker. Besides the obvious fabrication of absurd costumes, there’s also the chance to showcase your skills, be they mechanical, audio, or video. It’s also a great time to show off our coolest tricks to inspire the young proto-hackers. If you need inspiration, we’ve got 150 ideas.

My personal problem with Halloween, though, is that I always start at the last minute, and my ideas far outreach my time budget. Or because it’s all done in the last minute, a whole bunch of ideas that should “just work” in theory run into the immovable object that is practice. At least that’s what happened with last year’s spooky sound effects — my son and I spent so much time collecting and recording scary audio samples that I ran out of time while still getting the sensitivity on the motion detector set just right, and then the battery died halfway through the night.

But this year will be different, I swear! I’m going to get it done early and test it out, with the luxury of time to debug the inevitable spiders. And you can swear too. Get started now on your Halloween project. Or at least next weekend.

What’s your favorite Halloween Hack?

Contests

If you need any more encouragement to fire up your black and orange hacking machine, think of Hackaday.io’s Halloween Hackfest. It runs until Oct 28, and all you have to do to enter is document your Halloween project on IO and press the “Submit” button. The deadline is the 28th, which still gives you a couple of nights to debug whatever didn’t work before the real deal. Prizes are shopping sprees at Digi-Key, and Adafruit is doubling the gift certificate if you use any Adafruit parts in the build.

If you don’t give a pumpkin about stupid ol’ Halloween, that’s cool too. (Grinch!) The 2021 Hackaday Prize has entered the final wildcard round. If your project didn’t fit in any of the previous categories, I’m pretty sure it’ll fit just fine in the anything-goes phase. Go nuts. We’d love to see what you’re working on.

Embrace The New, But Don’t Forget The Old

September 25, 2021 by Elliot Williams 36 Comments

We were trading stories of our first self-made PCBs in the secret underground Hackaday bunker, and a couple of the boards looked really good for first efforts. Of course there were mistakes and sub-optimal routing, but who among us never connects up the wrong signals or uses a bad footprint? What lead me to have a hacker “kids these days have it so easy” moment was that all of the boards were, of course, professionally fabbed with nice silkscreens. They all looked great.

What a glorious time to be starting down the hardware path! When I made my first PCB, the options were basically laying down tape, pulling out the etch resist pen, or paying a bazillion inflation-adjusted dollars for a rapid prototype board. This meant that the aspiring hacker also had to have a steady hand and be at least casually acquainted with a little chemistry. The ability to just send your files out to a PCB house means that the barrier to stepping up your hardware game from plug-them-together modules is lower than it’s ever been.

But if scratching or etching your own PCB out of copper plate is very hands-on, very DIY, and very low-tech, it’s also very fast in comparison to even the most rushed service. Last weekend, I needed a breakout board for some eight-pin SOIC H-bridge chips for a turtle robot project with my son. Everything was hand-soldered and hot-glued in a Saturday afternoon and evening, so there was no time for a PCB order. A perfect opportunity for the Old Ways™.

We broke out a Sharpie, traced out where the SOIC pins would land, connected up the grounds, brought the signals out to friendly pads, and then covered the rest of the board in islands of copper just in case we’d need any prototyping space later. Of course, some of the ink lines touched each other where they shouldn’t, but before the copper meets the etchant it’s easy enough to scrape the spaces clear with a pin. The results? My boards look like they were chiseled out by a caveman, but they worked. And more importantly, we got it done within the attention span of a second grader without firing up a computer.

So revel in your cheap offshore PCB factories, hackers of today! It’s a miracle that even four-layer boards come back within a week without breaking the bank. But I encourage you all to try it out by hand as well. For large enough packages and one-offs, full DIY absolutely has the speed advantage, but there’s also a certain wabi sabi to the hand-drawn board. Like brush strokes in residual copper.

Finding The Right Hack Is Half The Battle

September 18, 2021 by Elliot Williams 25 Comments

Sometimes you just get lucky. I had a project on my list for a long time, and it was one that I had been putting off for a few months now because I loathed one part of what it entailed — sensitive, high-accuracy analog measurement. And then, out of the blue I stumbled on exactly the right trick, and my problems vanished in thin air. Thanks, Internet of Hackers!

The project in question is a low-vacuum regulator for “bagging” fiberglass layups. What I needed was some way to read a pressure sensor and turn on and off a vacuum pump accordingly. The industry-standard vacuum gauges are neat devices, essentially a tiny little strain gauge on a membrane between the vacuum side and the atmosphere side, in a package the size of a dime. (That it’s a strain gauge is foreshadowing, but I didn’t know that at the time.) I bought one for $15 ages ago, and it sat on my desk, awaiting its analog circuitry.

See, the MPX2100 runs on 12 V and puts out a signal around 40 mV on top of a 6 V offset. That voltage level is inconvenient for modern 3.3 V microcontroller ADCs, and the resolution would get clobbered by the 6 V signal if I just put a voltage divider on it. This meant whipping together some kind of instrument amplifier circuit to null out the 6 V and amplify the 40 mV for the ADC. The circuits I found online all called for 1% resistors in values I didn’t have, and mildly special op-amps. No fun, for me at least. So there it sat.

Picture of sketchy-looking vacuum apparatus. — Cut the blue wire or the red wire? HX711 module and pressure sensor on the left.

Until I ran into this project that machetes through the analog jungle with one part, and it happened to be one I had on hand. A vacuum pressure sensor is a strain gauge, set up like a Wheatstone bridge, just like you would use for weighing something with a load cell. The solution? A load-cell ADC chip, the HX711, found in every cheap scale or online for under a buck. The only other trick was finding a low-voltage pressure sensor to work with it, but that turns out to be easy as well, and I had one delivered in two days.

In all, this project took months of foot-dragging, but only a few clicks and five minutes of soldering once I got the right idea. The industrial applications and manufacturers’ app notes all make sense if you are making hundreds or millions of these devices, where the one-time cost of prototyping up the hard bits gets amortized, but the hacker solution of using a weight-scale chip was just the ticket for a one-off. That just goes to show how useful sharing our tips and tricks can be — you won’t get this from the industry. So send us your success stories, and your useful failures too, and Read More Hackaday!

Getting Back Into Hackerspaces

September 4, 2021 by Elliot Williams 14 Comments

Last week, I got my first chance to get out and about among the hackers in what feels like forever. Hackerspaces here in Germany are finally able to re-open for business-as-almost-usual, allowing access to reasonable numbers of people providing they’re immunized or tested, and wearing masks of course. And that meant that I got to take up [Andreas’] invitation to come see his Stereo Ninja inspection microscope project in person.

Stereo Ninja basically makes clever use of two Raspberry Pi cameras, swaps out the optics for greater enlargement, and displays the results on a 3D monitor — to be viewed with shutter glasses. This is one of those projects that you really have to see in person to “get it”. He’s still working on stripping the build down to make it simpler and more affordable, to make the project more accessible to the average hacker.

We talked about DIYing a 3D monitor. It turns out that the shutter glasses are cheap, and it looks like they’re synced by an IR pulse to the monitor. There should be a hacker solution for 3D to work with a fast gaming monitor at least. [Andreas] also pointed me to this great breakout board for the Raspberry Pi CM4 that breaks out both camera lanes for easy stereo / 3D capture. I got the tour of the FabLab, and we talked welding, metal 3D printing, software, hardware and assorted nerdy stuff. [Alex] showed up on his way out of town for the weekend — it’d been ages since we hung out.

In short, I remembered how it used to be in the before-times, when visits with other hackers, and to other hackerspaces, were possible. There’s this spontaneous and mutually inspirational kind of chat that’s just impossible remotely, and is tremendously important.

We’re not done with the COVID pandemic yet, I fear, and different parts of the world have entirely different trajectories. If you told me two years ago that I would be visiting hackerspaces with a mask and proof-of-vaccination, I would have thought you were crazy. But at the same time this brief visit gave me a little boost of hope for the future. We will get through all of this, and we’ll all meet up again at our local hackerspaces.

Who Owns The Machine Anyway?

August 28, 2021 by Elliot Williams 42 Comments

The story of the McDonalds’ frozen treat machine involves technology, trade secrets, inside business dealings, franchiser/franchisee friction, and an alleged NDA violation. In short: lots of money and lawyers. But it also involves something that matters to all of us hackers — what it means to own a machine.

The brief background is that McDonald’s requires its franchisees to buy a particular Taylor Soft Serve machine. The machine would enter pasteurizing mode and has opaque error codes that are triggered apparently without the owners or operators understanding, at which point Taylor service techs come in to fix them — and get paid for their service, naturally. A small hardware startup, Kytch, stepped into the mess with a device that man-in-the-middles the Taylor machine’s status codes, allowing the machine’s owners to diagnose and monitor it themselves. Heroes, right?

Taylor, naturally, wants to look at a Kytch device, but they’re locked up under NDAs that Kytch require users to sign in order to protect their trade secrets. So when Taylor gets their hands on one, Kytch takes them to court for, ironically, reverse engineering their device that they built to reverse Taylor’s protocols.

There are no good guys in this fight: it’s corporate secrecy fighting corporate secrets. None of which, by the way, is Hackaday particularly fond of. Why? Because these secrets rob the ostensible owners of the devices of their ability to inspect, fix, and operate their machines. This is akin to the “right to repair” idea, but it’s somehow even more fundamental — the right to know what your own devices are doing.

What this story needs is a Robin Hood. And as the devices we get sold become increasingly wrapped up in EULAs and NDAs, and full of secret sauce that’s out of our control, we’re going to need a lot more Robin Hoods. It’s McDonald’s frozen treat machines, but it’s also your smart thermostat and your inkjet printer and your — you name it. Have at it, Hackaday!

Robot Utopia

We see so many dystopian visions of automation, it’s time for us to do it right! The Redefine Robots round of the 2021 Hackaday Prize just started, and it’s your chance to build robots that respect the users. It doesn’t have to be the largest project in the world, but it does have to be automatic and helpful. Start your engines!

Keep Scraps Around

August 21, 2021 by Elliot Williams 30 Comments

When I’m building something, I like to have a decent-sized scrap pile on hand. Because when I’ve got to test something out — does this glue adhere to this fabric, how much force will this hold if I tap it and put a screw in, will it snap if reinforced with carbon fiber and epoxy — it’s nice to have some of the material in question on hand just for experimentation. So I pull a chunk out of the scrap pile!

But scrap piles can’t expand forever, and we all know that “too much of a good thing” is a thing, right? Scrap piles require constant pruning. You don’t really need more than a few aluminum extrusion cutoffs, so when you start building up excess inventory, it’s time to scrap it. I mean, throw it away.

A corollary of this, that I’ve only recently started to appreciate, is that if I limit the number of materials that I’m working with, it’s a lot more manageable to keep the scrap pile(s) under control. It’s simple math. If I’m working with twenty different materials, that’s twenty different heaps of scrap. But if I can get by with one weight of fiberglass for everything, that one pile of scraps can do double or triple duty. There is also the added benefit that I already know how the material works, and maybe even have old test samples on hand.

Indeed, I’m such a scrapaholic that it’s almost painful to start working with a new material and not have a scrap pile built up yet. I’m always loathe to cut into a nice square piece of stock just to test something out. But this too is part of the Great Circle of Life. By not testing things out beforehand, I’m almost guaranteed to screw up and create scrap out of what I had hoped was going to be a finished piece. See? No problem! Next version.

What do you think? Are scrap, offcuts, and their close cousins — test pieces and samples — worth keeping around in your shop? Do you have a disciplined approach, or do you just throw them in the corner? Purge per project, or only when the mountain of XPS foam gets as high as your head?

Goals And Goalposts

August 14, 2021 by Elliot Williams 14 Comments

In the winter, I hatched a vague plan to learn some of the modern unmanned aerial vehicle tech. Everybody needs an autonomous vehicle, and we’ve got some good flying fields within walking distance, so it seemed like it could work. Being me, that meant buying the cheapest gear that could possibly work, building up the plane by myself, and generally figuring out as much as possible along the way. I learn more by making my own mistakes anyway. Sounds like a good summer project.

Fast-forward to August, and the plane is built, controller installed, and I’ve spent most of the last month trying to make them work well together. (The firmware expects a plane with ailerons, and mine doesn’t have them, but apparently I’d rather tweak PID values than simply add a couple wing servos.) But it’s working well enough that it’s launching, flying autonomous waypoint missions, and coming home without any intervention. So, mission accomplished, right?

Nope. When I’m enjoying a project, I have a way of moving the goalposts on myself. I mean, I don’t really want to be done anyway. When a friend asked me a couple weeks ago what I was planning to do with the plane, I said “take nice aerial videos of that farm over there.” Now I see flight opportunities everywhere, and need to work on my skills. The plane needed an OLED display. It probably still needs Bluetooth for local configuration as well. Maybe a better long-range data link…

This is creeping featurism and moving-the-goalposts in the best of ways. And if this were a project with a deadline, or one that I weren’t simply enjoying, it would be a problem. Instead, having relatively low-key goals, meeting them, and letting them inspire me to set the next ones has been a blast. It makes me think of Donald Papp’s great article on creating hacking “win” projects. There he suggests creating simple goals to keep yourself inspired. I don’t think I could have planned out an “optimal” set of goals to begin with — I’ve learned too much along the way that the next goal isn’t obvious until I know what new capabilities I have. Creeping is the only way.

What about you? Do you plan your hobby projects completely in advance? Not at all? Or do you have some kind of hybrid, moving-the-goalposts sort of strategy?