Hackaday Podcast 154: A Good Enough CNC, Stepper Motors Unrolled, Smart Two-Wire LEDs, A Volcano Heard Around The World

Join Hackaday Editor-in-Chief Elliot Williams and Staff Writer Dan Maloney for this week’s podcast as we talk about Elliot’s “defection” to another podcast, the pros and cons of CNC builds, and making Nixie clocks better with more clicking. We’ll explore how citizen scientists are keeping a finger on the pulse of planet Earth, watch a 2D stepper go through its paces, and figure out how a minimalist addressable LED strip works. From solving a Rubik’s cube to answering the age-old question, “Does a watched pot boil?” — spoiler alert: if it’s well designed, yes — this episode has something for everyone.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct Download (Less than 60 MB)

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Floppy disks

Floppy Interfacing Hack Chat With Adafruit

Join us on Wednesday, February 2 at noon Pacific for the Floppy Interfacing Hack Chat with Adafruit’s Limor “Ladyada” Fried and Phillip Torrone!

When a tiny fleck of plastic-covered silicon can provide enough capacity to store a fair percentage of humanity’s collected knowledge, it may seem like a waste of time to be fooling around with archaic storage technology like floppy disks. With several orders of magnitude less storage capacity than something like even the cheapest SD card or thumb drive, and access speeds that clock in somewhere between cold molasses and horse and buggy, floppy drives really don’t seem like they have any place on the modern hacker’s bench.

join-hack-chatOr do they? Learning the ins and out of interfacing floppy drives with modern microcontrollers is at least an exercise in hardware hacking that can pay dividends in other projects. A floppy drive is, after all, a pretty complex little device, filled with electromechanical goodies that need to be controlled in a microcontroller environment. And teasing data from a stream of magnetic flux changes ends up needing some neat hacks that might just serve you well down the line.

So don’t dismiss the humble floppy drive as a source for hacking possibilities. The folks at Adafruit sure haven’t, as they’ve been working diligently to get native floppy disk support built right into CircuitPython. To walk us through how they got where they are now, Ladyada and PT will drop by the Hack Chat. Be sure to come with your burning questions on flux transitions, MFM decoding, interface timing issues, and other arcana of spinning rust drives.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, February 2 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

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Congratulations Winners Of The 555 Timer Contest!

Sometimes the best inspiration is limitation. The 555 timer does “one thing” — compares a voltage to a couple thresholds and outputs a signal accordingly. It’s two comparators, a voltage ladder, and a flip-flop. And yet, it’s the most sold single chip of all time, celebrating its 50th birthday this year! So when Hackaday runs a 555 Timer Contest, hackers of all stripes come out with their best work to show their love for the Little DIP That Could.

The Winners

Far and away the favorite entry was the Giant 555 Timer by [Rudraksha Vegad]. Every one of our judges rated it in the top five, and it took top honors twice. On its face, this is a simple “giant 555 in a box” build, but have a look under the hood. Each sub-module that makes up the 555 — comparators, flip-flop, and amplifier — are made from salvaged discrete parts in actual breadboard fashion, soldered to brass nails hammered into wood. As an end product, it’s a nice piece of woodworking, but as a process of creation, it’s a masterwork in understanding the 555 at its deepest level. We should all make one!

The Menorah555 is a simple design with some very nice tricks up its sleeve. Perhaps the cutest of which is pulling the central candle out and lighting the others with it — a trick that involves a supercapacitor and reed switches. Each of the candle lighting circuits, however, use a 555 timer both for its intended purpose of providing a timed power-on reset pulse, and another 555 is used as a simple flip-flop. It’s a slick design, and a great user interaction.

The Cyclotone Mechanical Punk Console Sequencer is a rotating tower of circuit sculpture and noisemakers. This one looks great, is amazingly well documented in the video series, and uses a billion clever little tricks along the way. The 555’s role? Each of the four levels is the classic Atari Punk Console circuit.

All three of these projects win a $150 shopping spree at Digi-Key. That’s a lot of timers!

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A screenshot of pinball schematics

Get A Grip On Troubleshooting Your Vintage Pinball Machine

Restoring vintage technology can be a tricky business, especially without the appropriate schematics and documentation. To this end [Mark] has spent the past twelve months building a comprehensive schematic editor and circuit simulator library for electromechanical pinball machines.

Rather than explore each and every table in excruciating detail, the emSim software aims to examine how specific circuits work, and how they are used as part of the gaming experience. The aim of the project is to aid in the diagnosis and repair of vintage electromechanical pinball machines, the types that rely on a dizzying array of switches, gears, motors and coils in their operation, operating like clockwork underneath the play field. While these older pinball machines typically use alternating current, the game logic (for the most part) is still binary, and can be effectively described with Boolean operators.

Like any machine with moving parts, these systems will eventually wear down and require servicing, a task which may not be in the wheelhouse for your casual pinball enthusiast. [Mark]’s hope is that his circuit simulations will allow just about anyone to repair these classic tables, and keep them around for future generations to explore and enjoy.

If tinkering with pinball innards isn’t for you, then make sure to check out our coverage of this awesome virtual pinball table.

Lego Orrery

LEGOpunk Orrery Knows Just The Right Technics

Is the unmistakable sound of the shuffling of LEGO pieces being dug through burned into your psyche? Did the catalog of ever more complex Technic pieces send your imagination soaring into the stratosphere and beyond? Judging by the artful contraption in the video below the break, we are fairly certain that [Marian] can relate to these things.

No doubt inspired by classic orreries driven by clockwork, [Marian]’s LEGO Sun-Earth-Moon orrery is instead driven by either hand cranks or by electric motors. The orrery aims to be astronomically correct. To that end, a full revolution of a hand crank produces a full day’s worth of movement.

Solar and lunar eclipses can be demonstrated, along with numerous other principals such as the tilt of the earth, moon phases, tidal locking, and more, which can be found at the project page.

While classical orreries predate the Victorian era, there seems to be an almost inexplicable link between orreries and the Steampunk aesthetic. But [Marian]’s orrery brought the term “LEGOpunk” to mind. Could it be? Given that there are 2305 pieces and 264 pages of instructions with 436 steps, we think so!

We’ve covered just a few orreries in the past, from this somewhat simple laser cut orrery to this horrifically complex and beautiful thing hereContinue reading “LEGOpunk Orrery Knows Just The Right Technics”

Where The Rubber Meets The Computer

If you ever get a chance to go to Leiden, take it. It is a beautiful little city that hides some high-power university research. It also boasts the world’s first rubber computer. You won’t be running Crysis on it anytime soon, though. The fledgling computer has memory and can count to two — really more of a state machine. It is easier to watch the video below than try to fully explain it. Or you can read through the actual paper.

If you watch the video, you’ll see that deformation in the corrugated rubber structure is apparently repeatable and represent bits in the machine. Pressing and releasing pressure on the structure forms both input and clock and it is possible for the material to go from state A to B on compression, but when you release pressure, it reaches state C. The compression and the angle of the pressure allow for different input conditions. One example rubber state machine counts how many times you compress the piece of rubber.

What do you do with a piece of smart rubber? We don’t know. Maybe if you wanted shoes to count steps so you could transmit the count once a minute to save on battery? The researchers have admitted they don’t have any specific applications in mind either, but presume someone will want to use their work.

Of course, the video’s title: “The Rubber Computer” is a bit of hyperbole, but we can forgive it. Most people wouldn’t get “The Rubber Finite State Machine.” While mechanical computing might seem a bit passe, turns out at the molecular level it may become very important. Besides, you can make a computer out of cardboard (or simulate that computer in an FPGA or spreadsheet, if you prefer).

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The Seductive Pull Of An Obsolete Home Movie Format

It’s dangerous for a hardware hacker to go into a second-hand store. I was looking for a bed frame for my new apartment, but of course I spent an age browsing all the other rubbish treasures on offer. I have a rough rule of thumb: if it’s not under a tenner and fits in one hand, then it has to be exceptional for me to buy it, so I passed up on a nice Grundig reel-to-reel from the 1960s and instead came away with a folding Palm Pilot keyboard and a Fuji 8mm home movie camera after I’d arranged delivery for the bed. On those two I’d spent little more than a fiver, so I’m good. The keyboard is a serial device that’s a project for a rainy day, but the camera is something else. I’ve been keeping an eye out for one to use for a Raspberry Pi camera conversion, and this one seemed ideal. But once I examined it more closely, I was drawn into an unexpected train of research that shed some light on what must of been real objects of desire for my parents generation.

A Thrift Store Find Opens A Whole New Field

One f the surprises comes in just how small this thing is.
One of the surprises comes in just how small this thing is.

The Fuji P300 from 1972 is typical among consumer movie cameras of the day. It takes the form of a film magazine with a zoom lens assembly on its front, a reflex viewfinder on its side, and a handle with a shutter trigger button on it protruding vertically below the magazine and also housing the batteries.

Surprisingly it still has a mercury cell that would have powered its light meter; a minor annoyance to dispose of this correctly. Sometimes these devices had clockwork motors, but this one has an electric motor. It also has a light sensor that is coupled to some kind of electromechanical aperture. It would have been an expensive camera when it was new, probably as much of a purchase as an SLR or a decent mirrorless camera here in 2021.

The surprise came when I opened it up, for it looked like no other 8mm camera I had seen. I’m familiar wit the two reels of a Standard 8 or the boxy cassette of Super 8, but this one used something different. That film magazine is made to fit a compact twin-reel cartridge whose film fits in a metal film gate. This is a Single 8 camera, Fuji’s entry in the all-in-one 8 mm film market, and a format I never knew existed. To explain my unexpected discovery it was necessary to delve into the world of home movie formats in the decade before videotape arrived and drove them out. Continue reading “The Seductive Pull Of An Obsolete Home Movie Format”