Author: Jenny List

2978 Articles

An IBM M2 Keyboard Lives Again

July 1, 2024 by 1 Comment

There’s a mystique in old keyboard circles around the IBM Model M, the granddaddy of PC keyboards with those famous buckling spring key switches. The original Model M was a substantial affair with a sheet metal backplane that would probably serve well as a weapon in a zombie apocalypse and still allow writing a Hackaday piece afterward, but later on in the life of these ‘boards there was also a lighter version. The M2 as these models are dubbed has a few known problems, and [Anders Nielsen] scored one online that turned out to have dodgy capacitors. His video, below the break, takes us through the disassembly of his M2 and provides a relaxing tour of these not-quite-so-famous peripherals.

As you’d expect, three-decade-old plastic isn’t always in the best shape, so disassembly and unlatching all those little tabs has to be performed with care. The keys come off and the springs are on show, but we get a nasty shock when they all fall out of place as the top is removed. It appears the rookie mistake is to not turn the ‘board upside down before parting it. Replacing the caps is an easy process after all that, and we get a little dive into the 6805 processors used in model Ms.

If you have a model M of any description then you’re probably at home with the clack-clack-clack sound they make, but have you ever looked at its ancestor, the model F?

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A Vintage AC Bridge Teardown

June 30, 2024 by 2 Comments

If you ever encounter a British engineer of a certain age, the chances are that even if they use a modern DMM they’ll have a big boxy multimeter in their possession. This is the famous Avo 8, in its day the analogue multimeter to have. Of course it wasn’t the only AVO product, and [Thomas Scherrer OZ2CPU] is here with another black box sporting an AVO logo. This one’s an AC bridge, one of a series of models manufactured from the 1930s through to the late 1940s, and he treats us to a teardown and restoration of it.

Most readers will probably be familiar with the operation of a DC Wheatstone Bridge in which two resistances can be compared, and an AC bridge is the same idea but using an AC source. A component under test is attached to one set of terminals while one with a known value is put on the other, and the device can then be adjusted for a minimum reading on its meter to achieve a state of balance. The amount by which it is adjusted can then be used as a measure of the difference between the two parts, and thus the value of an unknown part can be deduced.

In the case of this AVO the AC is the 50Hz (remembering that this is a British instrument) mains frequency, and the reading from the bridge is taken via a single tube amplifier to a rectifier circuit and the meter. Inside it’s a treasure trove of vintage parts with an electrolytic capacitor that looks as though it might not be original, with a selenium rectifier and a copper oxide signal diode in particular catching our eye. This last part is responsible for some reading anomalies, but after cleaning and lubricating all the switches and bringing up the voltage gently, he’s rewarded with a working bridge. You can see the whole story in the video below the break.

Test equipment from this era is huge, so perhaps not all of you have the space for something like this. Some of us have been known to own other AVO products though.

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Can We Ever Achieve Fusion Power?

June 29, 2024 by 51 Comments

Fusion power has long held the promise of delivering near-endless energy without as many unfortunate side effects as nuclear fission. But despite huge investment and some fascinating science, the old adage about practical power generation being 20 years away seems just as true as ever. But is that really the case? [Brian Potter] has written a review article for Construction Physics, which takes us through the decades of fusion research.

For a start, it’s fascinating to learn about the many historical fusion process, the magnetic pinch, the stelarator, and finally the basis of many modern reactors, the tokamak. He demonstrates that we’ve made an impressive amount of progress, but at the same time warns against misleading comparisons. There’s a graph comparing fusion progress with Moore’s Law that he debunks, but he ends on a positive note. Who knows, we might not need a Mr. Fusion to arrive from the future after all!

Fusion reactors are surprisingly easy to make, assuming you don’t mind putting far more energy in than you’d ever receive in return. We’ve featured more than one Farnsworth fusor over the years.

8MM Digitization For Anyone

June 28, 2024 by 8 Comments

There’s a pleasing retro analogue experience to shooting Super 8 film, giving as it does the feel of a 1970s home movie to your work. But once you’ve had the film developed, there’s a need for a projector to enjoy the result. Far better to digitize it for a more modern viewing and editing experience. [Elbert] has made a digitizer for 8mm film which takes the best approach, snapping each frame individually to be joined together in a video file as a whole.

The frame of the device is 3D printed, but some parts of a film transport must be higher quality than a printed part can deliver. These, in particular the sprockets, are salvaged from a film viewer, and the movement is powered by a set of stepper motors. The steppers are controlled by an ESP32, and the optics are provided by a USB microscope. All this is hooked up to a PC which grabs each image, and finally stitches them all together using ffmpeg.

As anyone who has dabbled in 8mm film will tell you, there is a lot in the quality of a film digitizer, and it’s often worth paying for a professional job from someone aimed at the film-making world rather than you local photographic print booth. It would be interesting to take a look at this device, and see whether its quality is worth pursuing. After all, some of us have been known to dabble in 8mm film.

A Previously Unknown Supplier For A Classic Chip

June 27, 2024 by 7 Comments

It’s common enough for integrated circuits to be available from a range of different suppliers, either as licensed clones, or as reverse-engineered proprietary silicon. In the case of a generic circuit such as a cheap op-amp it matters little whose logo adorns the plastic, but when the part in question is an application processor it assumes much more importance. In the era of the 486 and Pentium there were a host of well-known manufacturers producing those chips, so it’s a surprise decades later to find that there was another, previously unknown. That’s just what [Doc TB] has done though, finding a 486 microprocessor from Shenzhen State Micro. That’s not a brand we ever saw in our desktop computers back in the 1990s.

Analysis of a couple of these chips, a DX33 and a DX2-66, shows them to have very similar micro-architecture but surprisingly a lower power consumption suggesting a smaller fabrication process. There’s the fascinating possibility that these might have been manufactured to serve an ongoing demand for 486 processors in some as-yet-unknown Chinese industrial application, but before any retrocomputer enthusiasts get their hopes up, the chips can’t be found anywhere from Shenzhen State Micro’s successor company. So for now they’re a fascinating oddity for CPU collectors, but who knows, perhaps more information on these unusual chips will surface.

Meanwhile we’ve looked at the 486’s legacy in detail  before, even finding there could still just be 486-compatible SoCs out there.

LEGO Bricks: Now Out Of This World

June 27, 2024 by 15 Comments

Now the eyes of space explorers are turned once more towards the Moon, there are a whole host of new engineering challenges facing engineers working on lunar missions. One such challenge relates to how any proposed Moon base might be built, and as European Space Agency (ESA) researchers turn their mind to the problem they’ve taken a uniquely European approach. They’ve made some LEGO bricks.

Sadly lunar regolith is in short supply in Europe at the moment, so as a stand-in they’ve ground up a meteorite, mixed the powder with a polymer, and 3D printed their bricks. The LEGO write-up is a little long on frothy writing style and a little short on the science, but it seems that they clutch in exactly the same way as the official bricks from Billund, and can be assembled just as you would a normal set of bricks.

It’s with some regret that we have to concede that Europe’s off-planet outpost won’t be crewed by LEGO people in a base made from LEGO bricks, but we applaud them for doing this as a practical test given the limited supply of starter material. LEGO themselves have snagged some of them to display in a range of their flagship stores, so we hot-footed it down to London to catch some pictures. What we found is a single brick in a glass case, sadly looking very like any other 3D printed brick in a shiny grey medium. It’s probably the most expensive brick in the world though, so we doubt they’ll be available to buy any time soon.

If you’re hungry for more of all things LEGO, we can do no better than suggest a trip to the mother lode, in Billund, Denmark.

As Cheap As Chips: The MiFare Ultra Light Gets A Closer Look

June 26, 2024 by 8 Comments

If you take public transport in many of the world’s cities, your ticket will be an NFC card which you scan to gain access to the train or bus. These cards are disposable, so whatever technology they use must be astonishingly cheap. It’s one of these which [Ken Shirriff] has turned his microscope upon, a Montreal Métro ticket, and his examination of the MiFare Ultra Light it contains is well worth a read.

The cardboard surface can be stripped away from the card to reveal a plastic layer with a foil tuned circuit antenna. The chip itself is a barely-discernible dot in one corner. For those who like folksy measurements, smaller than a grain of salt. On it is an EEPROM to store its payload data, but perhaps the most interest lies in the support circuitry. As an NFC chip this has a lot of RF circuitry, as well as a charge pump to generate the extra voltages to charge the EEPROM. In both cases the use of switched capacitors plays a part in their construction, in the RF section to vary the load on the reader in order to transmit data.

He does a calculation on the cost of each chip, these are sold by the wafer with each wafer having around 100000 chips, and comes up with a cost-per-chip of about nine cents. Truly cheap as chips!

If NFC technology interests you, we’ve taken a deep dive into their antennas in the past.