Bake It To ReMake It: Cooking Old Magnetic Tape To Recover Data

August 29, 2021 by Dave Rowntree 12 Comments

Those of us old enough may remember the heyday of the text adventure game genre from the first time around. London-based Magnetic Scrolls was an early pioneering company producing titles for the first Amiga and Atari ST platforms. Fast-forward to 2017 and [Hugh Steers], the original co-founder and core developer for Magnetic Scrolls has formed an initiative to revive and re-release the original games on modern platforms. Since the 1980s-era DEC MicroVAX used originally for development is not particularly rare in retro computing circles, and media containing source code was found in someone’s loft space, reviving the games was not a tall order.

First, he needed to recover a copy of the original source code from the backup tapes. But there was a problem, it turns out that the decaying tapes used a unstable polyurethane-based binder to stick the oxide material (which is what stores the data) to the backing tape, and this binder can absorb water over the years.

Not much happens until you try to read the tape, then you trip over the so-called sticky-shed syndrome. Secondly you may find that a small amount of the oxide layer sheds from the tape, coating the read head, rollers and guides inside the complicated tape mechanism. This quickly results in it gumming up, and jamming, potentially chewing up the tape and destroying it permanently.

This was further exacerbated by the behaviour of the DEC TK50Z tape drive, which needed to shuttle the whole length of the tape as part of its normal operation.

A temporary solution was to bake the tape in an oven to drive out the moisture and reduce the stickiness enough to run it through the drive safely. Then only the oxide-shedding problem remained. The TK50Z drive was swapped for a TZ30 which shuttles the tape less, but also critically with a simple hack, would allow the heads to be cleaned with IPA between read passes. This was enough to keep the gumming up at bay and allow enough data to be read from the tapes to recover several games worth of code, ready for the re-releasing process.

The video after the break shows [Rob Jarratt] working through the process of the data recovery.

Continue reading “Bake It To ReMake It: Cooking Old Magnetic Tape To Recover Data” →

an image of the mechanism used to move the curtains

Clever Mechanism Easily Automates Pulling The Blinds

August 29, 2021 by Jim Heaney 15 Comments

There are few things that we all can agree we hate, and the shrill of your alarm clock waking you from a wonderful slumber is definitely high on that list. To wake up more naturally, [nutstobutts] created an automated curtain opener.

The curtain opener is very simple; a stepper motor in the control box pulls a string, which is run to an idler on the far side of the curtain rod and through two clips, attached to the back of each curtain. This design makes it so that both curtains will open smoothly at the same time, and will always come closed again directly in the center. This design is especially favorable for students in dorms or those that live in an apartment, as the installation requires no screws in the wall or permanent modification to the curtains.

The curtains can be opened and closed either by pressing a button on the control box or by sending HTTP requests to the ESP32 that controls everything. This allows for integration with many different IoT systems, for instance [nutstobutts] has been having Home Assistant open the curtains every morning at 6:30 a.m. in lieu of an alarm clock, and then closing them automatically at 9:00 a.m. to help save on cooling costs.

Automated curtains are a great first IoT project if you are looking to just get your feet wet, check out a different style we covered a few months back for more inspiration!

[via r/functionalprint]

DIY Machine Enables PEMF Therapy On A Budget

August 29, 2021 by Tom Nardi 48 Comments

We’re certainly not qualified to say whether or not pulsed electromagnetic field (PEMF) therapy will actually reduce your stress or improve your circulation, but there seems to be enough legitimate research going on out there that it might be worth a shot. After all, unless you’ve got a pacemaker or other medical implant, it seems pretty unlikely a magnetic field is going to make anything worse. Unfortunately commercial PEMF machines can cost thousands of dollars, making it a fairly expensive gamble.

But what if you could build one for as little as $10 USD? That’s the idea behind the simple DIY PEMF machine [mircemk] has been working on, and judging by its ability to launch bits of metal in the video below, we’re pretty confident it’s indeed producing a fairly powerful electromagnetic field. Even if it doesn’t cure what ails you, it should make an interesting conversation piece around the hackerspace.

While the outside of the machine might look a bit imposing, the internals really are exceptionally straightforward. There’s an old laptop power supply providing 19 VDC, a dual-MOSFET board, a potentiometer, and a simple signal generator. The pulses from the signal generator trip the MOSFET, which in turn dumps the output of the laptop power supply into a user-wound coil. [mircemk] has a 17 cm (6.7 inch) open air version wrapped with 200 turns of copper wire used for treating wide areas, and an 8 cm (3 inch) diameter version with 300 windings for when you need more targeted energy.

Some skepticism is always in order with these sort of medicinal claims, but commercial PEMF machines do get prescribed to users to help promote bone growth and healing, so the concept itself is perhaps not as outlandish as it might seem.

Continue reading “DIY Machine Enables PEMF Therapy On A Budget” →

The Curious Case Of The Radio Amateur And The Insulin Pump

August 29, 2021 by Jenny List 93 Comments

A substantial part of gaining and holding an amateur radio licence relates to the prevention of radio interference. In days past this meant interference to analogue television broadcasts, but with ever more complex devices becoming commonplace in homes it applies to much more. This has hit the news in Marion County Florida, where a radio amateur in a senior’s community has shut down his radio station after a potential link emerged between it and another resident’s insulin pump. There is a legal challenge ongoing that relates to the complex’s rules over transmitting antennas.

It’s obviously a serious occurrence for an insulin pump to be affected by anything, and it sounds as though the radio amateur concerned has done the right thing. But it’s clear that something has gone badly wrong in this case whether it’s due to the amateur radio transmissions or not, because for a manufacturer to produce a medical device so easily affected by RF fields should be of concern to everyone. We’d hope that the FCC might take an interest in this story and get to the bottom of it in an impartial manner, because whether it’s the radio amateur at fault, the insulin pump, or something else entirely, it presents a risk to anyone dependent upon such a device.

Perhaps this might also be a case for the ARRL, as we’ve reported before they have some form when it comes to radio investigations.

[Main image source: MailariX, CC-BY-SA 4.0]

1949 Gyroscope Spins Up Again

August 29, 2021 by Al Williams 10 Comments

[Curious Marc] has an Apollo-era gyroscope but isn’t quite ready to put it through this paces without some practice. So he borrowed a 1949 vintage Sperry C5 gyro and did some experiments with it using a 3-phase power supply he plans to use on the other gyro.

There is a little bit of troubleshooting and a lot of gorgeous close up shots of these electromechanical marvels. They sure are noisy, though.

[Marc] wanted a gyro testing table that can control the orientation of a gyro under test. He went the auction route to get a pretty expensive piece of gear for a relatively low price but without the expensive software. In a stroke of luck, he managed to score the required software from the vendor who was intrigued by his project. It looked to us like a table like this wouldn’t be that hard to build from scratch, either.

We are interested in what [Marc] will do with his gyros next. It is hard to imagine that gyros have come from this sort of device to a tiny IC inertial measurement unit that can fit in a phone. Imagine packing the Sperry unit on your next walking robot or self-balancing unicycle.

Need a refresher on how gyro’s work? We got that, too. It even covers the modern kind.

Continue reading “1949 Gyroscope Spins Up Again” →

A computer green screen image of an IRC message of the day

IRC Server For MS-DOS

August 28, 2021 by Chris Wilkinson 17 Comments

The recent flurry of projects based around Internet Relay Chat (IRC) should be a fair indication that the beloved protocol is not going anywhere. Now, thanks to [Mike Chambers], you can add to the IRC ecosystem by hosting your very own MS-DOS based IRC server.

This port of ngIRCd (Next Generation IRC Daemon) has already been spun up on 8088-based PCs running at just 4.77MHz, but you’ll still need at least 640KB of RAM. If your vintage IRC server takes off, you might want to think about dropping in an 10MHz V20 for a bit of a performance boost. Even so, it’s impressive that this server can get up on the 40-year-old IBM 5150, and should absolutely scream on an AT-class system.

The limitations of the 16-bit platform means that SSL and ZLIB are unsupported, and Mike has capped total connections at 50 in his port (however, this limitation can be adjusted by rebuilding from source, should you want to find out how far 640KB of RAM can take you). You’ll also need a few other things to get your server up and running, such as a packet driver for your network card and an mTCP configuration file.

Setting up your own IRC server is arguably a ~~right~~ rite of passage for most hackers and tinkerers, but getting this up and running on a decades-old beige box would make for a fun weekend project. [Mike] has all the juicy details on GitHub, and you can check out a test server running the latest build over at irc.xtulator.com.

Also, don’t forget to visit the #hackaday IRC channel over on irc.libera.chat.

[Thanks Sudos for the hot tip]

Turning Heat Into Electricity

August 28, 2021 by Al Williams 7 Comments

You don’t really create energy, you convert it from one form to another. For example, many ways that we generate electricity use heat from burning or nuclear decay to generate steam which turns a generator. Thermocouples generate electricity directly from heat, but generally not very much. Still, some nuclear batteries directly convert heat to electricity, they just aren’t very efficient. Now researchers have developed a way of preparing a material that is better at doing the conversion: tin selenide.

Tin selenide is known to have good performance converting heat into electricity when in its crystal form. However, practical applications are more likely to use polycrystalline forms, which are known to have reduced conversion performance.

The material works well because it is not very thermally conductive and it has a favorable band structure that allows multiple bands to participate in charge transport. However, in polycrystal configurations, the results are not as good due to higher thermal conductivity. Yet crystalline tin selenide is difficult to manufacture and not very robust in real-world use.

The team worked out that the polycrystal material’s thermal properties were due to tin oxide films on the surface. Using a particular method of construction, you can remove the tin oxide and improve performance even better than the crystal version of tin selenide.

Creating this material might be beyond your garage lab, though. You need a fused silica oven that can reach a pretty tight vacuum. Although you might be able to swing it. Otherwise, you might stick with more conventional methods.