Hackaday Links: September 1, 2024

September 1, 2024 by Dan Maloney 21 Comments

Why is it always a helium leak? It seems whenever there’s a scrubbed launch or a narrowly averted disaster, space exploration just can’t get past the problems of helium plumbing. We’ve had a bunch of helium problems lately, most famously with the leaks in Starliner’s thruster system that have prevented astronauts Butch Wilmore and Suni Williams from returning to Earth in the spacecraft, leaving them on an extended mission to the ISS. Ironically, the launch itself was troubled by a helium leak before the rocket ever left the ground. More recently, the Polaris Dawn mission, which is supposed to feature the first spacewalk by a private crew, was scrubbed by SpaceX due to a helium leak on the launch tower. And to round out the helium woes, we now have news that the Peregrine mission, which was supposed to carry the first commercial lander to the lunar surface but instead ended up burning up in the atmosphere and crashing into the Pacific, failed due to — you guessed it — a helium leak.
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Handheld Oscilloscope Meter Reviewed

August 14, 2024 by Al Williams 24 Comments

We live in a time where there’s virtually no excuse not to have some kind of oscilloscope. As [IMSAI Guy] shows in a recent video, for what you might expect to pay for a decent meter, you can now get one that includes a scope. There are several options out there but it is hard to know how much to spend to get the best possible product. The Zoyi ZT-702S that he looks at costs under $80. But is it worth it?

Scopes that connect to your PC are often very inexpensive. You can also find little toy scopes that use a microcontroller and a little LCD screen. Even though the specs on these are usually appalling, they will still let you visualize what’s happening in a circuit. Sure, you want an expensive bench scope with lots of channels sometimes, but often, you just need to see a signal in broad strokes. Having a scope and a meter together is very handy.

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2024 Tiny Games Contest: Pi-O-Scope-Pong

August 1, 2024 by Donald Papp 3 Comments

[Aaron Lager]’s Pi-O-Scope-Pong project takes a minimal approach to Pong by drawing on an oscilloscope to generate crisp paddles and ball. A Raspberry Pi takes care of the grunt work of signal generation, and even uses the two joysticks of an Xbox controller (connected to the Pi over Bluetooth) for inputs.

Originally, [Aaron] attempted to generate the necessary signals directly from the Pi’s PWM outputs by doing a little bit of RC filtering on the outputs, but was repulsed by the smeary results. The solution? An old but perfectly serviceable 8-bit MAX506 DAC now handles crisping up the visuals with high-quality analog outputs. Code is available on the project’s GitHub repository.

There isn’t any score-keeping or sound, but one thing that it has over the original Pong is a round ball. The ball in the original Pong game was square, but mainly because cost was a concern during design and generating a round ball would have ballooned the part count.

In many ways, Pong itself is a great inspiration for the Tiny Games Challenge, because the simplicity of its gameplay was likely a big part of its success.

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Recovering An Agilent 2000a/3000a Oscilloscope With Corrupt Firmware NAND Flash

June 18, 2024 by Maya Posch 21 Comments

Everyone knows that you can never purchase enough projects off EBay, lest boredom might inadvertently strike. That’s why [Anthony Kouttron] got his mitts on an Agilent DSO-X 2014A digital oscilloscope that was being sold as defective and not booting, effectively just for parts. When [Anthony] received the unit, this turned out to be very much the case, with the front looking like it got dragged over the tarmac prior to having the stuffing beaten out of its knobs with a hammer. Fortunately, repairing the broken encoder and the plastic enclosure was easy enough, but the scope didn’t want to boot when powered on. How bad was the damage?

As [Anthony] describes in the article, issues with this range of Agilent DSOs are well-known, with for example the PSU liking to fry the primary side due to soft power button leaving it powered 24/7 with no cooling. The other is corrupted NAND storage, which he confirmed after figuring out the UART interface on the PCB with the ST SPEAr600 ARM-based SoC. Seeing the sad Flash block decompression error from the Windows CE said enough.

This led him down the rabbithole of finding the WinCE firmware images (nuked by Keysight, backed up on his site) for this scope, along with the InfiniiVision scope application. The former is loaded via the bootloader in binary YMODEM mode, followed by installing InfiniiVision via a USB stick. An alternate method is explained in the SPEAr600 datasheet, in the form of USB BootROM, which can also be reached via the bootloader with some effort.

As for the cause of the NAND corruption, it’s speculated that the scope writes to the same section of NAND Flash on boot, with the SPEAr600’s Flash controller documentation not mentioning wear leveling. Whether that’s true or not, at least it can be fixed with some effort even without replacing the NAND Flash IC.

A Brief Look Inside A Homebrew Digital Sampler From 1979

June 17, 2024 by Dan Maloney 12 Comments

While we generally prefer to bring our readers as much information about a project as possible, sometimes we just have to go with what we see. That generally happens with new projects and work in progress, but it can also happen with old projects. Sometimes very old indeed, as is the case with this digital sampling unit for analog oscilloscopes, circa 1979.

We’ve got precious little to go on with this one other than the bit of eye candy in the video tour below and its description. Luckily, we’ve had a few private conversations with its maker, [Mitsuru Yamada], over the years, enough to piece together a little of the back story here — with apologies for any wrong assumptions, of course.

Built when he was only 19, this sampler was an attempt to build something that couldn’t be bought, at least not for a reasonable price. With no inexpensive monolithic analog-to-digital converters on the market, he decided to roll his own. A few years back he recreated the core of that with his all-discrete successive approximation ADC.

The sampler shown below has an 8-bit SAR ADC using discrete CMOS logic and enough NMOS memory to store 256 samples. You can see the ADC and memory cards in the homebrew card cage made from aluminum angle stock. The front panel has a ton of controls and sports a wide-range attenuator, DC offset, and trigger circuit with both manual and automatic settings.

It’s an impressive build, especially for a 19-year-old with presumably limited resources. We’ve reached out to [Yamada-san] in the hope that he’ll be able to provide more details on what’s under the hood and if this still works after all these years. We’ll pass along whatever we get, but in the meantime, enjoy.

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Schematic of the Pi Pico wireup, showing the various outputs that the firmware will generate on the GPIOs

A Scope Test Tool You Can Build With Just A Pico

May 31, 2024 by Arya Voronova 24 Comments

Ever wanted to see how well your oscilloscope adheres to its stated capabilities? What if you buy a new scope and need a quick way to test it lest one of its channels its broken, like [Paul Wasserman] had happen to him? Now you only need a Pi Pico and a few extra components to make a scope test board with a large variety of signals it can output, thanks to [Paul]’s Sig Gen Pi Pico firmware.

Despite the name it’s not a signal generator as we know it, as it’s not flexible in the signals it generates. Instead, it creates a dozen signals at more or less the same time — from square waves of various frequencies and duty cycles, to a PWM-driven DAC driving eight different waveforms, to Manchester-encoded data I2C/SPI/UART transfers for all your protocol decoder testing.

Everything is open source under the BSD 3-Clause license, and there’s even two PDFs with documentation and a user manual, not to mention the waveform screenshots for your own reference.

It’s seriously impressive how many features [Paul] has fit into a single firmware. Thanks to his work, whenever you have some test equipment in need of being tested, just grab your Pico and a few passive components.

Understand Your Tools: Finger Exercises

April 6, 2024 by Elliot Williams 12 Comments

A dip meter is basically a coil of wire that, when you excite it, you can use to tell if something inside that coil is resonating along. This lets you measure unknown radio circuits to figure out their resonant frequency, for instance. This week, we featured a clever way to make a dip meter with a nanoVNA, which is an odd hack simply because a dip meter used to be a common spare-parts DIY device, while a vector network analyzer used to cost more than a house.

Times have changed, and for the better. Nowadays, any radio amateur can pick up a VNA for less than the cost of all but the cheesiest of walkie talkies, putting formerly exotic test equipment in the hands of untrained mortals. But what good is a fancy-pants tool if you don’t know how to use it? Our own Jenny List faced exactly this problem when she picked up a nanoVNA, and her first steps are worth following along with if you find yourself in her shoes.

All of this reminded me of an excellent series by Mike Szczys, “Scope Noob”, where he chronicled his forays into learning how to use an oscilloscope by running all of the basic functions by working through a bunch of test measurements that he already knew the answer to.

It strikes me that we could use something like this for nearly every piece of measuring equipment. Something more than just an instruction manual that walks you through what all the dials do. Something that takes you through a bunch of example projects and shows you how to use the tool in question through a handful of projects. Because these days, access to many formerly exotic pieces of measuring gear has enabled many folks to have gear they never would have had before – and all that’s missing is knowing how to drive them.