Partial Relay-Based Calculator Puts The Click Where It Counts

November 3, 2023 by 15 Comments

It looks like [Michal Zalewski] is raising the next generation the right way. First, his eldest son asks for help building a one-bit computer from discrete transistors. Not to be left behind, his little brother then asked for help with an even more retro project, which resulted in this partially relay-based calculator. Maybe there is some hope for the future.

Now, purists will no doubt notice the ATmega64 microcontroller sitting in the middle of the main PCB on this project and cry “Foul!” But perfect is the enemy of done, and as [Michal] explains, at $6 a pop for the Omron relays he and his son chose, there’s only so far you can go with relay logic before you’re taking out a second mortgage. So the relays are limited to the ALU of the calculator, along with the drivers for the six seven-segment LED displays. The microcontroller is just there for housekeeping functions like scanning the keyboard and decoding digits. All the actual calculations are in the relay logic, not silicon. And we’d be remiss not to praise his son’s stylistic choices for this design — that it uses relays with clear covers, and that it has single-sided PCBs with curvy, hand-drawn traces traces that look hand-drawn on old-school yellow substrate. [Michal]’s heart must swell with pride to have fathered someone with such exquisite taste.

For his part, [Mikal] did some really good documentation for this build, including excellent descriptions of Boolean math with half- and full-adders and how relays are used to create the basic logic gates that comprise them. The calculator itself is still a work in progress, with microcontroller code still in development, but it’s working enough that you can enjoy the display driver’s clickiness in the video below. If that doesn’t do it for you, we’ve got other relay calculators to scratch that click itch. Continue reading “Partial Relay-Based Calculator Puts The Click Where It Counts” →

Robot Sunflower Follows The Sun

November 3, 2023 by 15 Comments

Real flowers do it, and even the Beatles did it. [Robo Hub] now has a plastic sunflower that tracks the sun using, of course, an Arduino. It may not qualify as a real robot, but it does mimic a real sunflower. The electronics aren’t earth-shattering, of course. An Arduino, a light sensor, and a servo motor are all you really need. But we enjoyed the whimsy and the artistic sensibility. This would be a great school project, for example. Interesting enough to get kids interested but not so hard as to be undoable. You can see a video of the ersatz flower below.

There are actually a pair of light sensors, as you might expect. That way you can determine which sensor is getting the most light. Obviously, these can’t be on-off sensors. They are, in fact, light-dependent resistors, so you get a nice analog reading.

Of course, you might not need an Arduino for this. A 555 driving a servo and a handful of discrete components could measure a bridge with the photoresistors and get the same effect. On the other hand, a microcontroller these days is inexpensive and versatile, so why not?

Usually, people tracking the sun are trying to get more energy. That doesn’t have to be any more complicated, though.

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Pour One Out For This Bottle-Playing Robot

November 2, 2023 by 5 Comments

If you have an iota of musicality, you’ve no doubt noticed that you can play music using glass bottles, especially if you have several of different sizes and fill them with varying levels of water. But what if you wanted to accompany yourself on the bottles? Well, then you’d need to build a bottle-playing robot.

First, [Jens Maker Adventures] wrote a song and condensed it down to eight notes. With a whole lot of tinkling with a butter knife against their collection of wine and other bottles, [Jens] was able to figure out the lowest note for a given bottle by filing it with water, and the highest note by emptying it out.

With the bottle notes selected, the original plan was to strike the bottles with sticks. As it turned out, 9g servos weren’t up to the task, so he went with solenoids instead. Using Boxes.py, he was able to parameterize a just-right bottle holder to allow for arranging the bottles in a circle and striking them from the inside, all while hiding the Arduino and the solenoid driver board. Be sure to check it out after the break.

Don’t have a bunch of bottles lying around? You can use an Arduino to play the glasses.

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Proposed European Electronic ID Law Raises Concerns

November 2, 2023 by 39 Comments

The harmonisation of standards for electronic identification across the EU should normally be soporific enough to send even the most Club-Mate-hyped hacker straight to sleep, but as Computer Weekly reports, discussion of this reform in the EU corridors of power has caused significant unrest among cyber security experts. Just how can providing Europeans with a harmonised digital ID be so controversial? As you might imagine, the devil lies in the detail.

At issue is the eIDAS Regulation, a system which, in the words of its website: “ensures that people and businesses can use their own national electronic identification schemes (eIDs) to access public services available online in other EU countries,” and “creates a European internal market for trust services by ensuring that they will work across borders and have the same legal status as their traditional paper-based equivalents,” and the point of concern lies with its application to websites. The EU want to ensure that Europeans can digitally verify businesses as well as individuals they deal with, and since that includes websites, they want to insert a provision allowing countries to mandate their own trusted root certificates. At a stroke, this opens the potential for state actors to snoop on all encrypted online traffic, something which would compromise the security of all.

Sadly for Europeans, this isn’t the only questionable online regulation effort from that region.

Thanks [Joyce Ng] for the tip.

The Taylor and Amy Show

The Avon Computer Goth Challenge

November 2, 2023 by 9 Comments

Hot off the heels of their musical debut 6502 song the good folk at the Taylor and Amy Show are at it again. This time instead of assaulting our auditory senses, they play with our perception of color all while keeping the spirit of retro computing alive.

To back up a bit, I had the pleasure of witnessing the discovery of the Avon Beauty Vision Computer while at the Vintage Computer Festival Mid-West (VCFMW) this past September. We had visited the home of our friend [Jim W] from VCFMW who nonchalantly pulled down from the shelf the reddest computer I have ever seen.

A crowd quickly gathered at this newfound treat, designed and built before the invention of the Blue LED, was fallen upon and the process of prying out its secrets began. I was not privy to the negotiations, but I did notice a brightly colored red suitcase being exfiltrated by highly trained operatives later that night.

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Random Number Generator Is A Blast From The Past

November 2, 2023 by 16 Comments

Hackers love random numbers, or more accurately, the pursuit of them. It turns out that computers are so good at following our exacting instructions that they are largely incapable of doing anything that would fit the strict definition of randomness — which has lead to some elaborate methods of generating the unexpected.

Admittedly, the SB42 Random Number Generator built by [Simon Boak] isn’t exactly something you’d be using for cryptography. The method used to generate the digits, a pair of 555 timers sending pulses through linear-feedback shift registers, would at best be considered pseudo-random. Plus the only way of getting the digits out of the machine is by extracting them from the Nixie tubes with your Mark I Eyeballs. But it absolutely excels at the secondary reason many hackers like to build their own randomness rigs — it looks awesome.

Externally, it absolutely nails the look of a piece of vintage DIY year. Down to the classic white-on-black label tape. But open up the hood, and you’re treated to a real rarity these days: wirewrap construction. In an era where you can get PCBs made and shipped to your door for literally pennies, [Simon] is out there keeping the old ways alive. It doesn’t just look the part either. Unlike most modern projects we see, there isn’t a multi-core microcontroller behind the scenes doing all the work, it’s logic gates all the way down.

This isn’t the first random-ish number generator that we’ve seen use shift registers. But if you’re looking for something that might actually pass some randomness checks, and don’t mind working with something a bit spicy, you could check out some of the previous devices we’ve covered that used radioactive decay as an entropy source.

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Pocketable Yagi Antenna Really Shoots For Distance

November 2, 2023 by 45 Comments

For amateur radio operators, the quest for the perfect antenna never seems to end. Perhaps that’s because our requirements are always changing. We never quite seem to get to one design that can do everything. This copper-foil Yagi antenna might not do everything, but it really seems to tick off the boxes for gain and directionality along with ultra-portability.

If you’ve been following [Ben Eadie (VE6SFX)]’s trip down the rabbit hole of lightweight antenna building, you’ll recall that he’s already knocked off a J-pole antenna and a stealthy mobile slot antenna using little more than copper foil tape. Both of those designs performed great, but [Ben] had bigger fish to fry: he wanted to build a directional antenna for the 2-meter band and go for distance. The traditional Yagi-Uda is generally the preferred design for beam antennas, but they tend to be bulky and cumbersome. But with a roll of copper foil tape [Ben] was able to lay out a three-element Yagi on a sheet of Tyvek wrap. Reinforced with some packing tape and stiffened with a couple of fiberglass rods attached to a 3D printed handle, and it was ready to go.

[Ben]’s field test results were most impressive. Not only was he able to open up repeaters up to 90 km away, but he was getting good signal reports to boot. He was even able to reach a repeater 150 km distant, just barely though. Still, that’s mighty impressive performance from something that looks like a Union Jack and rolls up to fit in a pocket.

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