Vintage Rotary Phone Turned Virtual Assistant

November 17, 2018 by 7 Comments

Like many of us, [Zoltan Toth-Czifra] has completely embraced 21st century living. His home is awash in smart gadgets and dodads, from color changing light bulbs to Internet-connected cameras. But he’s also got a soft spot for the look and feel of vintage hardware, like the rotary phone he keeps kicking around to remind him of the old days. He recently decided to bridge these two worlds by turning the rotary phone into a modern voice controlled assistant.

The first piece of the puzzle was getting the old school phone connected to something a bit more modern, namely a Raspberry Pi. He didn’t want to hack the vintage phone apart, so he picked up a Grandstream HT801, an adapter that’s used to convert analog telephones to VoIP. [Zoltan] says this model specifically fit the bill as it had a function that allows you to configure a number to dial as soon the phone is lifted off the hook. This allows the user to just pick up the phone and start talking without having to dial anything manually. If you’re looking to pull off a similar setup, you should check to make sure the adapter has this function before pulling the trigger.

With the rotary phone now talking a more modern protocol, [Zoltan] just needed to get the Raspberry Pi side sorted out. He installed a SIP server so it could communicate with the HT801 adapter, and then got to work putting together his virtual assistant. Rather than plug into an existing system, he rolled his own by combining open source packages for controlling his various smart devices with the aptly named SpeechRecognition library for Python.

Right now he’s only programmed a few commands that his system can respond to for controlling his lights and music, but mentions that the system is modular enough that he can add new functions easily. He’s put the source for his virtual assistant framework up on GitHub, which he notes was written in less than 200 lines of original code by virtue of utilizing existing libraries for a lot of the heavy lifting. Open source is a beautiful thing.

In the past we’ve seen rotary phones go mobile thanks to GSM upgrades and dragged kicking and screaming onto the modern phone network with a built-in Raspberry Pi. But we think there’s something especially appealing about the approach [Zoltan] took which preserves the phone’s original hardware.

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SNES Controller Has A Pi Zero In The Trunk

November 17, 2018 by 7 Comments

We’re no stranger to seeing people jam a Raspberry Pi into an old gaming console to turn it into a RetroPie system. Frankly, at this point it seems like we’ve got to be getting close to seeing all possible permutations of the concept. According to the bingo card we keep here at Hackaday HQ we’re just waiting for somebody to put one into an Apple Bandai Pippin, creating the PiPi and achieving singularity. Get it done, people.

That being said, we’re still occasionally surprised by what people come up with. The Super GamePad Zero by [Zach Levine] is a fairly compelling take on the Pi-in-the-controller theme that we haven’t seen before, adding a 3D printed “caboose” to the stock Super Nintendo controller. The printed case extension, designed by Thingiverse user [Sigismond0], makes the controller about twice as thick, but that’s still not bad compared to modern game controllers.

In his guide [Zach] walks the reader through installing the Raspberry Pi running RetroPie in the expanded case. This includes putting a power LED where the controller’s cable used to go, and connecting the stock controller PCB to the Pi’s GPIO pins. This is an especially nice touch that not only saves you time and effort, but retains the original feel of the D-Pad and buttons. Just make sure the buttons on your donor controller aren’t shot before you start the build.

Adding a little more breathing room for your wiring isn’t the only reason to use the 3D printed bottom, either. It implements a very clever “shelf” design that exposes the Pi’s USB and HDMI ports on the rear of the controller. This allows you to easily connect power and video to the device without spoiling the overall look. With integrated labels for the connectors and a suitably matching filament color, the overall effect really does look like it could be a commercial product.

The SNES controller is an especially popular target for hacks and modifications. From commercially available kits to the wide array of homebrew builds, it there’s plenty of people who want to keep this legendary piece of gaming gear going strong into the 21st century

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High Voltage Measurement Is Shockingly Safe

November 17, 2018 by 9 Comments

With the right equipment and training, it’s possible to safely work on energized power lines in the 500 kV range with bare hands. Most of us, though, don’t have the right equipment or training, and should take great care when working with any appreciable amount of voltage. If you want to safely measure even the voltages of the wiring in your house there’s still substantial danger, and you’ll want to take some precautions like using isolated amplifiers.

While there are other safe methods for measuring line voltage or protecting your oscilloscope, [Jason]’s isolated amplifier method uses high voltage capacitors to achieve isolation. The input is then digitized, sent across the capacitors, and then converted back to an analog signal on the other side. This project makes use of a chip from TI to provide the isolation, and [Jason] was able to build it on a perfboard while making many design considerations to ensure it’s as safe as possible, like encasing high voltage sections in epoxy and properly fusing the circuit.

[Jason] also discusses the limitations of this method of isolation on his site, and goes into a lot of technical details about the circuit as well. It probably wouldn’t get a UL certification, but the circuit performs well and even caught a local voltage sag while he was measuring the local power grid. If this method doesn’t meet all of your isolation needs, though, there are a lot of other ways to go about solving the problem.

A Sneak Peek At Anechoic Chamber Testing

November 17, 2018 by 23 Comments

[Mathieu Stephan] has something new in the works, and while he isn’t ready to take the wraps off of it yet, he was kind enough to document his experience putting the mysterious new gadget through its paces inside an anechoic chamber. Considering the majority of us will never get inside of one of these rooms, much less have the opportunity to test our own hardware in one, he figured it was the least he could do.

If you’re not familiar with an anechoic chamber, don’t feel bad. It’s not exactly the sort of thing you’ll have at the local makerspace. Put simply it’s a room designed to not only to remove echos on the inside, but also be completely isolated from the outside. But we aren’t just talking about sound deadening, the principle can also be adapted to work for electromagnetic waves. So not only is in the inside of the anechoic chamber audibly silent, it can also be radio silent.

This is important if you want to test the performance of things like antennas, as it allows you to remove outside interference. As [Mathieu] explains, both the receiver and transmitter can be placed in the chamber and connected to a vector network analyzer (VNA). The device is able to quantify how much energy is being transferred between the two devices, but the results will only be accurate if that’s the only thing the VNA sees on its input port.

[Mathieu] can’t reveal images of the hardware or the results of the analysis because that would give too much away at this point, but he does provide the cleverly edited video after the break as well as some generic information on antenna analysis and the type of results one receives from this sort of testing. Our very own [Jenny List] has a bit more information on the subject if you’d like to continue to live vicariously through the accounts of others. For the rest of us, we’ll just have to settle for some chicken wire and a wooden crate.

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Etch Your Own Circuit Boards In Your Kitchen

November 16, 2018 by 43 Comments

Right now, you can design a PCB, send it off to a PCB fab, and get professional finished boards in a few days for less than a dollar per square inch. This is fantastic, and it’s the driving force behind ever-dropping costs of hardware development. That’s great and all, but you can make circuit boards at home, easily, and without involving too many toxic chemicals. That’s exactly what [videoschmideo] did, and the results are pretty good.

The process starts with a single-sided copper clad board that would be readily obtainable at Radio Shack if there were any of those around anymore. Once the circuit is designed, the traces and pads are printed (mirrored) out onto sticker backing paper. The toner from your laser printer is transferred to the copper with a clothes iron.

The tricky part about creating a PCB is taking away all the copper you don’t want, and for this tutorial [videoschmideo] is using a vinegar and hydrogen peroxide process. If you’re using stuff you can buy at the grocery store, you’re only getting 3% acetic acid and 3% peroxide, but given enough time and enough peroxide, it’ll do the job. After the board is etched, [videoschmideo] neutralizes the copper acetate produced with aluminum foil. The end product isn’t the safest thing in the world, but aluminum salts are much more environmentally friendly than copper compounds.

Making PCBs at home isn’t anything new, but it’s nice to be reminded that you can do so even with minimal effort and chemicals that you could rinse your mouth with. Once you do, though, you’ll probably have to drill some holes in the board. Yes, you could use a dremel, but a nice small drill press is a pleasure, and well worth the investment.

Analog Clock Goes Digital, Or Vice Versa

November 16, 2018 by 12 Comments

Designing a good clock takes a lot of considerations. It’s not just hands, faces, and numbers anymore; there are also word clocks, electronic clocks, marble clocks, or water clocks, and just about anything else imaginable can be used to tell time. Of course, electronic clocks are great for their versatility, and this one shows off an analog-looking clock that is (of course) digital, leveraging all of the perks of analog with all of the upsides of digital electronics.

One of the key design considerations that [Sasa] had while building this piece was that it needed to be silent. LEDs certainly fit that description, so the decision was made to go with an WS2812b ring. It runs using a STM ST32F103 Nucleo board (and a cheaper version of it in later versions of this clock) which shows a red LED for the current hour, yellow LEDs for the traditional analog clock divisions, a green LED for the current minute, and glows the rest of the LEDs up to the current minute with a rainbow pattern.

This is a really clean, simple build with good design at its core, and would be easy to replicate if you’re looking for an eye-catching clock to build. As a bonus, all of the schematics and code are available on the project site, so everything you need is there. If you’re looking for more inspiration, there are some clocks that are even more unique, like this marble clock that is a work of art — but is anything but silent.

Expanding 3D Printer Bed Stays True Under Fire

November 16, 2018 by 9 Comments

It’s hard to pass up another lesson in good machine design brought to us by [Mark Rehorst]. This time, [Mark] combats the relentless forces of bed deformation due to thermal expansion.

Did you think your printer stayed the same size when it heated up? Well, think again! According to [Mark’s] calculations, when heated, the bed can expand by as much as half a millimeter in the x/y direction. While x/y deformation seems like something we can ignore, that’s not always true. If our bed is rigidly fixed in place, then that change in dimension will only result in a warped bed as it tries to make space for itself.

Don’t give up yet though. As sinister as this problem may seem, [Mark] introduces a classic-but-well-implemented solution: and adjustable kinematic coupling. The kinematic coupling holds the bed at the minimum number of points to keep it rigid while exposing thumbscrews to dial in a level bed. What’s special about this technique is that the coupling holds the bed perfectly rigid whilst allowing it to thermally expand!

This is the beauty of “exact constraint” design. Parts are held together only by the minimum number of points needed to guarantee a specific relationship. Here that relationship is coplanarity between the the nozzle’s x/y plane and the bed. Even when the bed expands this relationship holds. Now that is magic.

With such a flood of 3D printed parts on the market, building a printer has never been easier! Nevertheless, it’s easy to pin ourselves into a corner re-tuning a poor design that skips a foundation on the base principles. If you’re curious about more of these principles behind 3D printer design, check out [Mark’s] thorough walkthrough on the CoreXY design.