Entombed Secrets Partially Unearthed As Researchers Dissect Clever Maze-Generating Algorithm

If you look at enough of another developer’s code, you will eventually say, “What were you thinking, you gosh-darn lunatic?” Now, this exchange can precede the moment where you quit a company and check into a padded room, or it can be akin to calling someone a mad genius and offering them a beer. In the case of [Steven Sidley]’s 1982 game Entombed, [John Aycock] and [Tara Copplestone] found a mysterious table for generating pseudo-random mazes and wrote a whitepaper on how it all works (PDF). The table only generates solvable mazes, but if any bits are changed, the puzzles become inescapable.

The software archaeologists are currently in a labyrinth of their own, in which the exit is an explanation of the table, but the path is overgrown with decade-old vines. The programmer did not make the table himself, and its creator’s name is buried somewhere in the maze. Game cart storage was desperately limited so mazes had to be generated on-the-fly rather than crafted and stored. Entombed‘s ad-hoc method worked by assessing the previous row and generating the next based on particular criteria, with some PRNG in places to keep it fresh. To save more space, the screen was mirrored down the center which doubles the workload of the table. Someday this mysterious table’s origins may be explained but for now, it is a work of art in its own right.

Aside from a table pulled directly from the aether, this maze game leaned on pseudo-random numbers but there is room for improvement in that regard too.

Via BBC Future.

Compiler Explorer, Explored

It wasn’t long ago that we introduced you to a web site, the Godbolt compiler explorer, that allows the visitor to compile code using a slew of compilers and compare their output. We suspect some number of readers said, “Wow! I can use that!”, while perhaps everyone else said, “Huh?” Well if you were in the second group, you ought to watch [What’s a Creel’s] video below where he walks through using the website. He looks at four different algorithms using four different compilers and it is a good example of how you might use the tool to make decisions about how you write software.

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Take A Break From Arduinos, And Build A Radio Transmitter

When you start watching [learnelectronic’s] two-part series about making a radio transmitter, you might not agree with some of his history lessons. After all, the origin of radio is a pretty controversial topic. Luckily, you don’t need to know who invented radio to enjoy it.

The first transmitter uses a canned oscillator, to which it applies AM modulation. Of course, those oscillators are usually not optimized for that service, but it sort of works. In part two he reduces the frequency to 1 MHz at which point it can be listened to on a standard AM radio, before adding an amplifier so any audio source can modulate the oscillator. There’s a lot of noise, but the audio is clearly there.

This is far from practical of course, but combined with a crystal radio it could make an awesome weekend project for a kid you want to hook on electronics. The idea that a few simple parts could send and receive audio is a pretty powerful thing. If you get ready to graduate to a better design, we have our collection.

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Meet MutantC: Raspberry Pi Sidekick Complete With Sliding Screen, QWERTY

Over the years we’ve seen the Raspberry Pi crammed into almost any piece of hardware you can think of. Frankly, seeing what kind of unusual consumer gadget you can shoehorn a Pi into has become something of a meme in our circles. But the thing we see considerably less of are custom designed practical enclosures which actually play to the Pi’s strengths. Which is a shame, because as the MutantC created by [rahmanshaber] shows, there’s some incredible untapped potential there.

The MutantC features a QWERTY keyboard and sliding display, and seems more than a little inspired by early smartphone designs. You know, how they were before Apple came in and managed to convince every other manufacturer that there was no future for mobile devices with hardware keyboards. Unfortunately, hacking sessions will need to remain tethered as there’s currently no battery in the device. Though this is something [rahmanshaber] says he’s actively working on.

The custom PCB in the MutantC will work with either the Pi Zero or the full size variant, but [rahmanshaber] warns that the latest and greatest Pi 4 isn’t supported due to concerns about overheating. Beyond the Pi the parts list is pretty short, and mainly boils down to the 3D printed enclosure and the components required for the QWERTY board:  43 tactile switches and a SparkFun Pro Micro. Everything is open source, so you can have your own boards run off, print your case, and you’ll be well on the way to reliving those two-way pager glory days.

We’re excited to see where such a well documented open source project like MutantC goes from here. While the lack of an internal battery might be a show stopper for some applications, we think the overall form factor here is fantastic. Combined with the knowledge [Brian Benchoff] collected in his quest to perfect the small-scale keyboard, you’d have something very close to the mythical mobile Linux device that hackers have been dreaming of.

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Keeping Kids In School The Smart Way

For institutions with high traffic, such as schools and movie theaters, it can be difficult to keep track of individuals moving in and out, especially without a critical mass of security. For schools especially, keeping track of student attendance and preventing kids from leaving campus in the middle of the day can be a costly problem.

The solution that Tunisian engineers [Michael Djimeli], [Darius Koliou], and [Jinette Tankoua] came up with was to create a smart gate that only turns when checks are carried out by designated security officers. The design is retrofitted to existing school turnstiles in his hometown of Monastir, Tunisia, and uses an RFID card, biometric devices, and a host of access controls to ensure that the student attempting to turn the turnstile is validated first.

The smart gate uses a few methods for identification – either by RFID, fingerprint, facial recognition, or by reading a QR code. An external database stores each user’s data and their transaction history, effectively storing their attendance data. In addition to relaying the information to an administrator, the smart gate also checks the credit of the user — whether they’ve paid the entrance fee for a movie theater, or whether they’re permitted to exit school grounds as a student.

A Raspberry Pi is used as the card collector, relaying information on transaction data over WiFi. Meanwhile local identification information via biometric devices and key fobs are relayed to the processor over Bluetooth. There are also plans to develop a mobile app to track the status of the smart gate remotely.

While the full systems integration isn’t published yet, there are several photos of the control box, which shows the components used for the first smart gate. The mechanical design was successfully tested on the IUC Douala Cameroon university campus (with 35-45 students identified per minute), and the project will hopefully be repeated within more schools in the coming year.

Off-World Cement Tested For The First Time

If the current Administration of the United States has their way, humans will return to the surface of the Moon far sooner than many had expected. But even if NASA can’t meet the aggressive timeline they’ve been given by the White House, it seems inevitable that there will be fresh boot prints on the lunar surface within the coming decades. Between commercial operators and international competition, we’re seeing the dawn of a New Space Race, with the ultimate goal being the long-term habitation of our nearest celestial neighbor.

Schmitt's dusty suit while retrieving samples from the Moon
An Apollo astronaut covered in lunar dust

But even with modern technology, it won’t be easy, and it certainly won’t be cheap. While commercial companies such as SpaceX have significantly reduced the cost of delivering payloads to the Moon, we’ll still need every advantage to ensure the economical viability of a lunar outpost. One approach is in situ resource utilization, where instead of transporting everything from Earth, locally sourced materials are used wherever possible. This technique would not only be useful on the Moon, but many believe it will be absolutely necessary if we’re to have any chance of sending a human mission to Mars.

One of the most interesting applications of this concept is the creation of a building material from the lunar regolith. Roughly analogous to soil here on Earth, regolith is a powdery substance made up of grains of rock and micrometeoroid fragments, and contains silicon, calcium, and iron. Mixed with water, or in some proposals sulfur, it’s believed the resulting concrete-like material could be used in much the same way it is here on Earth. Building dwellings in-place with this “lunarcrete” would be faster, cheaper, and easier than building a comparable structure on Earth and transporting it to the lunar surface.

Now, thanks to recent research performed aboard the International Space Station, we have a much better idea of what to expect when those first batches of locally-sourced concrete are mixed up on the Moon or Mars. Of course, like most things related to spaceflight, the reality has proved to be a bit more complex than expected.

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Alternative Photography Hack Chat

Join us on Wednesday, October 2 at noon Pacific for the Alternative Photography Hack Chat with Pierre-Loup Martin!

It seems like the physics of silicon long ago replaced the chemistry of silver as the primary means of creating photographs, to the point where few of us even have film cameras anymore, and home darkrooms are a relic of the deep past. Nobody doubts that the ability to snap a quick photo or even to create a work of photographic genius with a tiny device that fits in your pocket is a wonder of the world, but still, digital photographs can lack some of the soul of film photography.

Recapturing the look of old school photography is a passion for a relatively small group of dedicated photographers, who ply their craft with equipment and chemistries that haven’t been in widespread use for a hundred years. The tools of this specialty trade are hard to come by commercially, so practitioners of alternate photographic processes are by definition hackers, making current equipment bend to the old ways. Pierre-Loup is one such artist, working with collodion plateshacked large-format cameras, pinholes camera, and chemicals and processes galore –  anything that lets him capture a unique image. His photographs are eerie, with analog imperfections that Photoshop would have a hard time creating.

Join us as Pierre-Loup takes us on a tour through the world of alternative photography. We’ll look at the different chemistries used in alternative photography, the reasons why anyone would want to try it, and the equipment needed to pull it off. Photography was always a hack, until it wasn’t; Pierre-Loup will show us how he’s trying to put some soul back into it.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 2 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.