Arbitrary Waveforms On The Cheap

August 12, 2023 by 26 Comments

A signal generator that can produce the usual sine, square, and triangle waves is handy and has been a staple of electronic benches for decades. Being able to craft custom signals opens up new horizons, but historically, these instruments were expensive. The price has come down, though, and [Rishin Goswami] made a 5 MHz 8-bit signal generator with 131K data points of arbitrary waveform for a low price: about $20. If you want to spend a bit more, you can improve the output DAC and op amps, but even that should cost well under $100, all in.

This is one of those projects that seems easy until you start digging into it. For example, storing some points and generating signals using any microcontroller isn’t a big deal. But minimizing jitter and maximizing speed with a conventional processor is difficult. That’s why [Rishin] uses a Raspberry Pi Pico. The programmable I/O units are perfect for generating waveform data fast and reliably. You can see the project go through its paces in the video below.

The Pi streams data to an 8-bit DAC. However, it would be easy to improve resolution with a different converter. The DAC0808 also limits the instrument’s sample rate. The processor could likely go much faster if it had a DAC accommodating higher speeds.

This is just a proof-of-concept, so don’t expect fancy GUIs or the ability to import spreadsheets. You control the device from a command-line-like interface. Still, a good example of how to take advantage of the Pi’s hardware. We took a shot at a similar device nearly a decade ago. Those programmable I/O blocks are finding uses in some surprising applications.

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Throw FreeCAD Some Curves

August 12, 2023 by 43 Comments

[Mango Jelly] got a question from someone trying to model a phone box with a complex curved roof. We have to admit that when we saw it, we knew it would be hard to model well. Naturally, there are several ways it could be one, but [Mango Jelly] used the curves workbench in FreeCAD to produce a wireframe of the shape, and you can see how that works in the video below.

The curve bench didn’t sound familiar to us, and that’s because it is an add-on workbench. He starts with a sketch of a curve, constrained to be symmetrical. Then the draft workbench allowed a rotation to convert the curve into a nice skeleton of the curved roof.

The curves workbench can create a Gordon surface over that skeleton. You can extrude that into a solid object. There are still some details to add, though, and you’ll see how each part of the roof takes shape.

Watching videos like this reminds us that we use a small fraction of what FreeCAD can do. You’ll probably pick up at least one tip from this video. If you need a quick basic tutorial, try the one from [NovaSpirit]. Or, try a longer one.

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Retrotechtacular: Building The First Computers For Banking

August 11, 2023 by 26 Comments

If you’ve ever wondered where the term “banker’s hours” came from, look back to the booming post-war economy of 1950s America. That’s when banks were deluged with so many checks, each of which had to be reconciled by hand, that they had to shut their doors at 2:00 or 3:00 in the afternoon, just to have a hope of getting all the work done at a reasonable time. It was time-consuming, laborious, error-prone work that didn’t scale well, and something had to be done about it.

The short film below, “Manufacturing Competence,” details the building of ERMA, the Electronic Recording Machine, Accounting. ERMA was the result of years of R&D work, and by the early 1960s, General Electric was gearing up production at its new Phoenix, Arizona plant. The process goes from bare metal racks and proceeds through to manufacturing the many modules needed for these specialized machines, which were perhaps the first commercial use of computers outside of universities and the military.

The sheer number of workers involved is astonishing, especially in backplane assembly, with long lines of women wielding wire-wrapping guns and following punch-tape instructions for the point-to-point connections. PCB stuffing was equally labor-intensive, with women stuffing boards from a handful of seemingly random components. And the precision needed for some of the steps, like weaving the ferrite core memory, was breathtaking. We really enjoyed the bit where the tiny toroids were bounced into place with a vibrating jig.

The hybrid nature of ERMA, and the assembly methods needed to produce it, are what strike us most about this film. The backplanes were wire-wrapped, but the modules were wave-soldered PCBs. Component leads were automatically formed and trimmed, but inserted by hand. Assembly and testing were directed by punched tape, but results were assessed by eye. Even ERMA itself was prototyped with vacuum tubes, but switched to transistors for production. The transitional nature of electronics in the early 1960s is on full display here, and it offers an interesting perspective on how change in this field can be simultaneously rapid and glacial.

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A Little Bit Of Science History Repeating Itself: Boyle’s List

August 11, 2023 by 24 Comments

In a recent blog post, [Benjamin Breen] makes an interesting case that 2023 might go down in history as the start of a scientific revolution, and that’s even if LK-99 turns out to be a dud. He points to several biomedical, quantum computing, and nuclear fusion news items this year as proof.

However, we aren’t as convinced that these things are here to stay. Sure, LK-99 was debunked pretty quickly, but we swim in press releases about new battery technologies, and new computer advances that we never hear about again. He does mention that we aren’t alone in thinking that as [Tyler Cowen] coined the phrase “Great Stagnation” to refer to the decline in disruptive tech since 1945. Still, [Benjamin] argues that people never know when they live through a scientific revolution and that the rate of science isn’t as important as the impact of it.

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Solar Boat Makes Waves

August 11, 2023 by 11 Comments

The two best days in a boat owner’s life are the day they buy it, and the day they sell it. At least, that’s the common saying among people who actually spend money to buy a boat. [saveitforparts], on the other hand, looks like he’s going to have many more great days on this boat than that since he cobbled it together nearly for free, and he won’t even need to purchase any fuel for it since it runs on solar power.

The build starts with [saveitforparts] heading out to a literal pile of boats in his yard, unearthing an old single-person sailboat, and then fixing the major problems with its hull. With a new coat of red paint, the focus turns to the drivetrain. Propulsion is handled by an electric trolling motor found at an auction for $8 and is powered by an off-the-shelf battery bank provided by a sponsor of his channel. A pair of solar panels (which were traded for) fitted to outriggers keep the battery bank topped off, and there’s plenty of energy left over with this setup to charge drone batteries and other electronics while out on the lake.

[saveitforparts] reports that the single-passenger solar boat is remarkably stable on the water and fairly quick at full speed thanks to its light weight. He even hypothesizes that it could be fished from. The only thing not particularly stable was towing it to the lake, as the rough roads and permanently-attached solar panel outriggers weren’t particularly congruent with each other. If you’re looking for something similar to carry a few passengers, though, have a look at this much larger version.

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Weather Station With Distributed Sensors

August 11, 2023 by 2 Comments

Building a weather station is a fairly common project that plenty of us have taken on, and for good reason. They can be built around virtually any microcontroller or full-scale computer, can have as many or few sensors as needed, and range from simple, straightforward projects to more complex systems capable of doing things like sending data off to weather services like Weather Underground. This weather station features a few innovations we don’t often see, though, with a modular and wireless design that makes it versatile and easy to scale up or down as needed.

Each of the modules in this build use the ESP32 platform, which simplifies design and also takes care of the wireless capability needed. The base station gets a few extra sensors including those for carbon dioxide, volatile organic compounds, and nitrogen oxides. It also includes a screen which can be used to display a wide variety of data gathered locally but also includes forecast information fetched from the free OpenWeatherMap API. For the sensor modules, BME280 sensors are used for temperature, pressure, and humidity and each module includes its own solar panel and battery with the ESP32 chips set to operate using as little energy as possible.

One of the things that helps easily integrate all of the sensor modules is the use of ESP-NOW, which we have seen a few times before. It essentially eliminates the need for a router and allows ESP modules to connect directly with one another. The build also goes into detail about most of the aspects of this project including the programming of the GUI that the ESP32 base station displays on its screen, so for anyone looking to start their own weather station project this should be an excellent guide. Make sure to check out this one as well if you want to send all of your weather data to Weather Underground.

Hackaday Prize 2023: Circuit Scout Lends A Hand (Or Two) For Troubleshooting

August 11, 2023 by 13 Comments

Troubleshooting a circuit is easy, right? All you need is a couple of hands to hold the probes, another hand to twiddle the knobs, a pair of eyes to look at the schematic, another pair to look at the circuit board, and, for fancy work, X-ray vision to see through the board so you know what pads to probe. It’s child’s play!

In the real world, most of us don’t have all the extra parts needed to do the job right, which is where something like CircuitScout would come in mighty handy. [Fangzheng Liu] and [Thomas Juldo]’s design is a little like a small pick-and-place machine, except that instead of placing components, the dual gantries place probes on whatever test points you need to look at. The stepper-controlled gantries move independently over a fixture to hold the PCB in a known position so that the servo-controlled Z-axes can drive the probes down to the right place on the board.

As cool as the hardware is, the real treat is the software. A web-based GUI parses the PCB’s KiCAD files, allowing you to pick a test point on the schematic and have the machine move a probe to the right spot on the board. The video below shows CircuitScout moving probes from a Saleae logic analyzer around, which lets you both control the test setup and see the results without ever looking away from the screen.

CircuitScout seems like a brilliant idea that has a lot of potential both for ad hoc troubleshooting and for more formal production testing. It’s just exactly what we’re looking for in an entry for the Gearing Up round of the 2023 Hackaday Prize.

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