An Arduino And An Enigma All Rolled Into One

December 12, 2019 by Gerrit Coetzee 7 Comments

This hacker has been wanting to design an Enigma machine simulator for a while, but didn’t take the leap until they realized there was a compact Arduino with a surplus of I/O.

The logs go through all sort of variations on the machine. Everything from a plug board variation similar to the original to a 16 segment LED tester are covered. In one of the posts you can even see it decode a real U-Boat message.

The earlier revisions are housed in very attractive laser cut cases but the latest designs employ an even more elegant casing solution. The simulator uses 16 segment displays and momentary push buttons for the keys. At its core is a 2560 Pro mini. The write-up contains a lot of detail about the code behind the Enigma and is interesting to read. Interestingly, the PCB was designed in Fritzing, the EDA software many love to hate.

We love the craftsmanship and attention going into this project and can see it turning into a very appealing kit as it goes through its design cycles.

Supercon SMD Challenge Gets 3D Printed Probes: Build Your Own

December 12, 2019 by Al Williams 2 Comments

This year was the second SMD challenge at Supercon, so it stands to reason we probably learned a few things from last year. If you aren’t familiar with the challenge, you are served some pretty conventional tools and have to solder a board with LEDs getting progressively smaller until you get to 0201 components. Those are challenging even with proper tools, but a surprising number of people have managed to build them even using the clunky, large irons we provide.

During the first challenge, we did find one problem though. The LEDs are all marked for polarity. However, since we don’t provide super high power magnification, it was often difficult to determine the polarity, especially on the smaller parts. Last year, [xBeau] produced some quick LED testers to help overcome this problem. This year we refined them a bit.

As you can see, the 2018 model was a very clever use of what was on hand. A CR2032 holder powered the probes and the probes themselves were two resistors. If you can get the LED to light with the probes you know which lead is the anode and which is the cathode. A little red ink makes it even more obvious. Continue reading “Supercon SMD Challenge Gets 3D Printed Probes: Build Your Own” →

Custom Nixies Perform When Cranked Up To 100,000 Hertz

December 12, 2019 by Dan Maloney 16 Comments

With the popularity of Nixie clocks, we’d be forgiven for thinking that the glowing tubes are only good for applications with a stately pace of change. But we forget that before they became the must-have hobbyist accessory, Nixies were used in all kinds of scientific instruments, from frequency counters to precision multimeters. In such applications, update rates in the hundreds or thousands of Hertz aren’t uncommon, and the humble Nixie handled display refreshes with ease.

But what about refreshing a Nixie at 100 kHz? That was the question put to artisanal Nixie maker [Dalibor Farný] by a client who wanted a timer to calibrate high-speed cameras. It was a feat that [Dalibor] wasn’t sure his custom-made tubes could handle. The video below shows his efforts to find out.

If you ever wanted to know about the physics of gas-discharge displays like the Nixie, the fifteen minutes starting at about 5:13 will give you everything you need. That basic problem boils down to the half-life of excited neon, or how long it takes for half the population of excited molecules to return to the ground state. That, in turn, dictates how long a given cathode will continue to visibly glow after it’s turned off, which determines how many digits will appear illuminated at once.

To answer that, they engaged a company in Prague with a camera capable of a mind-blowing 900,000 frames per second. Even though they found a significant afterglow period for each cathode, even at 100 kHz it’s clear which digit is the one that’s currently illuminated. They also looked at the startup of digits in a cold Nixie versus one that’s warmed up, leading to some fascinating footage at around 26:30.

We appreciate [Dalibor]’s attention to detail, not only in the craftsmanship of his custom tubes but in making sure they’re going to do their job. He recently did a failure analysis on some of his high-end clocks that showed the same care for his product and his brand.

Continue reading “Custom Nixies Perform When Cranked Up To 100,000 Hertz” →

WWII Aircraft Radio Roars To Life: What It Takes To Restore A Piece Of History

December 12, 2019 by Gregory L. Charvat 59 Comments

I’ve been told all my life about old-timey Army/Navy surplus stores where you could buy buckets of FT-243 crystals, radio gear, gas masks, and even a Jeep boxed-up in a big wooden crate. Sadly this is no longer the case. Today surplus stores only have contemporary Chinese-made boots, camping gear, and flashlights. They are bitterly disappointing except for one surplus store that I found while on vacation in the Adirondacks: Patriot of Lake George.

There I found a unicorn of historical significance; an un-modified-since-WW2 surplus CBY-46104 receiver with dynamotor. The date of manufacture was early-war, February 1942. This thing was preserved as good as the day it was removed from its F4F Hellcat. No ham has ever laid a soldering iron or a drill bit to it. Could this unit have seen some action in the south Pacific? Imagine the stories it could tell!

My unconventional restoration of this radio followed strict rules so as to minimize the evidence of repair both inside and out yet make this radio perform again as though it came fresh off the assembly line. Let’s see how I did.

Continue reading “WWII Aircraft Radio Roars To Life: What It Takes To Restore A Piece Of History” →

Sleeper PlayStation Hides A Raspberry Pi 4

December 12, 2019 by Tom Nardi 30 Comments

[Andreas Wilcox] wanted to get his brother a birthday gift that reflected their shared love for the early days of 3D gaming, but just handing him a second-hand original PlayStation lacked a certain style. So he decided to gut the classic system and replace its dated internals with a shiny new Raspberry Pi 4. But rather than taking the easy way out, he put in the time and effort to integrate the new hardware so seamlessly that the nearly 25 year old console still looks stock from the outside.

The fact that the front ports are functional and work with the original controllers really helps sell the stock look. [Andreas] found a USB to PlayStation controller adapter, liberated the PCB, and soldered it to the back of the system’s ports. Even the memory card slots got in on the action, thanks to female USB connectors installed where the original connector went. It was a tight fit, but the final result was well worth it.

We also love the GPIO-controlled cooling fan complete with a duct designed to blow across the notoriously toasty Pi, and check out that carefully designed holder for the power and reset buttons. This entire project is really a fantastic example of how 3D printed parts can give your projects a far cleaner and more professional look than the hacker’s old standby of hot glue; though of course it demands a considerable time investment.

This isn’t the first time we’ve seen a Raspberry Pi shoehorned into a classic video game console, but it’s absolutely one of the cleanest examples we’ve ever seen. Though if we lump Raspberry Pi portables into the running, the competition is considerably fiercer.

Are You Getting Your Money’s Worth From Threaded Inserts?

December 12, 2019 by Dan Maloney 14 Comments

Have you ever wondered whether it’s worth the time and expense to install threaded inserts into your 3D-printed projects? [Stefan] from CNC Kitchen did, and decided to answer the question once and for all, with science.

If this sounds familiar, it’s with good reason: we covered [Stefan]’s last stab at assessing threaded inserts back in March. Then, he was primarily interested in determining if threaded inserts are better than threads cut or printed directly into parts. The current work is concerned with the relative value of different designs of threaded inserts. He looked at three different styles of press-in inserts, ranging in price from pennies apiece to a princely 25 cents. The complexity of the outside knurling seems not to be correlated with the price; the inserts with opposed helical knurls seem like they’d be harder to manufacture than the ones with simple barbs on the outside of the barrel, but cost less. And in fact, the mid-price insert outperformed the expensive one in pull-out tests. Surprisingly, the cheapest inserts were actually far worse at pull-out resistance than printing undersized holes and threading an M3 screw directly into the plastic.

[Stefan] also looked at torque resistance, and found no substantial difference between the three insert types. Indeed, none of the inserts proved to be the weak point, as the failure mode of all the torque tests was the M3 bolt itself. This didn’t hold with the bolt threaded directly into the plastic, of course; any insert is better than none for torque resistance.

We enjoyed seeing [Stefan]’s tests, and appreciate the data that can help us be informed consumers. [John] over at Project Farm does similar head-to-head tests, like this test of different epoxy adhesives.

Continue reading “Are You Getting Your Money’s Worth From Threaded Inserts?” →

Reverse Engineering An Old Bus Display

December 11, 2019 by Tom Nardi 14 Comments

When his makerspace was gifted a pair of Luminator LED signs of the sort you might see on the front of a bus, [PWalsh] decided to pull one apart to see what made it tick. Along the way, he managed to reverse engineer its control protocol and replace its original control board with a WiFi-connected Raspberry Pi. Now they can use the LED signs to show whatever they want; no bus required.

As they were designed for automotive use, the signs were wired for 12 volts DC. So the first order of business was fitting it with an AC/DC converter so it could be plugged into the wall. After he measured the display’s current consumption, [PWalsh] estimated it’s maximum energy consumption and determined an old ATX computer power supply was more than up to the task.

With the sign happily running battery-free, he could begin figuring out how to talk to it. Noticing a MAX485 RS-485 converter on the PCB, gave a pretty good idea of what language it was speaking, and with the aid of his trusty oscilloscope, he was able to suss out the baud rate. A cheap USB to RS-485 converter was then wired in between the sign and its control board so he could sniff the data passing over the line.

From there, the final piece of the puzzle was studying the captured data and figuring out the protocol. [PWalsh] was able to identify packet headers and ASCII characters, and pretty soon knew enough about how the sign communicated that he was able to remove the control board entirely and just push text and images to it right from the Pi. He’s even made his framework available for anyone else who might have a similar piece of bus-signage laying around.

Even if you’re not looking to add one of these signs to your lab, this project is a fantastic example of protocol reverse engineering with low-cost tools and simple techniques. We always love to see the process broken down step by step like this, and our hat’s off to [PWalsh] for delivering the goods in a big way.

This isn’t the first time we’ve seen these sort of LED signs get the “Internet of Things” treatment, and if you’re content with a somewhat scaled down version, you could always just build your own display rather than waiting on the local public transit vehicle to get parted out.