Play A Claw Machine From Your Armchair

Have you ever been seduced by a claw machine in an arcade, only to have your hopes of a cuddly toy dashed as it fails to hang onto your choice? Then you’re in luck, because now you can play to your heart’s content online. [Ryan Walmsley] wants you to control his Raspberry Pi-driven claw machine.

Hardware-wise he’s replaced the original 8052 microcontroller and relay control with the Pi and a custom H-bridge PCB. We particularly light the warning: “Highish voltage”, and we feel it should appear more often. There is some code in his GitHub repository, but we suspect it doesn’t have everything.

We had a lot of fun digging into the documentation on this one. From his initial thoughts through some prototyping and a board failure, to the launch of the online version and finally a run-down of how it all works, he’s got it covered.

Sadly the machine itself isn’t online all the time, it seems to be only online when [Ryan] is at home, so if you live on the other side of the world from his British base you may be out of luck. Fortunately though his previous live streams are online, so you can see it in action on a past outing below the break.

Of course what kind of swag do you load up in a claw machine like this one? On his Twitter feed we’ve seen tests of the aliens from Toy Story (who start their existence in a claw machine so quite fitting). The majority of items show in is recorded games — now numbering over 2000 — have been our beloved companion cube.

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Brits: Make A Vote, Put Cash A Hackerspace’s Way

Those of you who have been involved in the running of a hackerspace or makerspace will know the never-ending struggle to maintain financial solvency, and the quest for sources of income to move your organisation forward. It’s certainly a topic upon which Hackaday’s crew have some experience, more than one of us has helped run a space.

A good avenue to explore lies with community grants: money from organisations on a philanthropic basis to invest in community organisations. These can come from charities, governmental organisations, or even from companies as part of their corporate social responsibility. It’s this last source of grant money that claims our attention today, because we are in the final days of voting for the Aviva Community Fund, in which the British financial and insurance company makes grants for worthy causes across the country. The causes compete to gain as much support as they can, and hope to thus win their prize.

Among the many worthy recipients of the cash are a selection of hackerspaces. First up are Hitchin Hackspace, whose Big Hak full-size rendition of a Milton Bradley Big Trak toy was featured in our coverage of EMF Camp 2016. They are building a new space in what we’ll call a redundant community facility because it sounds better than “Former public toilet”, and winning a grant will help them a lot in that aim.

Then we have East London Makerspace. They have secured an unused garage to turn into a makerspace, as the capital’s population of our community swells to support ever more spaces in its different suburbs. Like Hitchin, the money would go to the essential work involved in creating a functioning space where previously there was nothing.

Finally, we have the unexpected, a heating system from Milton Keynes Men In Sheds. If you know about Men In Sheds as a community organisation for older people, you’ll be wondering why this is listed here. What we haven’t told you is that MK Makerspace is a subgroup of the MK Shed that occupies the upstairs portion of their building, and what warms the Shedders also warms the hacker community of one of Britain’s new towns.

These appear to be the only hackerspaces bidding for grant money, but votes can usefully be given to other allied causes. Linlithgow Remakery and Tool Library, for instance could use a boost, as could the other Men In Sheds groups scattered across the competition.

So if you are one of Hackaday’s British readers, please take a minute to stop by the voting pages listed above, and give them a boost. You have a couple of days to get your votes in, so make them count, and make a difference!

Disclosure: [Jenny List] is a member of Milton Keynes Makerspace.

Huge 74181 is a Classic ALU You Can Actually Understand

You can no longer buy a brand-new 74181, they’ve been out of production for years. All is not lost though, for [Dave’s Dev Lab] have created a facsimile of one on a printed circuit board, using modern single-gate 74-series chips.

Why on earth would you want an oversized replica of an outdated logic chip from nearly five decades ago, we hear you ask? The answer lies in education. If you were to embark on learning about the internals of a microprocessor by taking a modern example such as the one that powers the device on which you are reading this, you would find it to be a daunting task. Over six decades of progress in computer technology have delivered the performance enhancements that put a supercomputer in your smartphone, but at the expense of a contemporary microprocessor being an extremely complex machine which you can’t peer into for any level of understanding.

Simple enough to work your way through the logic

The starting point for the student of microprocessor internals often lies in the past. The technology of the early 1970s holds the fundamentals from which a modern processor can be understood, but remains simple enough to grasp in its entirety as a beginner. Registers, instruction decoders, counters, and an arithmetic/logic unit, or ALU. And for decades the 74181, as an all-in-one 4-bit ALU on a chip that you might have found in a minicomputer at the turn of the 1970s, represented the most convenient way to teach the operation of these devices. Electronic engineers and computer scientists of all ages will have encountered them as they gained their qualifications.

The PCB version of the 181 faithfully follows the original, but with modern 74LVC gates laid out as they would be in the circuit diagram of the chip, and LEDs to show logic state at the different parts of the circuit. Thus when it is used to teach ALU operation it can show every part of the device in detail in a way a real 74181 would never have done.

If the 74181 has caught your interest, we’ve previously brought you [Ken Shirriff]’s reverse engineering of the device in detail using breathtaking images of the silicon.

Your Drone Is Cool, But It’s No Jet Fighter

There are some communities with whom our happy band of hardware hackers share a lot in common, but with whom we don’t often associate. The more workshop-orientated end of the car modification or railway modeler scenes, for instance, or the model aircraft fraternity. Many of these communities exist more for the activity than for the making, some of them dabble with building kits, but among them are a hard core of people who create amazing projects from scratch.

Take [Igor Negoda], for example. Not content with building just any model aircraft, he’s built his own from scratch, to his own design. And if designing for yourself what amounts to a scaled-down jet fighter wasn’t enough, he’s also built his own jet engine to power it. His videos are all in Russian so use YouTube’s subtitle feature if you’re not a Russian speaker, but they’re so good that if you couldn’t access the English translation you’d want to learn the language just to hear his commentary.

The video below the break shows us first a fast-taxi test using a ducted fan, then a full test flight with the jet engine. There is an explanation of the fuel system and the flight control systems, before an impressive flight from what appears to be a former Cold War-era runway. There are a few funny moments such as transporting a large model jet aircraft in a small hatchback car, but the quality of the work in a garage workshop shines through. Suddenly a multirotor doesn’t cut it any more, we want a jet aircraft like [Igor]’s!

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A Dreamcast VMU With A Secret

Since the Raspberry Pi range of boards first appeared back in 2012, we’ve seen them cleverly integrated into a host of inventive form factors. Today we bring you the latest offering in this space, [Kite]’s Raspberry Pi Zero W installed in the case of a Sega Dreamcast VMU. The result is a particularly nicely executed build in which the Pi with a few of its more bulky components removed or replaced with low-profile alternatives sits on the opposite side of a custom PCB from a small LCD display.

The PCB contains the relevant buttons, audio, and power supply circuitry, and when installed in a VMU shell makes for a truly professional quality tiny handheld console. In a particularly nice touch the Pi’s USB connectivity is brought out alongside the SD card on the end of the Zero, under the cap that would have originally protected the VMU’s connector. Some minimal paring away of Sega plastic was required but the case is surprisingly unmodified, and there is plenty of space for a decent-sized battery.

The VMU, or Visual Memory Unit, makes an interesting choice for an enclosure, because it is a relic of one of console gaming’s dead ends. It was the memory card for Sega’s last foray into the console market, the Dreamcast, and unlike those of its competitors it formed a tiny handheld console in its own right. Small games for the VMU platform were bundled with full titles, and there was a simple multiplayer  system in which VMUs could be linked together. Sadly the Dreamcast lost the console war of the late 1990s and early 2000s to Sony’s PlayStation 2, but it remains a console of note.

VMUs are not the most common of gaming survivors, but we’ve shown you one or two projects using them. There was an iPod conversion back in 2010, and much more recently some mind-blowing reverse engineering and emulation on the original VMU hardware.

Thanks [Giles Burgess] for the tip.

UV Sensitive Filament As A Persistent Display

Some of the hacks we feature are modifications of existing devices, others are ground-up builds of entirely new ones. And then there are the experiments, things that have to be worth trying because they just might work. In this final category we have [Matt]’s work with  UV sensitive plastic to form the basis of a simple persistent display, which has created something best described as a proof-of-concept that shows promise, and definitely proves that he had an idea very much worth trying.

The idea makes use of a plastic that changes colour from white to purple when exposed to UV light. He 3D printed a waffle-like structure to locate over a 3×3 grid of UV LEDs, which he could then illuminate under the control of an Arduino Mini Pro. A short illumination changes the colour of the plastic above it, creating a “pixel” that persists for several seconds. In this he has created a working proof of concept for a very simple 3×3 matrix display, albeit rather an unwieldy one. The advantage the idea offers is that a relatively long time of display can be achieved for a relatively short LED illumination, giving a potential for power saving.

The proof-of-concept itself isn’t particularly useful, but from this idea it’s possible a larger display could be practically made. An array of surface-mount LEDs could perhaps illuminate a larger array of plastic to a greater resolution, it’s definitely an idea that was worth trying, and which shows promise for further pursuit. If you’d like to see it in action he’s posted a video, which we’ve placed below the break.

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The VAIO WIth A Pi Inside

Raspberry Pi laptops are not an uncommon sight, as many hardware enthusiasts have shoehorned the tiny board behind LCD panels into home-made cases.

[Frank Adams] has created one of the best Pi laptops we’ve ever seen, (for which we suggest you skip straight to the PDF). He’s removed the guts from an aged Sony VAIO laptop and replaced it with the fruity computer, alongside a Teensy to handle VAIO keyboard, buttons, and LED I/O via the Pi USB port. An M.NT68676 video board interfaces the VAIO display to the Pi HDMI, and a USB to SATA cable is connected to a 240Gb solid state hard drive. The laptop’s Wi-Fi antenna is routed to the Pi via a soldered on co-axial connector, and there is also a real-time clock board. There are a few rough edges such as a USB cable that could be brought inboard, but it’s otherwise well-integrated into the case. His write-up is a very comprehensive PDF, that should serve as a good primer to anyone else considering such a laptop conversion.

The result is a laptop that looks for all the world like a commercially produced machine, yet that is also a Raspberry Pi. In a strange way, a Sony laptop is an apt homecoming for the board from Cambridge, because other than red soldermask or very early Chinese-made models, all Raspberry Pi boards are made in a Sony factory in Wales. Whatever the donor laptop though, this is definitely a step above the run-of-the-mill Pi laptops. To see its competition, take a look at this very ugly machine with a bare LCD panel, or this laser-cut sandwich laptop.