Hackaday Links: August 4, 2019

August 4, 2019 by Dan Maloney 22 Comments

Is the hacking community facing a HOPEless future? It may well be, if this report from 2600 Magazine is any indication. The biennial “Hackers On Planet Earth” conference is in serious financial jeopardy after the venue that’s hosted it for years, the Hotel Pennsylvania in Manhattan, announced a three-fold increase in price. Organizers are scrambling to save the conference and they’re asking for the community’s help in brainstorming solutions. Hackaday was at HOPE XI in 2016 and HOPE XII in 2018; let’s HOPE we get to see everyone again in 2020.

If you’ve ever been curious about how a 1970s PROM chip worked, Ken Shirriff has you covered. Or uncovered, as he popped the top off a ceramic MMI 5300 DIP to look at the die within. Closeups of the somewhat cockeyed die reveal its secrets – 1,024 tiny fusible links. Programming was a matter of overloading a particular fuse, turning a 1 into a 0 permanently. It’s a fascinating look at how it used to be done, with Ken’s usual attention to detail in the documentation department.

We had a great Hack Chat this week with Mihir Shah from Royal Circuits. Royal is one of the few quick-turn PCB fabs in the USA, and they specialize in lightning-fast turnaround on bare PCBs and assembled boards. He told us all about this fascinating business, and dropped a link to a side project of his. Called DebuggAR, it’s an augmented reality app that runs on a smartphone and overlays component locations, signal traces, pinouts, and more right over a live image of your board. He’s got a beta going now for iPhone users and would love feedback, so check it out.

With all the cool things you can do with LoRa radios, it’s no wonder that wireless hobbyists have taken to pushing the limits on what the technology can do. The world record distance for a LoRa link was an astonishing 702 km (436 miles). That stood for two years until it was topped, twice in the same day. On July 13th, the record was pushed to 741 km, and a mere five hours later to 766 km. All on a scant 25 mW of power.

Linux distro Manjaro made an unconventional choice regarding which office suite to include, and it’s making some users unhappy. It appears that they’ve dumped LibreOffice from the base install, opting instead to include the closed-source FreeOffice. Worse, FreeOffice doesn’t have support for saving .doc and OpenDocument files; potentially leaving LibreOffice users stranded. Paying for an upgrade to SoftMaker’s Office product can fix that, but that’s hardly free-as-in-beer free. It’s kind of like saying the beer is free, but the mug is an upgrade. UPDATE: It looks like the Manjaro team heard all the feedback and are working on a selector so you can install the office suite of your choice.

Tragic news out of New Hampshire, as amateur radio operator Joe Areyzaga (K1JGA) was killed while trying to dismantle an antenna tower. Local news has coverage with no substantial details, however the hams over on r/amateurradio seem to have the inside line on the cause. It appears the legs of the tower had filled with water over the years, rusting them from the inside out. The tower likely appeared solid to Joe and his friend Mike Rancourt (K1EEE) as they started to climb, but the tower buckled at the weak point and collapsed. K1EEE remains in critical condition after the 40′ (12 m) fall, but K1JGA is now a silent key. The tragedy serves as a reminder to everyone who works on towers to take nothing for granted before starting to climb.

And finally, just for fun, feast your eyes on this movie of the ESA’s Rosetta spacecraft as is makes its flyby of comet 67P/Churyumov–Gerasimenko. It’s stitched together from thousands of images and really makes 67P look like a place, not just a streak of light in the night sky.

Bringing Pro-Level Data Recording To RC Racing

August 4, 2019 by Tom Nardi 7 Comments

We’re all familiar with the “Black Box” used on commercial aircraft, the flight data recorder which captures the minutia of each and every flight on the off-chance that it’s needed in the event of an accident. But even in less dire circumstances, the complete record of the aircraft’s performance versus what was commanded of it by the pilot can be used to fine tune performance or detect faults before they become serious.

As a data engineer for professional motorsports, [Jussi Luopajärvi] knows similar recorders can be just as useful for vehicles stuck here on terra firma. His entry into the 2019 Hackaday Prize, TestLogger, aims to bring that same kind of technology to the world of RC racing. The gadget allows the driver to easily record a wealth of data about the vehicle during races, giving them valuable insight into the vehicle’s performance.

So what kind of variables are there to record on a 1/8th or 1/12th scale car? Don’t be fooled by their diminutive wheelbases, the modern RC car relies on an impressive amount of technical wizardry that benefits from a close eye.

Right now, [Jussi] says TestLogger can record not only obvious elements like battery level and throttle, but also more esoteric variables such as steering input, individual drive wheel speed, angular velocity, and even g-force in three dimensions. There’s also support for a trackside IR beacon that allows TestLogger to record lap times.

All of the data is stored on TestLogger’s SD card in standard CSV files, which makes it easy for us hacker types to parse and analyze. But for those who are more interested in driving than delimiting, there’s also a very slick website that will let users upload and compare their data. This complete user experience gives TestLogger a very professional feel, and we can’t wait to see where [Jussi] takes it from here.

With powerful microcontrollers available for a song, we expect this kind of detailed data collection is only going to become more common.

Doing What Id Couldn’t: Returning Music To Jaguar Doom

August 4, 2019 by Erin Pinheiro 16 Comments

While the rest of the world has by and large forgotten the Atari Jaguar, the generously marketed console still has a fan base, and even some dedicated hackers prodding away at it. [Cyrano Jones] is one of them, and he managed something many considered unthinkable: restoring in-game music to the Jaguar port of Doom.

The Jaguar version of the classic shooter was developed by id Software themselves, and is generally considered one of the better console ports. For example, the large number of buttons on the Jaguar controller allowed players to select weapons directly rather than having to cycle through them. Unfortunately, the complete lack of music during gameplay was a glaring omission that took several points off of an otherwise fairly solid presentation.

The common culprit blamed for this was that the Jaguar’s DSP was already being used for math processing, so it didn’t have any cycles left for music playback. Coupled with a tight deadline, id probably cut their losses and released it without in-game music rather than try and spend more time engineering a solution. To compensate for the lack of in-game music, id did include the famous soundtrack in the intermission screens rather than entirely strip it out.

As [Cyrano] found out by studying the source code that’s been available since 2003, sound effects in the Jaguar version of Doom are played using something called a “ring buffer”: a cyclical fixed-length data buffer which constantly gets outputted as audio. With a patch of unused memory he could fit a second ring buffer in, rendering the music to it with close to no performance hit elsewhere in the code and then mixing both buffers for the final audio output. It looks as though id already had some of this solution in place, but with enough issues that forced them to abandon the idea in order to release the game on time.

Software hacks are not the only things that the Jaguar fan base can do though, and a fine example of a hardware one is this custom mod showing what it could’ve looked like with the CD add-on in an integrated unit.

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Apollo Guidance Computer Saved From The Scrap Yard

August 4, 2019 by Bryan Cockfield 23 Comments

NASA needed a small and lightweight computer to send humans on their journey to the Moon and back, but computers of the day were made out of discrete components that were heavy, large, complicated, and unreliable. None of which are good qualities for spaceflight. The agency’s decision to ultimately trust the success of the Apollo program on the newly developed integrated circuit was an important milestone in computer history.

Given the enormity of the task at hand and the monumental effort it took, it’s surprising to learn that there aren’t very many left in existence. But perhaps not as surprising as the fact that somebody apparently threw one of them in the trash. A former NASA contractor happened to notice one of these historic Apollo Guidance Computers (AGC) at an electronics recycling facility, and thankfully was able to save it from getting scrapped.

The AGC was actually discovered in 1976, but it was decided to get the computer working again in time for the recent 50th anniversary of the Moon landing. A group of computer scientists in California were able to not only get the computer up and running, but integrate it into a realistic simulator that gives players an authentic look at what it took to land on the Moon in 1969.

Restoring a computer of this age and rarity is no easy feat. There aren’t exactly spare parts floating around for it, and the team had to go to great effort to repair some faults on the device. Since we covered the beginning stages of the restoration last year, the entire process has been extensively documented in a series of videos on YouTube. So while it’s unlikely you’ll find an AGC in your local recycling center, at least you’ll know what to do with it if you do.

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Dice Reader Brings Tech To Your Craps Game… Or, Ya Know, D&D

August 4, 2019 by Mike Szczys 5 Comments

There are truisms about dice that you’ve probably already heard: if you have just one of them it’s called a “die”, opposite faces of each die always add up to seven, and those dots that you’re adding together are known as “pips”. But what about the infrared properties of those pips? It turns out they reflect less IR than the white body of the die and that trait can be used to build an automatic die reader.

Great projects have a way of bubbling to the surface. The proof of concept comes from way back in 2009, and while the source blog is now defunct, it’s thankfully been preserved by the Internet Archive. In recreating the project based on that barebones description, [Calvin] reached for a set of five IR transmitter/receiver pairs. Take a close look and you’ll see each transmitter is hidden under its partnered receiver. The light shines up through the receiver and the presence of the pip is detected by measuring how much of it bounces back.

This board is only the sensor portion of the design. A 595 shift register provides the ability to control which IR pair is powered, plus five more signals heading out to the analog pins of an Arduino Uno to monitor how much light is being detected by the receivers. Hey, that’s another interesting fact about dice, you only need to read five different pips to establish the value shown!

We wish there were a demo video showing this in action, but alas we couldn’t find one. We were amused to hear [Calvin] mentioned this was a sorting assignment at University and the team didn’t want to build yet another candy sorter. Look, we love an epic M&M sorter just as much as the next electronic geek, but it’s pretty hard to one-up this dice-based random number generator which rolls 1.3 million times each day.

Reverse Engineering An Ancient SBC With An Apple ][

August 4, 2019 by Jenny List 5 Comments

We spend a lot of time in our community discussing the many home computers from the 8-bit era, while almost completely ignoring their industrial equivalents. While today a designer of a machine is more likely than not to reach for a microcontroller, four decades ago they would have used a single-board computer which might have shared a lot of silicon with the one you used to play Pac Man.

[Epooch] recently came into possession of a CMS 9619A Advanced Single Board Microcomputer, a rather unique Programmable Logic Controller intended for industrial applications. It’s powered by a Motorola 6809 CPU and features the usual array of peripheral chips. To unlock its secrets he reached not for an array of tools from 2019 but for a venerable Apple ][e microcomputer.

In this type of 8-bit machine the various peripherals are enabled through address decoding logic that toggles their chip select line when a particular I/O address is called. Sometimes this task is performed by a set of 74 or similar logic chips, but in the case of the CMS 9619A it falls upon a Programmable Array Logic (PAL). These chips, which could be thought of as a simple precursor to today’s FPGAs, were ideal for creating custom decoding logic.

As you might expect though, a PAL is an opaque device, so to deduce the address map it was necessary to reverse engineer it using the Apple ][‘s printer card and a bit of BASIC code. It then remained to do some ROM disassembly work and wire up the serial ports, before some ROM patching with the Apple ][ as an EPROM programmer to finally access the machine’s debugger.

The 6809 is famous as the brains of Radio Shack’s CoCo and the Dragon computers, but this isn’t the first time we’ve seen it in an SBC.

3D Printed Fan Filter Takes Cues From Costume Scene

August 3, 2019 by Donald Papp 3 Comments

This custom fan filter created by [Kolomanschell] is a clever application of a technique used to create wearable 3D printed “fabrics”, which consist of printed objects embedded into a fine mesh like a nylon weave. The procedure itself is unchanged, but in this case it’s done not to embed 3D printed objects into a mesh, but to embed a mesh into a 3D printed object.

The basic idea is that a 3D print is started, then paused after a few layers. A fine fabric mesh (like tulle, commonly used for bridal veils) is then stretched taut across the print bed, and printing is resumed. If all goes well, the result is 3D printed elements embedded into a flexible, wearable sheet.

The beauty of this technique is that the 3D printer doesn’t need to be told a thing, because other than a pause and resume, the 3D print is nothing out of the ordinary. You don’t need to be shy about turning up the speed or layer height settings either, making this a relatively quick print. Cheap and accessible, this technique has gotten some traction in the costume and cosplay scene.

As [Kolomanschell] shows, the concept works great for creating bespoke filters, and the final result looks very professional. Don’t let the lack of a 3D model for your particular fan stop you from trying it for yourself, we’ve already shared a great resource for customizable fan covers. So if you’ve got a 3D printer and a bit of tulle, you have everything you need for a quick afternoon project.