Heartwatch Monitors Your Ticker

July 1, 2018 by Lewin Day 3 Comments

The heart! A pump of the most fantastical kind, it is capable of operating for decades without rest. It’s responsible for supplying vital oxygen to the body’s subsystems, and can be readily monitored with modern technology. [Dave Vernooy] wanted to build a watch that could take heartrate and blood oxygen measurements – so he did.

Named Heartwatch, the device is a DIY smartwatch build with a bunch of exciting features. Heart monitoring is taken care of by the MAX30102 sensor which integrates all the hardware to sense heart rate and oxygen saturation into a single tiny plastic package. There’s then an assortment of accelerometers, gyros and even a color LCD to display all the wonderful information.

It’s all wrapped up in a 3D printed case, with an ATMEGA1284 running the show. The project just goes to show how much can be achieved with an 8-bit processor – there’s not always a need to run a high-powered ARM chip for an embedded project.

There are a fair few DIY smartwatch builds out there – like this classy unit with an OLED screen.

The BBC Computer Literacy Project From The 1980s Is Yours To Browse

June 30, 2018 by Jenny List 12 Comments

In the early 1980s there was growing public awareness that the microcomputer revolution would have a significant effect on everybody’s lives, and there was a brief period in which anything remotely connected with a computer attracted an air of glamour and sophistication. Broadcasters wanted to get in on the act, and produced glowing documentaries on the new technology, enthusiastically crystal-ball-gazing as they did so.

In the UK, the public service BBC broadcaster produced a brace of series’ over the decade probing all corners of the subject as part of the same Computer Literacy Project that gave us Acorn’s BBC Micro, and we are lucky enough that they’ve put them all online so that we can watch them (again, in some cases, if a Hackaday scribe can get away with revealing her age).

You can see famous shows such as the moment when the presenters experienced a live on-air hack while demonstrating an early online service, but most of it is a fascinating contemporary look at the computers we now enthuse over as retro devices. Will the MSX sweep all before it, for example? (It didn’t).

They seem very dated now with their 8-bit micros (if not just for the word “micro”), synth music, and cheesy graphics. But what does come across is the air of optimism, this was the future, and it was packaged not as a threat, but as a good place to be. Take a look, but make sure you have plenty of time. You may spend a while in front of the screen.

We’ve mentioned int he past another spin-off from the Computer Literacy Project, the Domesday Project.

Thanks [Darren Grant] for the tip.

A LIDAR Scanner Build In Glorious Detail

June 29, 2018 by Lewin Day 15 Comments

LIDAR is a very exciting technology that is only just now starting to become accessible to the DIY market. Think radar, but with lasers. There’s a few different modules starting to pop up for just a few hundred dollars. But what is one to do with a LIDAR module? Well, [David] decided to build a room scanner with his Garmin LIDAR Lite, and it’s a wonderful sight to behold.

The scanner consists of a rotating platform, which is driven by a stepper motor. The platform then contains a second motor which runs a tilt axis, upon which the LIDAR is mounted. By aiming the LIDAR in various directions, and recording the detected range, it’s possible to build a point cloud representation of the surrounding area.

The build uses a couple of STM32 chips to do motor control and interface with the LIDAR, but where this build really shines is the mechanical side of things. [David] goes into serious detail about the machining of the parts that make up the rotating system, and there’s plenty of cool bits and pieces like slip rings to make it all work. There’s even some home casting going on here! Be warned, though: there’s some rather juicy close-ups of lathes in action, so put the kids to bed before watching this one all the way through.

We love to see a well-executed build, and even more so when we get to watch the intricate details of how it came together. If you’re still looking for some more inspiration, we’ve seen other LIDAR room scanners before, too.

VCF East XIII: Another Day In Retro Paradise

June 22, 2018 by Tom Nardi 8 Comments

While the weather alternated between mist and monsoon for most of it, the thirteenth annual Vintage Computer Festival East was still a huge success. People came from all over the country, and indeed the world, to show off computers and equipment that was easily older than many of those in attendance. From 1980’s robots to recreations of the very first machines to ever carry the name “computer” as we understand it today, there were a dizzying array of fascinating exhibits to see for those who made the pilgrimage to the InfoAge Science Center in Wall, New Jersey. The people who own and maintain these technological touchstones were in many cases were just as interesting as the hardware they brought to show off; walking encyclopedias of knowledge about the particular piece of vintage gear that they’ve so lovingly shepherded into the modern day.

Through it all, save for a brief intermission to get chili dogs from the nearest WindMill, Hackaday was there. We got up close and personal with [Brian Stuart]’s impressive ENIAC emulator, listened to some ethereal chiptunes courtesy of [Bill Degnan]’s MITS Altair 8800, saw relics from the days when the “app store” needed stamps from [Allan Bushman]’s impressive colleciton, and got inspired by the [Alexander Pierson]’s somewhat more modern take on the classic kit computers of the 1970’s.

But those were’t the only things on display at the Vintage Computer Festival, not by a long shot. There were over 100 individual exhibits this year at VCF, and that doesn’t even include the workshops, classes, tours, or the daily keynote presentations. To say you get your money’s worth on the ticket is something of an understatement.

It’s fair to say that there’s no real substitute for seeing a show like this in person. But in addition to the aforementioned articles, a rundown (in no particular order) of some of the interesting exhibits and attractions from this year’s VCF is a decent consolation prize. If this piques your interest, we’d invite you to keep an eye out for the next Vintage Computer Festival. We’ll be there.

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There’s RC2014 Life In The TMS9918A Display Chip Yet

June 22, 2018 by Jenny List 30 Comments

One of the outliers in the home computer wars of the early 1980s was the Texas Instruments TI99/4A. It may not have had the games library of its rivals and its TMS9900 processor may not have set the world on fire with its registers-in-RAM architecture, but its range of support chips included one whose derivatives would go on to delight subsequent generations. If you had an MSX or one of the 8 or 16-bit Sega consoles, the TMS9918A graphics chip provided the architecture that sat behind Sonic in his adventures.

A few decades later, there is still significant interest in this classic chip. [J.B. Langston] has an RC2014 retrocomputer, and wishing to play MSX demos upon it, has created a TMS9918A-based graphics card for the RC2014 bus. The success of the board hinges upon a circuit showing how to interface the 9918A to SRAM, and since it is mapped to the same ports as its MSX equivalent it should in theory be compatible with Z80 demos written for that platform. He’s already achieved some success with that aim, as can be demonstrated by the video we’ve placed below the break of the Bold MSX demo running on an RC2014.

The RC2014 has gained a significant following in the retrocomputer scene, and has appeared here many times. We reviewed an early model in 2016. Surprisingly though the TMS9918A has only appeared here once, as part of a homebrew 6809-based system.

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When Vortex Rings Collide

June 22, 2018 by Adam Fabio 38 Comments

Intrigued by a grainy video from 1992, [Destin] from Smarter Every Day decided to jump in and fund his own research into the strange phenomenon of vortex ring collisions.

This hack started with a scientific publication and a video from back in 1992. The paper, written by Dr. T T Lim and TB Nichols, illustrated what happens when two vortex rings collide perfectly head-on. The rings collide and spread out forming a thin membrane. Then smaller rings form at a 90-degree angle to the original collision. It’s a beautiful effect when created with multicolored dye in water. But what causes it? There are theories about the fluid mechanics involved, but not much research has gone on since Dr. Lim’s paper.

[Destin] wanted to find out more about the effect, and get some video of it. Being the guy behind Smarter Every Day, he had the high-speed photography equipment and the funds to make that happen. Little did he know that this passion project would take four years to complete.

The initial prototype was built as part of a senior design project by a group of college students. While they did show the phenomenon, it was only barely visible, and not easily repeatable. [Destin] then got an engineer to design and build the experiment apparatus with him. It took numerous prototypes and changes, and years of development.

The final “vortex cannons” are driven by a computer controlled pneumatic cylinder which ensures both cannons get a perfect pulse of air. The air pushes a membrane which moves the dye and water out through an orifice. It’s a very finicky process, but when everything goes right, the result is a perfect collision. Just as in Dr. Lim’s video, the vortexes crash into each other, then form a ring on smaller vortexes.

Destin didn’t stop there. He’s made his data public, in the form of high-speed video – nearly 12 hours worth when played at normal speed. The hope is that researchers and engineers will now have enough information to better understand this phenomenon.

You can check out the videos after the break. If you’re a Smarter Every Day fan, we’ve covered [Destin’s] work in the past, including his backwards brain bike and his work with magnets.

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Dissecting The Elusive Wax Motor

June 18, 2018 by Tom Nardi 34 Comments

We’d wager most readers aren’t intimately acquainted with wax motors. In fact, a good deal of you have probably never heard of them, let alone used one in a project. Which isn’t exactly surprising, as they’re very niche and rarely used outside of HVAC systems and some appliances. But they’re fascinating devices, and once you’ve seen how they work, you might just figure out an application for one.

[AvE] recently did a complete teardown on a typical wax motor, going as far as cutting the thing in half to show the inner workings. Now we’ve seen some readers commenting that everyone’s favorite foul-mouthed destroyer of consumer goods has lost his edge, that his newer videos are more about goofing off than anything. Well we can’t necessarily defend his signature linguistic repertoire, but we can confidently say this video does an excellent job of explaining these little-known gadgets.

The short version is that a wax motor, which is really a linear actuator, operates on the principle that wax expands when it melts. If a solid block of wax is placed in a cylinder, it can push on a piston during the phase change from solid to liquid. As the liquid wax resists compression, the wax motor has an exceptionally high output force for such a small device. The downside is, the stroke length is usually rather short: for the one [AvE] demonstrates, it’s on the order of 2 mm.

By turning heat directly into mechanical energy, wax motors are often used to open valves and vents when they’ve reached a specific temperature. The common automotive engine thermostat is a classic example of a wax motor, and they’re commonly found inside of dishwashers as a way to open the soap dispenser at the proper time during the cycle.

This actually isn’t the first time we’ve featured an in-depth look at wax motors, but [AvE] actually cutting this one in half combined with the fact that the video doesn’t look like it was filmed on a 1980’s camera makes it worth revisiting the subject. Who is going to build a wax motor power device for the Power Harvesting Challenge in the 2018 Hackaday Prize?

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