To Give Is Better Than To Receive

September 2, 2023 by Elliot Williams 24 Comments

Better to give a talk at a hacker event, that is. Or in your hackerspace, or even just to a bunch of fellow nerds whenever you can. When you give the talk, don’t be afraid to make it too “easy” to understand. Making a tough topic comprehensible is often the sign that you really understand it, after all, and it’s also a fantastic service to the audience. And also don’t be afraid that your talk isn’t “hard core” enough, because with a diverse enough crowd, there will absolutely be folks for whom it’s still entirely new, and they’ll be thankful.

These were the conclusions I got from talking to a whole range of people at Chaos Communication Camp the weekend before last, and it’s one of the great opportunities when you go to an event like this. At Camp, there were a number of simultaneous stages, and with so many talks that new ones are still being released. That meant that everyone had their chance to say their bit, and many many did.

And that’s great. Because it’s obvious that getting the work done, or diving deep into a particular topic, is part of the hacker experience, but it’s also equally important to share what you’ve gained with the rest of the community. The principle of spreading the knowledge is a cornerstone of our culture, and getting people up to talk about what they’ve learned is the manifestation of this cultural value. If you know something, say something!

Of course, when you’re not at a conference, you could be writing up your hacks and sending them in to the tips line (hint, hint!). That’ll work too.

How Do They Do That?

August 26, 2023 by Elliot Williams 20 Comments

Last week’s Chaos Communication Camp is kinda a big deal: 6,000 hackers all out in a field all need power, food, drink, networking, and of course, sewage in the middle of nowhere. Oh yeah, plus video services on multiple simultaneous stages, custom phone infrastructure, a postal service, and even a diesel train. How is that even possible to run with only volunteers? How do they even know how to run something this scale?

My wife asked me this question while we were driving up to Berlin, and the answer is of course the same as it is to “Excuse me, can you tell me how to get to Carnegie Hall?” Practice.

But it’s not just practice. It’s also passing down the lessons learned to the next generation, making procedures that are not 100% dependent on the people doing the jobs, but can be passed on to the next volunteer willing to pick up the torch.

And then I was interviewing [Jens Ohlig] and [Mitch Altman] about the early days of the second wave hackerspaces in America for the podcast. (Some great interviews – go check it out!) The central story there is essentially the same: the critical missing ingredient that lead to the blossoming of US hackerspaces was simply a set of instructions and design principles – drawing on the experience of established hackerspaces.

Sharing information is a fundamental cornerstone of the hacker ethic, and it gives the next hacker a leg up. Contributes to the global hive mind. And it makes things possible that would otherwise seem impossible. Pushing the hacker state-of-the-art is what Hackaday is all about, and we’re used to thinking of it in terms of a particular microcontroller library, but seeing how the same sharing makes impossible logistics possible was inspirational. Don’t be afraid to start small and iterate – and take good notes.

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!