Parallel Processing Was Never Quite Done Like This

June 29, 2019 by Jenny List 64 Comments

Parallel processing is an idea that will be familiar to most readers. Few of you will not be reading this on a device with only one processor core, and quite a few of you will have experimented with clusters of Raspberry Pi or similar SBCs. Instead of one processor doing tasks sequentially, the idea goes, take a bunch of processors and hand out the tasks to be done simultaneously.

It’s a fair bet though that few of you will have designed and constructed your own parallel processing architecture. [BB] sends us a link which though it’s an old one is interesting enough to bring you today: [Michael] created a massively parallel array of Parallax Propeller microcontrollers back in 2008, and he did so on a breadboard.

The Parallax Propeller is an 8-core RISC microcontroller from the company that had found success in the 1990s with the BASIC Stamp, the PIC-based board that was all the rage before Arduino came into the world. In the last decade it was seen as an extremely exciting prospect, but high price and arcane development tools compared to a new generation of low-cost and easy to code competitors meant that it never quite caught on and remains today something of an intriguing oddity. So today’s value in this project lies not in something that you should run out and do yourselves, but instead in what the work tells us about the nuts and bolts of parallel processing architecture. It involves more than simply hooking up a load of chips and hoping for the best, and we gain some insight into the different strategies involved.

The Propeller certainly wasn’t the first attempt at a massively parallel microcontroller, and we doubt it will be the last. We’re certainly seeing microcontrollers with more than one core becoming more mainstream even in our community, but even with those how many of you have made use of the second core in your dual-core ESP32? Is a multicore microcontroller a solution searching for a problem, or will somebody one day crack it and the world will never be the same again? As always, the comments are below.

Power To The Pi 4: Some Chargers May Not Make The Grade

June 28, 2019 by Jenny List 66 Comments

The Raspberry Pi 4 has been in the hands of consumers for a few days now, and while everyone seems happy with their new boards there are some reports of certain USB-C power supplies not powering them. It has been speculated that the cause may lie in the use of pulldown resistors on the configuration channel (CC) lines behind the USB-C socket on the Pi, with speculation that one may be used while two should be required. Supplies named include some Apple MacBook chargers, and there is a suggestion is that the Pi may not be the only device these chargers fail to perform for.

Is this something you should be worried about? Almost certainly not. The Pi folks have tested their product with a wide variety of chargers but it is inevitable that they would be unable to catch every possible one. If your charger is affected, try another one.

What it does illustrate is the difficulties faced by anybody in bringing a new electronic product to market, no matter how large or small they are as an organisation. It’s near-impossible to test for every possible use case, indeed it’s something that has happened to previous Pi models. You may remember that the Raspberry Pi 2 could be reset by a camera flash or if you have a very long memory, that the earliest boards had an unseemly fight between two 1.8 V lines that led to a hot USB chip, and neither of those minor quirks dented their board’s ability to get the job done.

Mistakes happen. Making the change to USB-C from the relative simplicity of micro-USB is a big step for all concerned, and it would be a surprise were it to pass entirely without incident. We’re sure that in time there will be a revised Pi 4, and we’d be interested to note what they do in this corner of it.

Brett Smith Makes Your Life Easier With Hidden Microcontroller Features

June 27, 2019 by Jenny List 37 Comments

There was a time when microprocessors were slow and expensive devices that needed piles of support chips to run, so engineers came up with ingenious tricks using extra hardware preprocessing inputs to avoid having to create more code. It would be common to find a few logic gates, a comparator, or even the ubiquitous 555 timer doing a little bit of work to take some load away from the computer, and engineers learned to use these components as a matter of course.

The nice thing is that many of these great hardware hacks have been built into modern microcontrollers through the years. The problem is you know to know about them. Brett Smith’s newly published Hackaday Superconference talk, “Why Do It The Hard Way?”, aims to demystify the helpful hardware lurking in microcontrollers.

Join us below for a deeper dive and the embedded video of this talk. Supercon is the Ultimate Hardware con — don’t miss your chance to attend this year, November 15-17 in Pasadena, CA.

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The Digital Polaroid SX-70

June 27, 2019 by Jenny List 15 Comments

What do you do if you own an iconic and unusual camera from decades past? Do you love it and cherish it, buy small quantities of its expensive remanufactured film and take arty photographs? Or do you rip it apart and remake it as a modern-day digital camera in a retro enclosure? If you’re [Joshua Gross], you do the latter.

The Polaroid SX-70 is an iconic emblem of 1970s consumer technology chic. A true design classic, it’s a single-lens reflex design using a Polaroid instant film cartridge, and its party trick is that it’s a folding camera which collapses down to roughly the size of a pack of 1970s cigars. It was an expensive luxury camera when it was launched in 1972, and today it commands high prices as a collector’s item.

[Joshua]’s build is therefore likely to cause weeping and wailing and gnashing of teeth among vintage camera enthusiasts, but what exactly has he done? In the first instance, he’s performed a teardown of the SX-70 which should be of interest to many readers in itself. He’s removed the mirror and lens, mounted a Raspberry Pi camera behind the lens mount, and a small LCD monitor where the mirror would be.

A new plastic lens in the original lens housing completes the optics, and the electronics come courtesy of a Pi Zero, battery, and USB hub in the space where the Polaroid film cartridge would otherwise be. Some new graphics and a fresh leather cover complete the build, giving what we’d say is a very tidy electronic Polaroid. On the software side there is a filter to correct for fisheye distortion, and the final photos have a slightly Lomographic quality from the plastic lens.

We like what he’s created with his SX-70 even if we can’t help wincing that he did it to an SX-70 in the first place. Maybe it’s less controversial when someone gives the Pi treatment to a more mundane Polaroid camera.

Accurate Time On Your Pi, The Extreme Way

June 26, 2019 by Jenny List 27 Comments

The Raspberry Pi is an extremely versatile little computer, but even its most ardent fans would acknowledge that there are some areas in which its hardware is slightly lacking. One of these is in the field of timing, the little board has no real-time clock. Users must rely on the on-board crystal oscillator, which is good enough as a microprocessor clock but subject to the vagaries of temperature as it is, not so much as a long-term timepiece.

[Manawyrm] has tackled this problem in a rather unusual way, by dispensing entirely with the crystal oscillator on an older Pi model and instead using a clock derived from a GPS source. The source she’s used is a Leo Bodnar mini precision GPS reference clock, which includes a low-jitter synthesiser that can be set to the Pi’s 19.2 MHz required clock. Unexpectedly this also required a simple LC low-pass filter which was made on a sheet of PCB material, because the Pi at first appeared to be picking up a harmonic frequency. The Pi now has a clock that’s sufficiently stable for tasks such as WSPR transmission without constant referral to NTP or other timing sources to keep it on-track.

It’s a short write-up, but it brings with it a further link to a discussion of different time synchronisation techniques on a Pi including using a kernel module to synchronise with the more common GPS-derived 1PPS signal. We’ve not seen anyone else do this particular mod to a Pi before, but conversely we’ve seen a Pi provide an RF time reference to something else.

You’re Sitting On An Engineering Masterpiece: Chairs As A Design Challenge

June 25, 2019 by Jenny List 26 Comments

If you move as a hardware hacker through the sometimes surprisingly similar world of artists, craftspeople, designers, blacksmiths, and even architects, there’s one piece of work that you will see time and time again as an object that exerts a curious fascination. It seems that designing and building a chair is a rite of passage, and not just a simple chair, but in many cases an interesting chair.

An American-made Windsor chair from the turn of the 19th century. Los Angeles County Museum of Art [Public domain]

Some of the most iconic seating designs that you will be instantly familiar with through countless mass-produced imitations began their lives as one-off design exercises. Yet we rarely see them in our community of hackers and makers, a search turns up only a couple of examples. This is surprising, not least because there is more than meets the eye to this particular piece of furniture. Your simple seat can be a surprisingly complex challenge.

Moving Charis From Artisan to Mass Market

The new materials and mass production techniques of the 19th and 20th centuries have brought high-end design into the hands of the masses, but while wealthy homes in earlier centuries had high-quality bespoke furniture in the style of the day, the traditional furniture of the masses was hand-made in the same way for centuries often to a particular style dependent on the region in which it was produced.

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