Ask Hackaday: Incidental Earthquake Detection

February 9, 2023 by 13 Comments

It never seems to fail: at the very moment that human society seems to reach a new pinnacle of pettiness, selfishness, violence, and self-absorption, Mother Nature comes along and reminds us all who’s really in charge. The obvious case in point here is the massive earthquakes near the border of Turkey and Syria, the appalling loss of life from which is only now becoming evident, and will certainly climb as survivors trapped since the Monday quakes start to succumb to cold and starvation.

Whatever power over nature we think we can wield pales by comparison with the energy released in this quake alone, which was something like 32 petajoules. How much destruction such a release causes depends on many factors, including the type of quake and its depth, plus the soil conditions at the epicenter. But whatever the local effects on the surface, quakes like these have a tendency to set the entire planet ringing like a bell, with seismic waves transmitted across the world that set the needles of professionally maintained seismometers wiggling.

For as valuable as these seismic networks are, though, there’s a looser, ad hoc network of detection instruments that are capable of picking up quakes as large as these from half a planet away. Some are specifically built to detect Earth changes, while some are instruments that only incidentally respond to the shockwaves traveling through the planet. And we want to know if this quake showed up in the data from anyone’s instruments.

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Five Years On, Where Is Starman And Where Will He Go?

February 9, 2023 by 55 Comments

On 6 February 2018, a Tesla Roadster was launched as the mass simulator on the first ever Falcon Heavy launch — putting for the first time ever a car on a Mars-crossing orbit. While undoubtedly a bit of a stunt, the onboard cameras provided an amazing view of our planet Earth as the Starman dummy in the Roadster slowly drifted away from that blue marble, presumably never to be seen again.

This “never” is the point that researchers at the University of Toronto would like to clarify in a paper published after the launch titled The Random Walk of Cars and Their Collision Probabilities with Planets. Using N-body simulations, they come to the conclusion that there’s a 22%, 12%, and 12% chance of the Roadster impacting the Earth, Venus, and the Sun, respectively. But don’t get too excited, it’s not due to happen for a few million years, so it isn’t something any of us will be around to see.

As the Where Is Starman? website shows, the Roadster never reached escape velocity from the Sun’s gravity, meaning that it’s still zipping around in an orbit around our day star. Exposed to the harsh UV and other radiation, it’s likely that very little is left at this point of the Tesla, or Starman himself. Even so, scientists to this day are feeling less than amused by what they see as essentially littering, adding to the discarded rocket stages, dead satellites and other debris that occasionally makes it into the news when it smashes into the Moon, or threatens the ISS.

Utility Mat Turns Waste Epoxy Into Useful Tools

February 9, 2023 by 46 Comments

Epoxy is a great and useful material typically prepared by mixing two components together. But often we find ourselves mixing too much epoxy for the job at hand, and we end up with some waste left behind. [Keith Decent’s] utility mat aims to make good use of what is otherwise waste material.

The concept is simple yet ingenious. It’s a flexible mat that serves as a mold for all kinds of simple little plastic workshop tools. The idea is that when you have some epoxy left over from pouring a finish on a table or laying up some composites, you can then pour the excess into various sections of the utility mat. The epoxy can then be left to harden, producing all manner of useful little tools.

It may seem silly, but it could save your workshop plenty of nickels and dimes. Why keep buying box after box of stir sticks when you can simply make a few with zero effort from the epoxy left from your last job? The utility mat also makes other useful nicknacks like glue spreaders, scrapers, wedges, and painter’s pyramids.

We’ve seen other great recycling hacks over the years too. Video after the break.

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The ARPANET Of Things And CMU’s History Of Networked Soda Machines

February 8, 2023 by 10 Comments

When the computer science department of Carnegie Mellon University expanded in the 1970s, this created a massive issue for certain individuals who now found that they had to walk quite a distance to the one single Coke machine. To their dismay, they’d now find that after braving a few flights of stairs, they’d find that the Coke machine (refilled randomly by grad students) was empty, or worse, had still warm Coke bottles inside. What happened next is detailed by the Coke machine itself, straight from the CMU’s servers.

A follow-up by the IBM Industrious blog adds more feedback from those responsible for we now refer to as an IoT device, though technically it was an AoT at the time, being a pre-Internet era. For the bottle-based, 1970s machine, microswitches were installed by students in the machine to keep track of the fill state of each column and for how long the bottles had been inside. After about 3 hours newly added bottles were registered as being ‘COLD’, which could be queried from the PDP-10’s mainframe (CMUA) or via ARPANET using the finger command on the special ‘coke’ user account with finger coke@cmua.

As time moved on and the coke machine was replaced  in the early 90s with a newer (and very much non-IoT) model, students would once again attempt to modify it, much to the chagrin of the Coke company’s maintenance people, resulting in the students reverting modifications prior to a maintenance appointment. This tracking system used the empty column lights on the machine, leading to a similar tracking system as on the 1970s machine, except now running on a PC-XT class computer that also tracked the status of the M&M snack machine nearby.

Whether CMU CS students can still query such highly relevant information today is not mentioned, but we presume it is an issue of paramount importance that has been addressed in an expedient fashion over the intervening years.

(Thanks to [Daniel T Erickson] for the tip)

Understanding AI Chat Bots With Stanford Online

February 8, 2023 by 8 Comments

The news is full of speculation about chatbots like GPT-3, and even if you don’t care, you are probably the kind of person that people will ask about it. The problem is, the popular press has no idea what’s going on with these things. They aren’t sentient or alive, despite some claims to the contrary. So where do you go to learn what’s really going on? How about Stanford? Professor [Christopher Potts] knows a lot about how these things work and he shares some of it in a recent video you can watch below.

One of the interesting things is that he shows some questions that one chatbot will answer reasonably and another one will not. As a demo or a gimmick, that’s not a problem. But if you are using it as, say, your search engine, getting the wrong answer won’t amuse you. Sure, you can do a conventional search and find wrong things, but it will be embedded in a lot of context that might help you decide it is wrong and, hopefully, some other things that are not wrong. You have to decide.
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Simple Wood-Fired Water Heater Is Surprisingly Effective

February 8, 2023 by 55 Comments

These days, humans have gotten all fancy-schmancy with their gas and electric water heaters. Heck, some are even using heat pumps to do the work as efficiently as possible. [HowToLou] got back to basics instead, with his simple wood-fired water heater design.

The design is straightforward, featuring 100ft of quarter-inch copper tubing wrapped directly around a steel barrel. Room-temperature water is fed into the tubing via a garden hose, and comes out much hotter, thanks to a fire burning away in the barrel stove of [Lou’s] own construction.

For an input water temperature of 41 F, the output reaches 105 F at a flow rate of 0.67 gallons per minute. By [Lou]’s calculations, that’s a heat transfer to the water of roughly 21,000 BTU per hour. [Lou] achieved this with just $55 worth of copper tubing, and he notes that simply doubling up the tubing would increase the heat transfer to the water even further.

If you’re looking for a hot shower from your outdoor wood stove, a build like this might be just the ticket. With the stove burning hot and your hose as a water supply, you could experience the joy of the hot water while you’re standing in the snow outside. We’ve seen [Lou]’s work before, too. Video after the break.

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Building A Plasma Piano Ain’t Easy

February 8, 2023 by 17 Comments

Electronic arcs can be made to “sing” if you simply modulate them on and off at audible frequencies. We’ve seen it done with single Tesla coils, and even small Tesla choirs, but [Mattias Krantz] took this to extremes by building an entire “plasma piano” using this very technique.

The build relies on ten transformers more typically used in cathode ray tubes. The transformers are capable of generating high enough voltages to create arcs in the air. The transformers are controlled by an Arduino, which modulates the arcs at musical frequencies corresponding to the keys pressed on the piano. Sensing the keys of the piano is achieved with a QRS optical sensor strip designed for performance capture from conventional pianos. For the peak aesthetic, the transformer outputs are connected to the metal hammers of the piano, and the arcs ground out on a metal plate in the back of the piano’s body. This lets arcs fly across the piano’s whole width as its played. Ten transformers are used to enable polyphony, so the piano to play multiple tones at once.

Building the piano was no mean feat for [Mattias], who admitted to having very limited experience with electronics before beginning the build. However, he persevered and got it working, while thankfully avoiding injury from high voltage in the process. This wasn’t easy, as Arduinos would regularly freeze from the noise produced by the arcs and the system would lose all control. However, with some smart software tweaks to the arc control and some insulating panels, [Mattias] was able to get the piano playable quite well with a beautiful chiptune tone.

It bears stating that HV work can be dangerous, and you shouldn’t try it at home without the proper understanding of how to do so safely. If you’re confident though, we’ve featured some great projects in this space before. Video after the break.

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