Recovering Data From Floppies With Errors

June 3, 2019 by Jenny List 36 Comments

Those of us of advancing years will remember the era of the floppy disc. Maybe not that of the 8-inch drive, but probably its 5.25-inch and certainly its 3.5-inch cousins. Some will remember the floppy disc fondly, while for others there will be recollections of slow and unreliable media with inadequate capacity, whose ability to hold data for any length of time was severely questionable. Add three decades to the time a disc has spent in storage, and those data errors become frequent. The life of a retrocomputing enthusiast hoping to preserve aged software is made extremely difficult by them, and [Michael Steil] has a few tips to help with recovery.

It’s written with specific reference to Commodore 5.25-inch floppies, but aside from some of the specific software, the techniques could be applied to any discs. Most interesting is his explanation of the mechanisms that lead to bad discs or bad sectors, before he looks at some of the mitigations that might be employed. Cleaning the disc or the drive head with alcohol is explored, then taking a dump of the raw data for detailed inspection and disassembly in search of checksum errors. If in your youth a floppy disc was just something you put in a drive and you never investigated further, perhaps this piece will fill in some of the gaps.

If the thought of a stack of Commodore 64 floppies fills you with dread, how about using an emulator?

Header image: PrixeH [CC BY-SA 3.0].

Repairdown: Disklavier DKC500RW Control Unit

June 3, 2019 by Tom Nardi 61 Comments

If you’ve been kind enough to accompany me on these regular hardware explorations, you’ve likely recognized a trend with regards to the gadgets that go under the knife. Generally speaking, the devices I take apart for your viewing pleasure come to us from the clearance rack of a big box retailer, the thrift store, or the always generous “AS-IS” section on eBay. There’s something of a cost-benefit analysis performed each time I pick up a piece of gear for dissection, and it probably won’t surprise you to find that the least expensive doggy in the window is usually the one that secures its fifteen minutes of Internet fame.

But this month I present to you, Good Reader, something a bit different. This time I’m not taking something apart just for the simple joy of seeing PCB laid bare. I’ve been given the task of repairing an expensive piece of antiquated oddball equipment because, quite frankly, nobody else wanted to do it. If we happen to find ourselves learning about its inner workings in the process, that’s just the cost of doing business with a Hackaday writer.

The situation as explained to me is that in the late 1990’s, my brother’s employer purchased a Yamaha Mark II XG “Baby Grand” piano for somewhere in the neighborhood of $20,000. This particular model was selected for its ability to play MIDI files from 3.5 inch floppy disks, complete with the rather ghostly effect of the keys moving by themselves. The idea was that you could set this piano up in your lobby with a floppy full of Barry Manilow’s greatest hits, and your establishment would instantly be dripping with automated class.

Unfortunately, about a month or so back, the piano’s Disklavier DKC500RW control unit stopped reading disks. The piano itself still worked, but now required a human to do the playing. Calls were made, but as you might expect, most repair centers politely declined around the time they heard the word “floppy” and anyone who stayed on the line quoted a price that simply wasn’t economical.

Before they resorted to hiring a pianist, perhaps a rare example of a human taking a robot’s job, my brother asked if he could remove the control unit and see if I could make any sense of it. So with that, let’s dig into this vintage piece of musical equipment and see what a five figure price tag got you at the turn of the millennium.

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I Went To The Moon And All I Got Was This Lousy T-Shirt

June 3, 2019 by Brian Benchoff 8 Comments

It’s been a long time coming but [Fran] finally has a DSKY display, a replica of the user interface display found in the Apollo Guidance Computer. The best part? It’s a t-shirt.

This build is a long, long, time in the making first beginning in 2015 when Fran started investigating the DSKY of the Apollo Guidance Computer. At the time, there were reproductions, but honesty they were all terrible. The reproductions used off-the-shelf seven-segment LEDs or light pipes. The real DSKY was a work of art and at the time probably the most complex electroluminescent display ever created. This led [Fran] to a very special trip to the annex of the Air and Space Museum where she was allowed to inspect a real DSKY display. She got all the measurements, and with some non-destructive investigation, she was able to piece together how this very special display was put together.

With that information, [Fran] was able to figure out that this display was a fairly complex series of silk screens. If it’s silk screen, you can put it on a t-shirt, so that’s exactly what [Fran] did. This used a DIY silk screen jig with phosphorescent inks. It’s not an electroluminescent display, but it does glow in the dark.

While this DSKY t-shirt does glow in the dark, that means it’s not an electroluminescent display like the original DSKY. That said, screen printed electroluminescent displays on a t-shirt aren’t unheard of. Several years ago, a screen printing company did a few experiments with EL displays on wearables. Of course, if you want a real electroluminescent DSKY display, [Ben Krasnow] has a very modern reproduction of the screen printed display. The electronics of [Ben]’s project do not resemble what flew to the moon in any way whatsoever; the original DSKY had relays. That said, we’ve never been closer to a modern recreation of the display from an Apollo Guidance Computer, and we have [Fran] and [Ben]’s work to point us forward.

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Tearing Apart Pulse Transformer Switches

June 3, 2019 by Brian Benchoff 29 Comments

If you like mechanical keyboards, you like switches. Historically, switches were weird, with strange capacitive rubber dome switches in Topre boards, buckling springs in the IBM Model M, and beamsprings in earlier IBM keyboards. This teardown of an HP signal generator has the weirdest keyboard switches ever. They’re being called pulse transformer switches, but they are the strangest, weirdest, and most complicated keyboard switch we’ve ever seen

Mechanically, these keys are mounted on a 1×5 plastic frame with a plunger that presses down on a (brass?) photoetched plate. Mechanically, this is effectively a metal dome keyboard that simply presses a springy bit of metal against a contact on a printed circuit board. That’s the mechanical explanation, the electrical theory of operation is much, much weirder.

Electrically, this keyboard consists of a printed circuit board with two coils underneath each key. The circuit is wired up so two keys are ‘read’ at the same time with a pulse from a multiplexer. This pulse induces a current in the ‘sense’ coil of two individual keys which is sent to a comparator. If both keys are not pressed, the comparator sees a positive and a negative voltage which cancels out, meaning no keys are pressed. If one key is pressed, the metal dome shorts out the transformer underneath the keyboard, meaning only one voltage is seen by the comparator, and that key is registered as being pressed.

This is some crazy keyboard circuitry, and I do not say that lightly. There are ‘acoustic’ keyboards out there which consist of a row of keys striking a metal bar with an acoustic transducer on each end. By measuring the time it takes for the sound of a keypress to reach either end of the metal bar, a keypress can be registered. This is weird and expensive to build, and it’s still simpler than a pulse transformer switch. Check out the video below.

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Animated Pixel Lamp Is A Must For Any Chiptuner’s Bedroom

June 2, 2019 by Lewin Day 5 Comments

Lamps are quite often simple things, designed to light an area and perhaps add a touch of style to a room. Of course, it’s 2019 now, and we don’t need to settle for just that. We can have wildly colored animated lamps if we want to! (French Youtube link, embedded below.)

The lamp in question is the work of [Heliox], who knows her way around an LED or two (hundred). In this build, a string of WS2812 addressable RGB LEDs are hooked up to an Arduino Mega brain. The LEDs are fitted into a round lamp body, with a rectangular diffuser for each one. This creates an attractive pixellated effect and gives the animations a charming 8-bit quality. A thin outer shell is 3D printed in white plastic to further diffuse the light. The top of the lamp rotates an internal potentiometer to control mode selection. There’s also a brightness knob on the bottom if things get a touch too intense.

It’s a tidy build that uses 3D printing and addressable LEDs to quickly and easily create a lamp with a fun retro aesthetic. We could imagine this making a great piece for a hip sitcom apartment. We fully expect to see similar lamps on sale in the next couple of years. Video after the break.

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The Multi Pass Def Con Indie Badge Has A European Flavour

June 2, 2019 by Jenny List 10 Comments

It has been fascinating to watch the rise of the #BadgeLife community in North America, and a little sad when viewed from a European perspective that their creative vibrancy has not quite fully made it across the Atlantic. It’s pleasing therefore to report on something traveling in the opposite direction. We’ve found a #BadgeLife creation that’s as American as they come, but which hides a bit of European flavor under its shell.

The DC27 Multi Pass is a Def Con indie badge themed as a prop from the film The Fifth Element. That is not its only trick though, because under the hood it runs the ESP32-based badge.team, the badge software platform created by the team from the Netherlands who brought us the SHA 2017 and Hacker Hotel 2019 badges. Like those two it sports an e-ink screen and a set of touch buttons, which they’ve very neatly incorporated into the Multi Pass design. The badge.team ecosystem brings with it a fully-functional and stable hackable badge platform with MicroPython apps and an app library (We won’t call it a store, it’s all free!) referred to as the hatchery. There is even a Hackaday logo nickname, should you have one of these badges and wish to identify yourself as a reader.

The launch of a new #BadgeLife badge is always cool, but with the best will in the world it is not in itself news. Where this one does, however, get interesting is that it proves that badge.team is a viable route to getting full event badge functionality into an indie badge without the heartache of creating a software platform. It also serves as a fascinating perspective on why the USA has spawned its artistic badge scene while Europe has less diversity. The whole Def Con experience is extremely expensive, while European hacker camps are relatively not so. There is no need for a European hacker to finance their trip to EMF Camp by selling badges, so for many people, the impetus to create finds its outlet in other directions. It would be nice to think that European badge scene will in time evolve as far as the US one, but meanwhile, it’s good to see the Netherlands community supplying their platform to what we think will be a very interesting Def Con indie badge.

Hackaday Links: June 2, 2019

June 2, 2019 by Brian Benchoff 17 Comments

The works of Shakespeare, Goethe, and Cervantes combined do not equal the genius of Rick And Morty. Actually, the word ‘genius’ is thrown around a bit too much these days. Rick and Morty has surpassed genius. This cartoon is sublime. It is beyond any art that could be created. Now, you might not have a high enough IQ to follow this, but Rick and Morty is, objectively, the best art that can be produced. It just draws upon so much; Rick’s drunken stammering is a cleverly hidden allusion to Dostoevsky’s Netochka Nezvanova, absolutely brilliantly providing the back-story to Rick’s character while never actually revealing anything. Now, you’re probably not smart enough to understand this, but Teenage Engineering is releasing a Rick and Morty Pocket Operator. Only the top percentages of IQs are going to understand this, but this is game-changing. Nothing like this has ever been done before.

The Microsoft IntelliMouse Explorer 3.0 is the high water mark of computer peripheral design. Originally released in 2003, the IntelliMouse Explorer 3.0 was an instant classic. The design is nearly two decades old, but it hasn’t aged a day. That said, mouse sensors have gotten better in the years since, and I believe the original tooling has long worn out. Production of the original IntelliMouse Explorer 3.0 stopped a long time ago. Microsoft tried to revive the IntelliMouse a few years ago using a ‘BlueTrack’ sensor that was ridiculed by the gaming community. Now Microsoft is reviving the IntelliMouse with a good sensor. The Pro IntelliMouse is on sale now for $60 USD.

It has come to my attention that wooden RFID cards exist. This shouldn’t come as a surprise to anyone because wood veneer exists, thin coils of wire exist, and glue exists. That said, if you’re looking for an RFID card you can throw in the laser cutter for engraving, or you just want that special, home-made touch, you can get a wooden RFID card.

Lego has just released an Apollo Lunar Lander set, number 10266. It’s 1087 pieces and costs $99. This is a full-scale (or minifig-scale, whatever) Apollo LEM, with an ascent module detachable from the descent module. Two minifigs fit comfortably inside. Previously, the only full-scale (or, again, minifig-scale) Apollo LEM set was 10029, a Lego Discovery kit from 2003 (original retail price $39.99). Set 10029 saw a limited release and has since become a collectible: the current value for a new kit is $336. The annualized ROI of Lego set 10029-1 is 13.69%, making this new Apollo LEM set a very attractive investment vehicle. I’m going to say this one more time: Lego sets, and especially minifigs, are one of the best long-term investments you can make.

A Weinermobile is for sale on Craigslist. Actually, it’s not, because this was just a prank posted by someone’s friends. Oh, I wish I had an Oscar Mayer Weinermobile.

Rumors are swirling that Apple will release a new Mac Pro at WWDC this week. Say what you will about Apple, but people who do audio and video really, really like Apple, and they need machines with fast processors and good graphics cards. Apple, unfortunately, doesn’t build that anymore. The last good expandable mac was the cheese grater tower, retired in 2013 for the trash can pro. Will Apple manage to build a machine that can hold a video card? We’ll find out this week.