For Today Only, Pi=3

February 29, 2024 by Jenny List 47 Comments

In 1897 the state assembly of the American state of Indiana famously tried and failed to pass a bill which would have had the effect of denying the value of the mathematical constant Pi. It was an attempt to define a method to “square the circle”, or draw a square of the same area as a given circle through a series of compass and straight edge steps. It’s become something of a running joke and internet meme, and of course defining Pi exactly remains as elusive as ever.

Today and today alone though, you can in one sense claim that Pi is 3, because it’s twelve years since the launch of the original Raspberry Pi. The 29th of February 2012 was a leap day, and today being the third leap day since, could be claimed by a date pedant to be the third birthday of the little board from Cambridge. It’s all a bit of fun, but the Pi folks have marked the occasion by featuring an LED birthday cake.

Three leap days ago, your scribe was up at the crack of dawn to be one of the first to snag a board, only to witness the websites of the two distributors at the time, RS and Farnell, immediately go down under the denial of service formed by many thousands of other would-be Pi owners with the same idea. It would be lunchtime before the sites recovered enough to slowly buy a Pi, and it would be May before the computer arrived.

The Pi definitely arrived with a bang, but at tweleve years old is it still smoking? We think so, while it’s normalized the idea of an affordable little board to run Linux to the extent that it’s one of a crowd, the Pi folks have managed to stay relevant and remain the trend setter for their sector rather than Arduino-style becoming an unwilling collective term.

We’ve said this before here at Hackaday, that while the Pi boards are good, it’s not them alone which sets them apart from the clones but their support and software. Perhaps their greatest achievement is that a version of the latest Raspberry Pi OS can still run on that board ordered in February 2012, something unheard of elsewhere in single board computers. If you still have an original Pi don’t forget this, while it’s not the quickest any more there are still plenty of tasks at which they can excel. Meanwhile with their move into branded silicon and their PCIe architecture move we think things are looking exciting, and we look forward to another 12 years and three birthdays for them. Happy 3rd birthday, Raspberry Pi!

Washing Machine Motors Unlocked

February 29, 2024 by Jenny List 19 Comments

There’s great potential in salvaging a motor from a broken appliance, but so often the part in question is very specific to its application, presenting a puzzle of wires to the experimenter. This was very much the case with older washing machines and other white goods, and while their modern equivalents may have switched to more understandable motors, there are still plenty of the older ones to be had. [Matthias random stuff] sheds a bit of light on how these motors worked, by means of a 1980s Maytag washing machine motor.

Many of us will be used to old-style induction motors, in which two windings were fed out of phase via a large capacitor. This one doesn’t have a capacitor, instead it has a primary winding and a secondary one with a higher resistance. We’re not quite sure the explanation of the resistance contributing to a phase shift holds water, however this winding is connected in for a short time at start-up by a centrifugal switch. Even better, reversing its polarity reverses the direction of the motor.

The result is a mess of wires demystified, and a mains powered motor with a bit of strength for your projects. We’ve let a few of these motors slip through our fingers in the past, perhaps we shouldn’t have been so hasty.

This is a subject that we’ve looked at in the past.

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An Automotive Locksmith On The Flipper Zero And Car Theft

February 29, 2024 by Jenny List 61 Comments

Here in the hacker community there’s nothing we love more than a clueless politician making a fool of themselves sounding off about a technology they know nothing about. A few days ago we were rewarded in spades by the Canadian Minister of Innovation, Science and Industry François-Philippe Champagne, who railed against the Flipper Zero, promising to ban it as a tool that could be used to gain keyless entry to a vehicle.

Of course our community has roundly debunked this assertion, as capable though the Flipper is, the car industry’s keyless entry security measures are many steps ahead of it. We’ve covered the story from a different angle before, but it’s worth returning to it for an automotive locksmith’s view on the matter from [Surlydirtbag].

He immediately debunks the idea of the Flipper being used for keyless entry systems, pointing out that thieves have been using RF relay based attacks which access the real key for that task for many years now. He goes on to address another concern, that the Flipper could be used to clone the RFID chip of a car key, and concludes that it can in the case of some very old vehicles whose immobilizers used simple versions of the technology, but not on anything recent enough to interest a car thief.

Of course, to many readers this will not exactly be news. But it’s still important, because perhaps some of us will have had to discuss this story with non-technical people who might be inclined to believe such scare stories. Being able to say “Don’t take it from me, take it from an automotive locksmith” might just help. Meanwhile there is still the concern of CAN bus attacks to contend with, something the manufacturers could have headed off had they only separated their on-board subsystems.

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The Photodiode You Never Knew You Had

February 28, 2024 by Jenny List 34 Comments

Optoelectronics hold a range of possibilities for the hardware experimenter — indeed who among us hasn’t added LEDs aplenty to our work? What many of us may be unaware of though is that an LED is also a photodiode, and can even be persuaded to generate usable quantities of power. [Voltative] takes a look at this phenomenon with a series of experiments.

Lighting up an LED from a set of other LEDs is pretty cool, as is powering a calculator, or even the calculator powering itself from its on-board LED. But what caught our eye was using two LEDs as a data link, with both of them acting as transmitter and receiver (something on searching we find we’ve seen before). The possibilities there become interesting indeed.

Given that we are now surrounded by LEDs, from OLED screens to LED lighting, we can’t help wondering what the photodiode performance of some other types of part might be. Would the large area of a lighting LED give a better result for example, or would the phosphorescent coating of a white LED make it useless. We feel there’s more scope for experimentation here.

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Classic Calculator Goes RPN, With New Brain

February 27, 2024 by Jenny List 7 Comments

In the era of the smartphone, an electronic calculator may seem a bit old-hat. But they continue to hold a fascination in our community, both when used for their original purpose, and as objects for hardware hacking in their own right. After their first few years when they were a rare and exclusive gadget, they were manufactured in such huge numbers as to be readily available for the curious hacker. [Suikan] has taken one of these plentiful models and done something special for it, creating a new mainboard, and a firmware which transforms it into a reverse Polish, or RPN, scientific calculator.

The Sharp EL210 and EL215 were ubiquitous early-1980s calculators without scientific functions, and with a VFD display. We remember them being common during our schooldays, and they and similar models can still be found on a trawl through thrift stores.

On the board is one of the STM32 microcontrollers and a Maxim VFD driver, and fitting it is simply a case of soldering the Sharp’s VFD to it, placing it in the calculator, and attaching the keyboard. The firmware meanwhile uses the orange C key from the original calculator as a function key, alternating between standard and scientific operations.

If you’re curious about RPN, we’ve taken a look at it here in the past.

There’s Hope For That Cheap Lathe Yet!

February 25, 2024 by Jenny List 30 Comments

There may be few cases where the maxim that “you get what you pay for” rings true, than a lathe. The less you spend on a lathe, the closer you get to a lathe-shaped object and the further from, well, a lathe. [Camden Bowen] has bought a cheap lathe, and he’s not content with a lathe-shaped object, so he takes us in the video below through a set of upgrades for it. In the process he makes a much nicer lathe for an entirely reasonable sum.

First up are the bearings, in this case a set of ball races which aren’t really appropriate for taking lateral force. After a lot of effort and a tiny bit of damage he manages to remove the old bearings and get the new ones in place, though their slightly different dimensions means he has to replace a spacer with a temporary 3D printed item which he’ll turn in metal later. We learn quite a bit about cheap lathe tools and tool alignment along the way, and he ends up buying a better tool post to solve some of its problems. We were always not very good at grinding HSS edges, too.

At the end of it all he has a much better lathe, upping cost from $774 to $1062 which is still pretty good for what he has. Worth a look, if you too have a lathe-shaped object.

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The Book8088 Gets A Post-Hype Review

February 22, 2024 by Jenny List 24 Comments

Last year, a couple of rather unusual computers emerged from China: a 386sx-based palmtop and an 8088-based mini-laptop. The average person isn’t exactly clamoring for a DOS machine these days, but they attracted quite a bit of interest among the retrocomputing scene. Now the dust has settled, [The Retro Shack] has taken a Book 8088 and given it an honest review. Do you need portable 1980s computing in your life, and if so it this the machine to give you it?

The first impression of the machine is just how svelte it is, being like a small but chunky netbook. He explores the hardware and finds as expected an NEC V20 instead of the Intel part running the show, and what would have been a hugely expanded DOS PC back in the day with its VGA and sound card, not to mention a solid state hard drive.

We’re overcome with a bit of nostalgia here at the sight of DOS running Lemmings, and on a machine we’d have given anything to own back in the 1980s. His final conclusion is that it’s a very nice little PC but around $160 seems a little much for what is essentially a toy. We have sadly to agree with him though we really want one, though noting that such a machine would have retailed for a huge amount more than that in 1980s dollars and we’d have considered it a huge bargain then.

If you’re still curious, we covered the arrival of these machines last year.

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