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Living on Mars: the Stuff You Never Thought About

พฤ, 08/17/2017 - 21:01

In The Martian we saw what kind of hacking was needed to stay alive for a relatively short while on Mars, but what if you were trying to live there permanently? Mars’ hostile environment would affect your house, your transportation, even how you communicate. So here’s a fun thought experiment about how you’d live on Mars as part of a larger community.

Not Your Normal House Mars One living units under regolith, Source video

Radiation on Mars comes from solar particle events (SPE) and galactic cosmic radiation (GCR). Mars One, the organization planning one-way trips to Mars talks about covering their habitats in several meters of regolith, a fancy word for the miscellaneous rocky material covering the bedrock. Five meters provides the same protection as the Earth’s atmosphere — around 1,000 g/cm2 of shielding. A paper from the NASA Langley Research Center says that the largest reduction comes from the top 15 to 20 cm of regolith. And so our Mars house will have an underlying structure but the radiation protection will come from somewhere between 20 cm to a few meters of regolith. Effectively, people will be living underground.

On Earth, producing water and air for your house is not something you think of doing, let alone disposing of exhaled CO2. But Mars houses will need systems for this and more.

Finding Water Water equivalent hydrogen within 60° on Mars

Water is a mix of hydrogen and oxygen and is abundant in the form of ice mixed into the top meter of the Martian regolith. Around the equator and up to 60° latitude it varies in concentration from 2-18% but further north and south it’s in even higher concentrations, reaching 100% at the north pole.

As in Earth cities, water will be piped or carried in from elsewhere, or it can be produced by the house environmental system from deliveries of regolith from the nearest quarry. In any case, it’s produced by heating regolith to turn the ice to vapor and then condensing the vapor to liquid water. Mars One hired Paragon Space Development Corporation, specialists in space environmental systems, to come up with a design for their habitats. Their design includes a hopper for putting regolith into as the first step in producing water.

Trifles Like Air, Toxins, and Food

Mars air is 95% carbon dioxide (CO2), 1.93% argon, 1.89% nitrogen and only 0.16% oxygen. Our Earth atmosphere, however, contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% CO2, and trace amounts of other gases. In The Martian, fresh oxygen for breathing was taken from CO2 in the Mars air. In Paragon’s environmental system, oxygen is also taken from CO2 in the Mars air but also takes nitrogen, argon and trace amounts of CO2 for a more complete mix. In addition, Paragon’s system also takes some oxygen from the water production system using electrolysis.

Interestingly, one of the less obvious issues is keeping toxic elements present in the dust from entering the house. Mars dust is electrically charged and sticks to everything, much like styrofoam packaging. If you’ve lived in environments where you had to clean your boots before entering the house, imagine having to clean your whole space suit, or you could just leave it in the airlock.

Growing food on Mars is possible — we know because we’ve reported on tests done with analogs of Mars soil. Some food will be grown in the house, for the side-benefit that plants absorb CO2 and exhale oxygen. But for variety, quantity and for saving time, much of it will come from separate greenhouses.

Of course, through all this we must keep in mind that all waste, used water, and exhaled air is recycled and reused in an effort to get as closed-loop as possible. That means the requirements for raw inputs would be less than they would be on Earth.

Electrical Ground On Mars

Mars doesn’t have a local electrical ground. The Earth does because the ground is electrically conductive and accepts charge from any charged object that comes in contact with it. Due to the large mass of a local Earth ground, it accepts this charge without becoming very charged itself. The moisture in the Earth ground aids its conductivity by enabling ions to move around. Mars’ ground, however, is dry and while it contains ice, that ice further decreases conductivity.

Mars is also dusty. That dust blowing around can charge space suits, vehicles, and parts of houses not covered in regolith. This is due to the triboelectric effect and is the same thing that happens when you walk across a carpet (charging your body) and then get a shock when you touch a doorknob. In the case of Mars, it’s the interaction between the dust and other objects that does the charging.

Since there’s no local electrical ground to discharge objects, they can build up different charge amounts. After walking around outside, when a person arrives at an airlock and presses a button to open it, a spark can pass between them, damaging sensitive electronics.

The solution is to design systems keeping in mind that there is no natural local ground. To get a local ground, while not a complete solution, electrically connecting houses and other structures via cables results in a giant capacitor, storing charge. Sharp metal points and normal building irregularities would help to discharge that built-up charge back to the atmosphere like a reverse lightning rod.

Wireless Communication Issues Mars houses with antennas

As pointed out above, the housing is basically underground. This causes a problem when trying to transmit high frequency signals wirelessly. Of course one solution is to use cables, either copper or fiber optic. But if we want to keep things simple and flexible then the houses would simply have antennae extending outside the regolith roofs.

If houses are truly underground then cues can be taken from the mining industry’s through-the-earth mining communication systems. This transmits signals at ultra-low frequencies of 300-3000 Hz and can transmit through hundreds of meters of rock. The transmitter uses a large loop antenna on, or just under, the surface that transmits through the ground to the dwellings below.

Cavers have also done this for distances of a few hundred meters with more portable units with multiple turns for the loops. This is not normal broadcasting of electromagnetic waves but rather magnetic induction through rock, the transmitter’s loop creating a magnetic field which induces a matching one in the receiver’s loop.

But given the low bandwidth available with such low frequencies, we’ll either use exterior antennas, or cables for most communication.

Appliances Chris Hadfield with water bubble in the ISS, Source NASA

The biggest impact on appliances used within the habitat compared to on Earth is Mars’ gravity, three-eighths that of Earth’s. We’ve certainly plenty of demonstrations of micro-gravity from the ISS. Mostly this would affect things that deal with fluids. For example, the blades in a food blender are at the bottom but would that work as well if the downward pull is half as strong?

In our article about Earth grounding for houses on the electrical grid, we showed various places that the ground played a part in our electrical system.

Appliances with metal cases often have an equipment grounding wire connecting that metal case to Earth ground. This is to discharge any charge built up on the appliance’s case due to things like nearby lightning strikes. But while lightning does occur on Mars in dust storms, it isn’t the form that would send charge through the ground and into appliances. Instead it’s more in the form of a glow within the dust clouds and doesn’t involve the ground.

That’s not to say that those appliances won’t need a ground prong on their plugs. The part of the circuit that trips the breaker if the live wire shorts to the metal case, doesn’t involve ground and is still required. Again, see our grounding article if you’re puzzled why that is.

And remember the days when people used to repair broken appliances rather than just buy new ones? That’ll be the norm on Mars, as will making your own things. Hackers will do well on Mars.

Generating Electricity Opportunity rover’s wind cleaned solar panels, Source: NASA

Solar panels have been used by most of NASA’s Mars rovers and have kept them powered for long periods of time. As such, solar panels can be used for power for our houses. Dust can cover these solar panels, but unlike with the rovers, people will be present to clean them. Dust storms can be an issue though. The Spirit and Opportunity rovers landed in 2004 and encountered only one big dust storm in 2007. That had them going into survival mode for a few weeks. So just as with off-grid systems on Earth, a backup power system is needed.

Geothermal energy (areothermal energy on Mars) is one possible source but it’s unknown how deep you’d have to drill, 1 kilometer or 10 kilometers, before reaching hot enough temperatures. The deeper you drill, the more energy you need to do it. It will also require a large amount of steel piping, which can be made from the iron oxide which makes up the bulk of Mars regolith. Compressed and liquified CO2 can be used as the heat transfer fluid.

Nuclear power is also an option, using radioisotope thermoelectric generators (RTG) for example. However, replacement radioactive materials will be needed in the long-term. If necessary, this can be a product bought from Earth suppliers.

Going Outside

Venturing outside on Mars is problematic. The surface air pressure is only 0.00628 atm, with Earth at sea level being 1 atm, or 1 standard atmosphere.

Flight engineer Petit helping MS Herrington don his EMU space suit, Source: NASA

People would have to wear space suits, and we’ve already talked about how the suits would collect dust and bring it indoors. It also takes a lot of time to suit-up and unsuit. In the movie Gravity, Sandra Bullock unsuited in under a minute but that rapid speed was to keep the plot going. In reality it takes astronauts on the ISS a lot longer as they first have to don a skin-tight undergarment threaded with tubes for thermal control, followed by bending into the semi-rigid parts that make up the suit proper. All this time, everything is being checked. The process could be sped up of course, but there’s still more involved than tying your shoes and throwing on a jacket.

So how about instead slipping into a vehicle parked in a garage-sized airlock, depressurizing the garage, and driving out? There are a few problems here. One is the time required to cycle such a large volume. Another is the loss of air in cycling such a large airlock. Yet another is the huge opening required that invites abundant dust. It’s probably just as fast to suit-up and slip into an open vehicle waiting outside. Since it’s always outside, you wouldn’t need to clean the dust off it every trip.

Another option is to have tunnels between houses. That’s a large volume to keep filled with breathable air and kept warm so you’d probably want to do it on a small scale.

To avoid the above mentioned issues, for many jobs you could send a robot instead, one that remains outside and needs only periodic maintenance. Robots could keep the solar panels clean, carry supplies from place to place, and do routine maintenance. They could have some level of autonomy but still be teleoperated as needed.

Home Sweet Home

And so that’s our thought experiment about living on Mars. Does it make you want to pull up stakes and move? What would you do differently? What issues have we missed? Let us know in the comments below.

Filed under: Engineering, Featured, Original Art

Multiple Monitors With Multiple Pis

พฤ, 08/17/2017 - 18:00

One of the most popular uses for the Raspberry Pi in a commercial setting is video walls, digital signage, and media players. Chances are, you’ve probably seen a display or other glowing rectangle displaying an advertisement or tweets, powered by a Raspberry Pi. [Florian] has been working on a project called info-beamer for just this use case, and now he has something spectacular. He can display a video on multiple monitors using multiple Pis, and the configuration is as simple as taking a picture with your phone.

[Florian] created the info-beamer package for the Pi for video playback (including multiple videos at the same time), displaying public transit information, a twitter wall, or a conference information system. A while back, [Florian] was showing off his work on reddit when he got a suggestion for auto-configuration of multiple screens. A few days later, everything worked.

Right now, the process of configuring screens involves displaying fiducials on each display, taking a picture from with your phone and the web interface, and letting the server do a little number crunching. Less than a minute after [Florian] took a picture of all the screens, a movie was playing across three weirdly oriented displays.

Below, you can check out the video of [Florian] configuring three Pis and displays to show a single video, followed by a German language presentation going over the highlights of info-beamer.

Filed under: Raspberry Pi

Krave Antweight Robot Gets Eaten And Stays Alive

พฤ, 08/17/2017 - 15:00

The battle’s are done and the results are in — [AltaPowderDog]’s, aka [Carter Hurd],  cardboard and foam armor, lightweight Krave robot beat its metal cousins in 2016 and fared well in 2017. How did a cardboard Krave cereal box and foam board robot do that you ask? The cardboard and foam outer structure was sliced, smashed and generally eaten while the delicate electronics, motors and wheels remained buried safely inside.

We covered the making of his 2016 version but didn’t follow-up with how it fared in that year’s Illinois Bot Brawl competition. As you can see in the exciting first video below, despite suffering repeated severe damage to its armor, it won first place in the 1 lb Antweight category!

For 2017 he made another one but managed to halve the weight — and so he made two of them! By starting them both within a twelve-inch by twelve-inch area, they were allowed to fight as a team. How did he make it lighter? Partly it was done by doing away with the ability to lift the metal lip in front, the wheels were reduced from four to two, and a smaller servo was used for opening and closing the mouth. The full build video is shown below along with a video of the 2017 battles wherein he won seventh place.

The 2016 victorious battles…

Making the 2017 robot…

The battles of 2017…

The Krave cereal box robot isn’t the only food-related bot we’ve covered here. Check out the butter passing battlebot and this battlebot made out of a pumpkin.

Filed under: robots hacks

Wield The Power of Molten Metal

พฤ, 08/17/2017 - 12:00

[TheBackyardScientist] at it again with another super villain-esque demonstration of gadgetry: a liquid metal squirt gun.

The squirt gun has a compressed air tank like most others — more on that later — but to fire its primary ammunition, a nozzle that connects directly to an air compressor is needed. Again, like most guns of this nature, air is forced into the gun’s reservoir, displacing the pewter and expelling it out the gun’s barrel. Yes, pewter.

Working around the heat tolerances of thread seal tape, pewter has a low enough melting point that an airtight system is preserved — plus it’s really cool to fire a stream of liquid metal. The ammunition is made from pewter ware melted down and cast into pucks. These pucks are stacked into the gun’s magazine, melted with a propane torch and carefully loaded into the gun.

The built-in compressed air tank lacks the oomph to push out the pewter — hence the air compressor, but any lighter liquids or condiments are fair game for rapid-fire exercises. Yes, condiments.

Due to the low melting point of pewter, a humble pane of glass — or even, yes, a watermelon — can effectively stand up to the onslaught, but you probably don’t want to unleash this during the next water fight.

The last time we featured [TheBackyardScientist]’s shenanigans involving pewter he was casting it into weapons. If you have access to a 3D printer, you can cast yourself some pretty intricate designs.

[Thanks for the awesome tip, Itay!]

Filed under: misc hacks, weapons hacks

A Great Way to Make Quick and Easy Knobs

พฤ, 08/17/2017 - 09:00

Here’s a great way to quickly and easily make attractive and functional knobs with no tools required. All you need is some casting resin (epoxy would do in a pinch), a silicone mold intended for candy, and some socket head bolts. With the right preparation and a bit of careful placement and attention, smooth and functional knob ends are only minutes away. Embedded below is a short video demonstrating the process.

These may not replace purpose-made knobs for final products, but for prototypes or to use around the shop on jigs, clamps, or furniture they certainly fit the bill. With a layer of adhesive fabric or rubber, they might even make serviceable adjustable feet for low-stress loads.

This technique could be extended to reproducing broken or missing dakaware or bakelite knobs. This, of course, would require an original, unbroken knob and a small silicone mold, but it’s still a project that’s well within the capabilities of the garage-bound hacker.

While we’re on the subject of knobs, don’t forget we’ve seen an excellent method of repairing knobs as well.

Filed under: how-to, tool hacks

Bringing A 50 Watt Laser Cutter to Life

พฤ, 08/17/2017 - 06:01

This is the future and we live in a world of 3D printers and laser cutters. Have you ever pondered the question of getting yourself a laser cutter? Well [Erich Styger] just landed a 50 Watt Laser Cutter from AliExpress and has written up a detailed guide to his experience.

[Erich] had been wrestling with the idea of buying one for himself for some time but was put off by the difficulty in their operation. This changed when [Scorch] published the K40 Whisperer control software which allows for better control over these machines. With the hopes of an interesting weekend project, [Erich Styger] took a leap of faith and spent $900 on a model 4040 laser cutter.

In his blog, he goes through the steps in setting up the machine as well as calibrating the laser. With a plethora of images and a detailed look at each aspect of the leveling and testing, [Erich Styger] had a weekend well spent and a working K40 laser cutter for his workshop. But perhaps the more valuable part of the stories is the overall experience.

It was not a “what you see is what you get” order, but it did turn out to be a hacker’s “what you want is what you get” adventure. The machine didn’t look the same as the picture, it came with a burned CD-R with a box full of small parts (in addition to separate shipment of a USB thumb drive and silicone sealant), and there were some mechanical touchups plus a stuck switch requiring reassembly. He has done an excellent job of documenting from order to test-runs and the photos alone are worth taking a look.

Adding value to inexpensive laser cutters in an often-featured project around here. If you are looking for more details on these wonderful machines, be sure to check out more tales of Cheap Laser Cutters and our coverage of the K40 Whisperer software launch from last month.

Filed under: laser hacks, tool hacks

Superconference Interview: Ben Krasnow

พฤ, 08/17/2017 - 03:00

Ben Krasnow is a consummate prototyper. He’s built a machine that makes the perfect chocolate chip cookie, he has a ruby laser, and he produces his own liquid nitrogen in-house because simply filling up a dewar is too easy. If you need a prototype, Ben is the guy to talk to.

Ben gave a talk at last year’s Hackaday Superconference on prototyping quickly and verifying technical hypotheses. The philosophy can be summed up simply as, ‘Build First, and Ask Questions Later’. This philosophy served him well when he wanted to see if backscatter x-ray machines were actually more effective than metal detectors at TSA checkpoints. The usual bean-counter protocol for answering this question would be to find an x-ray expert, wait weeks, pay tens of thousands of dollars, and eventually get an answer. Ben simply built his own backscatter x-ray machine from parts sourced on eBay.

After the talk, we asked Ben about the limits of this philosophy of building first and asking questions later. With the physical and mental toolset Ben has, it’s actually easy to build something that can get in the ballpark of answering a question. The problem comes when Ben needs to prove something won’t work.

Answering this question is all a matter of mindset. In Ben’s view, if a prototype works, a hypothesis is verified. Even if it’s a complete accident, he’s totally okay with the results. Some of his other colleagues have an opposite mindset — if a quick and dirty prototype doesn’t work, a research hypothesis is verified.

This rapid-proof-of-concept mindset is something we see a lot in the Hackaday audience, and we know there are some of you out there who have a mind and garage that is at least as impressive as Ben’s. We’ve extended the Call for Proposals for the 2017 Hackaday Superconference. If you have a story about rapid prototyping or just making the perfect chocolate chip cookie with robots, we want to hear about it. Tickets are still available for the Superconference in Pasadena, California on November 11th and 12th.

Filed under: cons, Interviews

Fridge Compressor to 2-Stroke Engine: JB Weld for the Win

พฤ, 08/17/2017 - 01:30

We like this one because it has a real Junkyard Wars feel to it: turning a cast-off fridge compressor into a two-stroke internal combustion engine. [Makerj101] is doing this with tooling no more complicated than a hacksaw and a hand drill. And JB Weld — lots and lots of JB Weld.

[Makerj101]’s video series takes us through his entire conversion process. Despite the outward similarity between compressors and engines, there are enough crucial differences to make the conversion challenging. A scheme for controlling intake and exhaust had to be implemented, the crankcase needed to be sealed, and a cylinder head with a spark plug needed to be fabricated. All of these steps would have been trivial in a machine shop with mill and lathe, but [Makerj101] chose the hard way. An old CPU heat sink serves as a cylinder head, copper wire forms a head gasket and spacer to decrease the compression ratio, and the old motor rotor serves as a flywheel. JB Weld is slathered everywhere, and to good effect as the test run in the video below shows.

Think you recognize [Makerj101]? You probably do, since we featured his previous machine shop-less engine build. This guy sure gets his money’s worth out of a tube of JB Weld.

Thanks to [Gregg Eshelman] for the tip.

Filed under: hardware, misc hacks

The Best Stereo Valve Amp In The World

พฤ, 08/17/2017 - 00:01

There are few greater follies in the world of electronics than that of an electronic engineering student who has just discovered the world of hi-fi audio. I was once that electronic engineering student and here follows a tale of one of my follies. One that incidentally taught me a lot about my craft, and I am thankful to say at least did not cost me much money.

Construction more suited to 1962 than 1992.

It must have been some time in the winter of 1991/92, and being immersed in student radio and sound-and-light I was party to an intense hi-fi arms race among the similarly afflicted. Some of my friends had rich parents or jobs on the side and could thus afford shiny amplifiers and the like, but I had neither of those and an elderly Mini to support. My only option therefore was to get creative and build my own. And since the ultimate object of audio desire a quarter century ago was a valve (tube) amp, that was what I decided to tackle.

Nowadays, building a valve amp is a surprisingly straightforward process, as there are many online suppliers who will sell you a kit of parts from the other side of the world. Transformer manufacturers produce readily available products for your HT supply and your audio output matching, so to a certain extent your choice of amp is simply a case of picking your preferred circuit and assembling it. Back then however the world of electronics had extricated itself from the world of valves a couple of decades earlier, so getting your hands on the components was something of a challenge. I cut out the power supply by using a scrap Dymar Electronics instrument enclosure which had built-in HT and heater rails ready to go, but the choice of transformers and high-voltage capacitors was something of a challenge.

Pulling the amplifier out of storage in 2017, I’m going in blind. I remember roughly what I did, but the details have been obscured by decades of other concerns. So in an odd meeting with my barely-adult self, it’s time to take a look at what I made. Where did I get it right, and just how badly did I get it wrong?

Lovingly hand-drawn from life, missing the PSU components.

The amp itself sits in the removable portion of the Dymar chassis, I can’t remember what the dead instrument was, but Dymar produced a range of instruments as modules for a backplane. The front panel is a piece of sheet steel I cut myself, and is still painted in British Leyland Champagne Beige, the colour of that elderly Mini. It has a volume control, a DIN input socket which must have seemed cool to only me in 1992, and a Post Office Telephones terminal block for the speakers. Inside the chassis the amp is mounted on a piece of aluminium sheet, on top a pair of PCL86 triode/pentode valves, a pair of output transformers and a supply smoothing capacitor, and underneath all the smaller components on tag strips. Though I say it myself, it’s a tidier job than I remember.

1969’s hot new device, already obsolete by 1980.

The circuit is simple enough, a single-ended Class A audio amplifier that I lifted along with the PCL86 and the original output transformers, from a commonly available (at the time) scrap ITT TV set. These triode/pentodes were the integrated amplifier device of their day, as ubiquitous as an LM386 in later decades, containing a triode as preamplifier and a power output pentode, and capable of delivering a few watts of audio at reasonable quality with very few external components. They were also dirt cheap, the “P” signifying a 300mA series heater chain as used in TV sets that was considerably less desirable than the “E” versions which had the standard 6.3V heaters. Not a problem for me, as the Dymar PSU had a 12V rail that could happily give almost the 300mA each to a couple of PCL86s.

My choice of parts must have been limited to those my university’s RS trade counter had in stock that had the required working voltage, and are a mixed bag that you wouldn’t remotely class as audio grade. There are a couple of enormous 450V 33μF electrolytics, and 250VAC Class Y 0.1μF polymer capacitors intended for use in power supply filters. I seem to have followed the idea of using a small and a large capacitor in parallel, probably for some youthful hi-fi mumbo-jumbo idea about frequency response. Otherwise the resistors look like carbon film components, something that probably made more sense to me in the early 1990s than it does now.

On top of the chassis, the original transformers taken from scrap TV sets turned out to be of such low quality that they tended to “sing” at any kind of volume, so I shelled out on a pair of the only valve audio output transformers I could find at the time, something that must have been a relic of a bygone era in the RS catalogue. The original valves were a pair of PCL86s from old TVs, but I replaced them with a “matched” pair of brand new PCL86s. I remember these cost me 50p (about 90¢ in ’92) each at a radio rally, and were made in Yugoslavia with a date code of January 1980. The new valves didn’t make any difference, but they made me feel better.

How did this amplifier perform, and what did I learn from it? Under the hood, and it’s all a bit messy.

In the first instance, it performed 110%, because I had a valve amp and nobody else did. The air of mystique surrounding this rarest of audio devices neatly sidestepped the fact that it wasn’t the best of valve amps, but that didn’t matter. Being a class A amplifier with new components, it came to the party with the lowest theoretical distortion it could have had due to its circuit topology. Another area of shameless bragging rights for my younger self, but in reality all it meant was that it got hot.

The sound at first power-on was crisp and sibilant, but with an obvious frequency response problem, it was bass-to-mid heavy, and not in a good way. Here was my first learning opportunity, I had just received an object lesson in real audio transformers not behaving like theoretical audio transformers. It had an impressive impulse response though, square waves came through it beautifully square on my battered old ‘scope.

I could only go so far listening to a hi-fi that might have been a little fi but certainly wasn’t hi. My attention turned to that frequency response problem, and since we’d just been through the series of lectures that dealt with negative feedback I considered myself an expert in such matters who could fix it with ease. I cured the frequency response hump with a feedback resistor from output to input, playing around with values until I lit upon 330K as about right.

The Best Stereo Valve Amp In The World. Yeah, right.

Here was my second learning experience. I’d made a pretty reasonable amplifier as it happens, and it sounded rather good through my junk-shop Wharfedale Linton speakers with cheap Maplin bass drivers. I could indulge my then-held taste in tedious rock music, and pretend that I’d reached a state of hi-fi Higher Being. But of course, I hadn’t. I’d got my flat frequency response, but I’d shot my phase response to hell, and thus my impulse response had all the timing of a British Rail local stopping service. The ‘scope showed square waves would eventually get there, but oh boy did they take their time. The sound had an indefinable wooliness to it, it was clear as a bell but the sibilance had gone. I came away knowing more about the complex and unexpected effects of audio circuitry than I ever expected to, and with an amp that still had some bragging  rights, but not as the audio genius I had hoped I might be.

The amplifier saw me through my days as a student, and into my first couple of years in the wider world. Eventually the capacitor failed in the Dymar PSU, and I bought a Cambridge Audio amp that has served me ever since. The valve amp has sat forlornly on the shelf, a reminder of a past glory that maybe one day I’ll resuscitate. Perhaps I’ll give it a DSP board programmed to cure its faults. Fortunately I have other projects from my student days that have better stood the test of time.

So. There’s my youthful folly, and what I learned from it. How about you, are there any projects from your past that seemed a much better idea at the time than they do now?

Filed under: classic hacks, digital audio hacks, Hackaday Columns, Interest, Original Art

Friday Hack Chat: Graphical Programming Languages with Boian Mitov

พุธ, 08/16/2017 - 23:01

There is a long history of Visual or Graphical Programming Languages, and most of them make more sense than the name of Microsoft’s Visual Basic, C#, and Visual Studio IDE. Some people don’t like to code, and for them, graphical programming languages replace semicolons and brackets with easy-to-understand boxes and wires.

This Friday, we’re going to be talking about graphical programming languages with [Boian Mitov]. He’s a software developer, founder of Mitov Software, and the creator of Visuino, a graphical programming language for the embedded domain. Everything from the Arduino to Teensy, ESP8266, ESP32, the chipKIT, and Maple Mini are supported with this IDE. It’s a simple drag-and-drop way of programming microcontrollers that Scratches an itch (see what I did there?) for an easy way to introduce non-programmers to the embedded world and also provides a faster way to build custom applications.

When it comes to graphical programming languages, we can’t find a better Hack Chat guest than [Boian]. He’s the author of the OpenWire dataflow processing technology — another graphical programming language –, the IGDI+ library, VideoLab, SignalLab, AudioLab, PlotLab, InstrumentLab, and author of VCL for Visual C++. He’s a regular contributor to Blaise Pascal Magazine, too.

During this Hack Chat, we’ll be discussing what makes Visual Programming worth it, how and why it works, when it doesn’t and how to develop a graphical programming language. Visuino will be of special interest, And I’m sure someone will work in a, ‘what’s happening with Max/MSP under Ableton’ question. If you have a question for [Boian], here’s a question sheet to guide the discussion.

Here’s How To Take Part:

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This Hack Chat will take place at noon Pacific time on Friday, August 11th. Here’s a time and date converter!

Log into Hackaday.io, visit that page, and look for the ‘Join this Project’ Button. Once you’re part of the project, the button will change to ‘Team Messaging’, which takes you directly to the Hack Chat.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talk

Filed under: Hackaday Columns

Making a Coil Gun Without Giant Caps

พุธ, 08/16/2017 - 22:00

Whenever we see a coil gun project on the Internet, it seems to involve a bank of huge capacitors. [miroslavus] took a different approach with his gun–he wanted his project to be built without those monster caps.

It’s powered by quadcopter LiPo batteries, 2x 1400 MaH drone batteries wired up in series and triggering 21SWG copper coils that [miroslavus] created with the help of a custom 3D-printed winding rig he designed. The rigs have ridges to help you lay the coils down neatly, and they also have mounts for photodiodes, ensuring the gun knows when it’s loaded.

When triggered, the Arduino Nano activates a pair of IRF3205 MOSFETS with logic signals stepped up to 20V, shooting lengths of 7mm or 8mm steel rod. The gun isn’t exactly creating plasma discharges with its launches, but it’s a fascinating project nonetheless.

Check out the disposable camera coil gun project and the coil guns for newbies posts we previously ran.


Filed under: misc hacks

Eclipse 2017: Was Einstein Right?

พุธ, 08/16/2017 - 21:01

While most people who make the trek to the path of totality for the Great American Eclipse next week will fix their gazes skyward as the heavenly spectacle unfolds, we suspect many will attempt to post a duck-face selfie with the eclipsed sun in the background. But at least one man will be feverishly tending to an experiment.

On a lonely hilltop in Wyoming, Dr. Don Bruns will be attempting to replicate a famous experiment. If he succeeds, not only will he have pulled off something that’s only been done twice before, he’ll provide yet more evidence that Einstein was right.

Eddington’s Expedition

Back in 1915, Albert Einstein first presented a set of field equations he had been working on for eight years. After publishing his Special Theory of Relativity, he searched for ways to work gravitation into his new framework, and finally hit upon a set of nonlinear and fiendishly difficult equations that describe how space and time must curve under the influence of matter and radiation.

Arthur Eddington. Source:
Wikimedia Commons

The physics community took a keen interest in Einstein’s General Theory of Relativity and began looking for ways to prove it. One of the predictions of the theory is gravitational lensing, or the deflection of light by massive bodies (lensing is also a prediction of Newtonian physics, but Einstein’s field equations predict about twice the deflection of light as the classical model). Measuring this effect, though, is no mean feat, mainly because the one thing massive enough and close enough to quantifiably bend light also happens to be really bright itself — the Sun.

What was needed was a total solar eclipse, and conveniently enough, one would occur in May of 1919. With only four years to go, and with the world torn by war, Sir Arthur Stanley Eddington planned a scientific expedition to the island of Principe off the west coast of Africa. He took a series of photographs of stars in the Hyades cluster, and through careful measurement found that Einstein’s predictions were correct. The publication of his results the next year made a huge splash in the popular press, instantly catapulting Einstein into the public eye and kicking off the age of Relativity.

Easier Said Than Done

Curiously, although many other experiments were later conducted to further bolster General Relativity, the Eddington eclipse experiment wasn’t repeated until over half a century later. It’s easy to understand why, though. First, total solar eclipses aren’t exactly common phenomena, and ones that make landfall in accessible locations with at least the hope of good viewing conditions are rare indeed. And until recently, the equipment needed to capture high-quality images with enough precision to measure the vanishingly small gravitational influence of our modest little star was bulky, finicky, and heavy. The sole repeat of the Eddington experiment was a 1973 expedition, again to Africa, that used 6 tons of equipment to generate a single usable image on a 12″ glass plate. The data from the image was good enough to confirm the Eddington results, though.

Advances in optics have made replication of the original experiment a more approachable endeavor lately, but there’s not much call for optical verification of a theory that’s been repeatedly verified by other methods over the last century. In fact, for confirmation of both General and Special Relativity, you need look no further than your smartphone, which uses both equations to correct the time signals from the cloud of GPS satellites orbiting overhead. That’s millions of verifications of the theory, every second of every day.

Why Bother? Don Brun’s eclipse rig: refractor telescope, CCD camera, heavy mount, and tripod. Concrete pad not included. Source: Sky and Telescope

So why is Don Bruns bothering? Why will he be on that Wyoming mountain, praying for clear skies and low winds? Why has he rounded up the best amateur astronomy gear he can find, made multiple dry runs, scouted locations, and even gotten permission to pour a concrete pad to ensure his telescope won’t move during the two minutes of totality? Why has he gone to the extremes he has?

Don’s short answer is that he’s doing it for the challenge. When he first started mulling over the project, it seemed like the advances in optics, CCDs, and computers since 1973, not to mention since 1919, would make replication a breeze. As it turns out, 2017 will not be astronomical cake walk for Don. There are very few bright stars close enough to the sun to provide good points of reference, and the data on their non-deflected coordinates tends to be of poor precision. He needs to measure deflections on the order of 0.01 arcsecond. To put that into perspective, that would be like measuring the length of a pencil in Paris while observing it from New York.

Add to these challenges that Don has just over two minutes of totality, which is pretty short for a total eclipse, and an errant cloud, a gust of wind on his high Wyoming peak, or a forgotten detail could ruin years of effort. No matter what your background, as hackers we can all see that Don has set himself a lofty goal, and we can all relate to the stress he’ll be feeling as the Moon’s shadow comes racing toward his instrumented perch on August 21. As I’m watching totality end from my vantage point in Idaho, I’ll be thinking of Don and hoping that the stress turns into the elation that comes when everything works and your data gives you a glimpse of the workings of nature.

Filed under: Featured, History, Interest, Original Art

Alexa In A Bunny Rabbit

พุธ, 08/16/2017 - 18:00

The Raspberry Pi is the perfect candidate for Google’s AIY where you can talk to a cardboard box with some electronics in it. [BuddyCasino] took on the challenge of squeezing an Alexa Client in an ESP32 and to make things interesting, a bunny rabbit was chosen as the host of the virtual assistant.

A few months ago, we did a teardown of the Google AIY Kit where [BuddyCasino] commented that he managed to port the Echo Dot client into and ESP32. Sure enough, the video below shows a demonstration of the build in action. The project uses the MAX98357A which is the same I2S DAC used in the Google AIY Voice Hat. For the microphone, the device is again an I2S component however unlike the Google AIY kit which uses the SPH0645LM4H, [BuddyCasino] opted for the ICS-43434.

Two NeoPixels are employed as visual indicators for various purposes. This project is an excellent example of how simple and cheap modern-day designs have become. We are hoping to see the author add more features to the design and who knows maybe we will see a Google Assistant port on the ESP32 in the future. Check out the original teardown for more inspiration.

Filed under: misc hacks

You Probably Don’t Want To Find This Toilet In Your Washroom

พุธ, 08/16/2017 - 15:00

Ok, this one is a bit bizarre, but in perfect keeping with the subject matter: a talking toilet ripped from the pages of the Captain Underpants children’s books. Hackaday.io user [hamblin.joe]’s county fair has a toilet decorating contest and at the suggestion of their neighbour’s son, [hamblin.joe] hatched a plan to automate the toilet using an Arduino in the fashion of the hero’s foes.

Two Arduinos make up this toilet’s brains, an Adafruit Wave Shield imbues it with sound capabilities, and a sonic wave sensor will trigger the toilet’s performance routine when someone approaches. A windshield wiper motor actuates the toilet bowl lid via a piece of flat iron bar connected to a punched angle bracket. Installing the motor’s mount was a little tricky, since it had to be precisely cut so it wouldn’t shift while in the toilet bowl. A similar setup opens the toilet tank’s lid, but to get it working properly was slightly more involved. Once that was taken care of there was enough room left over for a pair of 12V batteries and a speaker. Oh, and a pair of spooky eyes and some vicious looking teeth.

If you have a limited number of bathrooms at home or at work, some signage would be useful to know when it’s free and how dangerous it is to enter.

Filed under: Arduino Hacks, Uncategorized

GuitarBot Brings Together Art and Engineering

พุธ, 08/16/2017 - 12:00

Not only does the GuitarBot project show off some great design, but the care given to the documentation and directions is wonderful to see. The GuitarBot is an initiative by three University of Delaware professors, [Dustyn Roberts], [Troy Richards], and [Ashley Pigford] to introduce their students to ‘Artgineering’, a beautiful portmanteau of ‘art’ and ‘engineering’.

The GuitarBot It is designed and documented in a way that the three major elements are compartmentalized: the strummer, the brains, and the chord mechanism are all independent modules wrapped up in a single device. Anyone is, of course, free to build the whole thing, but a lot of work has been done to ease the collaboration of smaller, team-based groups that can work on and bring together individual elements.

Some aspects of the GuitarBot are still works in progress, such as the solenoid-activated chord assembly. But everything else is ready to go with Bills of Materials and build directions. An early video of a strumming test proof of concept used on a ukelele is embedded below.

GuitarBot would fit right in to a band where only the instruments operate unplugged. Speaking of robot bands, don’t forget the LEGO-enabled Toa Mata, or the fully robotic group Compressorhead.

Filed under: musical hacks, robots hacks

The Latest Hacker Camp Badge Comes From BornHack

พุธ, 08/16/2017 - 09:01

If you’re a fan of outdoor hacker camps, or if you’re a SHACamp attendee who’s still coming down from the event high, you may already know about the upcoming BornHack 2017 hacker camp on the Danish island of Bornholm, from the 22nd to the 29th of this month. It’s a smaller camp than many of the others on the calendar, but it makes up for that with a quite reasonable ticket price, a much longer duration, and a location that is a destination in itself.

Today we have news of the BornHack badge announcement, and though the details are a little sketchy it’s safe to say that there should be plenty there to keep attendees occupied. The irregularly-shaped PCB contains a Silicon Labs “Happy Gecko” EFM32 ARM Cortex M0 microcontroller, a 128×64 pixel OLED display, and the usual array of I/O lines. There is no information about its connectivity as it seems the BornHack folks prefer to run a teaser campaign, but we’d be surprised if there wasn’t some kind of wireless module on the reverse.

Barring a transportation miracle it’s unlikely that any of the Hackaday team will be making it to BornHack, but that’s our loss. It may not be one of the larger camps, but it looks to offer no less of the atmosphere you’d expect from a European hacker camp. At the time of writing there are still BornHack tickets to be had, so head on over to their website if you fancy a week at a hacker camp on a Danish island.

Filed under: cons

A Gas Model Made of Magnets

พุธ, 08/16/2017 - 07:31

Magnets are great stuff and everyone loves them, there are so many things you can do with them, including creating a model of the crystalline structure of solids, just as [Cody´s Lab] did using a bunch of magnets inside a pair of plexiglass sheets.

Crystal structure of ice. Image from Wikemedia Commons.

Many materials have their atoms arranged in a highly ordered microscopic structure — a crystal — including most metals, rocks, ceramics and ice, among others. The structure emerges when the material solidifies looking for the minimum energy configuration. Every atom interacts with its neighbors via microscopic forces forming several patterns depending on the specific material and conditions.

In his macroscopic world, [Cody´s Lab] used the magnets as his “atoms” and the magnetic repulsion between them represent the microscopic forces. Confining the magnets inside two transparent walls, one can see the formation of the crystal structure as magnets are added one by one.

This is an excellent teaching resource and also a fun way to play with magnets if you want to give it a try. Or if you want another magnet hack, we have tons of them, including implanting them in your body, or making your own with 3D printing.

Filed under: misc hacks

Use a Drill to Power Your Flipbooks

พุธ, 08/16/2017 - 06:00

[WolfCat] of Wolfcatworkshop is creating a hand-animated split-flap animation. But what do you use to test your animation once it’s on the split-flaps? Well, to test it out, [WolfCat] used a drill to give it motion. DoodlersAnonymous has some pics and an interview with [WolfCat] about his animation and there are some pictures on his Instagram page.

Technically, what [WolfCat] wanted to make is a “mutoscope,” a hand-cranked precursor to the movie projector that had its heyday in the late 19th and early 20th century. Originally installed in penny arcades and the like, mutoscopes were single-viewer apparatus. The viewer cranks the handle and the animated cards inside rotate around, stopped briefly by a bit of metal at the top in order to show a frame. The basic idea is similar to the way split-flap clocks or signs work.

[WolfCat] hand drew the animation for his movie and then scanned and printed out each frame. The frames were then transferred to a pair of flaps. [WolfCat] wanted to see how it would look when animated, but didn’t have any plans at the time for a case or a hand crank, so he found the closest tool that would do the job – a cordless drill. Attaching the drill and using a bit of card or wood as a stopper, [WolfCat] could see how the end result would look and could then start work on the case and crank.

The drill is a quick and easy way to see what the finished product would look like. Once he’s got it working, [WolfCat] could check out this 3D printed mutoscope case, or this flip dot animated display.

Filed under: hardware

Hackaday Prize Entry: A Bracelet for the Blind

พุธ, 08/16/2017 - 03:00

The World Health Organization estimates that around 90% of the 285 million or so visually impaired people worldwide live in low-income situations with little or no access to assistive technology. For his Hackaday Prize entry, [Tiendo] has created a simple and easily reproducible way-finding device for people with reduced vision: a bracelet that detects nearby objects and alerts the wearer to them.

It does its job using an ultrasonic distance sensor and an Arduino Pro Mini. The bracelet has two feedback modes: audio and haptic. In audio mode, the bracelet will begin to beep when an object is within 2.5 meters. And it behaves the way you’d expect—get closer to the object and the beeping increases; back away and it decreases. Haptic mode involves two tiny vibrating disk motors attached to small PVC cuffs that fit on the thumb and pinky. These motors will buzz differently based on the person’s proximity to a given object.  If an object is 1 to 2.5 meters away, the pinky motor will vibrate. Closer than that, and it switches over to the thumb motor.

To add to the thriftiness of this project, [Tiendo] re-used other objects where he could. The base of the bracelet is a cuff made from PVC. The nylon chin strap and plastic buckle from a broken bike helmet make it adjustable to fit any wrist. To keep the PVC cuff from chafing, he slipped small pieces from an old pair of socks on to the sides.

It’s easy to see why this project is a finalist in our Best Product contest. It’s a simple, low-cost assistive device made from readily available and recycled materials, and it can be built by anyone who knows a little bit about electronics. Add in the fact that it’s lightweight and frees up both hands, and you have a great product that can help a lot of people. Watch it beep and buzz after the break.

The HackadayPrize2017 is Sponsored by:
Filed under: The Hackaday Prize, wearable hacks

Pouring 1200° Tea: Foundry in a Fire Extinguisher

พุธ, 08/16/2017 - 01:31

Let’s face it — the design of most home foundries leaves something to be desired. Most foundries are great at melting metal, but when it comes to pouring the melt, awkward handling can easily lead to horrific results. That’s why we appreciate the thought that went into this electric melting pot foundry.

Sure, electric foundries lack some of the sex-appeal of gas- or even charcoal-fueled foundries, but by eschewing the open flames and shooting sparks, [Turbo Conquering Mega Eagle] was able to integrate the crucible into the foundry body and create what looks for all the world like a Thermos bottle for molten aluminum.

The body is a decapitated fire extinguisher, while the crucible appears to just be a length of steel pipe. An electric stove heating element is wrapped around the crucible, PID control of which is taken care of by an external controller and solid state relay. Insulated with Pearlite and provided with a handle, pours are now as safe as making a nice cup of 1200° tea.

You’ll perhaps recall that [Turbo Conquering Mega Eagle] has a thing for electric foundries, although we have to say the fit and finish of the current work far exceeds his previous quick-and-dirty build using an old electric stove.

[via r/metalworking]

Filed under: misc hacks, tool hacks