Nixie Shot Timer Adds Useful Elegance To Espresso Machine

March 26, 2021 by 11 Comments

Once you’ve ground the beans and tamped the grounds just so, pulling the perfect shot of espresso comes down to timing. Ideally, the extraction should last 20-30 seconds, from the first dark drips to the tan and tiger-striped crema on top that gives the espresso a full aftertaste.

[Marco] has a beautiful espresso machine that was only missing one thing: an equally beautiful shot timer with a Nixie tube display. Instead of messing with the wiring, [Marco] took the non-invasive approach and is using a DIY coil to detect the magnetic field of the espresso machine’s pump and start a shot timer.

An LM358-based op-amp magnifies the current induced by the machine and feeds it to an Arduino Nano, which does FFT calculations. [Marco] found a high-voltage interface driver to switch 170 V to the Nixies instead of using two handfuls of transistors. Grab yourself a flat white and check it out after the break.

The last Nixies may have been mass-produced in the 1980s, but never fear — Dalibor Farny is out there keeping the dream alive and making new Nixies.

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Real Time Object Detection For $59

March 26, 2021 by 19 Comments

There was a time when making a machine to identify objects in a camera was difficult, even without trying to do it in real time. But now, you can do it with a Jetson Nano board for under $60. How well does it work? Watch [Murtaza’s] video below and see what you think.

The first few minutes of the video piqued our interest, and good thing, too, because the 50 lines of code get a 50-plus minute video! It is worth watching, though, because there’s a lot of good information about how to apply this technique in your own projects.

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Bare-Metal STM32: Please Mind The Interrupt Event

March 26, 2021 by 27 Comments

Interruptions aren’t just a staple of our daily lives. They’re also crucial for making computer systems work as well as they do, as they allow for a system to immediately respond to an event. While on desktop computers these interrupts are less prominent than back when we still had to manually set the IRQ for a new piece of hardware using toggle switches on an ISA card, IRQs along with DMA (direct memory access) transfers are still what makes a system appear zippy to a user if used properly.

On microcontroller systems like the STM32, interrupts are even more important, as this is what allows an MCU to respond in hard real-time to an (external) event. Especially in something like an industrial process or in a modern car, there are many events that simply cannot be processed whenever the processor gets around to polling a register. Beyond this, interrupts along with interrupt handlers provide for a convenient way to respond to both external and internal events.

In this article we will take a look at what it takes to set up interrupt handlers on GPIO inputs, using a practical example involving a rotary incremental encoder.

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Hackaday Podcast 111: 3D Graphics Are Ultrasonic, Lobotomizing Alexa, 3D-Printing Leaky Rockets, And Gaming The Font System

March 26, 2021 by 4 Comments

Hackaday editors Mike Szczys and Elliot Williams curate a week of great hacks. Physical displays created in 3D space are a holy grail, and you can make one with 200 ultrasonic transducers, four FPGAs, and a lot math. Smart speakers have one heck of a microphone array in them, it’s yours for the hacking if you just roll your own firmware. Hobby servos can be awful, but this week we saw they can be made really great by cracking open the DC motor to add a simple DIY position sensor. And lasers are making their way into car headlights; we illuminate the situation in this episode.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (~60 MB)

Places to follow Hackaday podcasts:

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Serial Silicone Molding

March 26, 2021 by 5 Comments

The techniques for making single-digit quantities of custom molded parts don’t scale well when you need to make dozens, as [Kevin Holmes] discovered. He needed to make 80-some sets of a silicone motor mount, and the one-up mold process was not going to work. He explores several solutions, which he rejects as being too complicated. Finally [Kevin] comes up with the idea of daisy-chaining banks of molds clamped together with rails of stock metal bars. It’s a pretty nifty process to watch and you can check the video out below, which is not unlike a very slow 7495 four-bit shift register.

Even though the silicone he uses is clear, pay attention and you can still see the carry-out as it propagates from mold to mold. He manually performs the nibble carry operation from one bank to the next — we wonder if he could cascade these banks, and inject all 80 in one really big squeeze?

Why would someone need 80 sets of silicone rubber motor mounts, you may ask? Well, you may remember the 4-mation 3D zoetrope that we wrote about back in 2018. [Kevin] is one of the founders of this mesmerizing project, and it would seem that their Kickstarter project has been successful. As he demonstrates in the video below, without some type of noise dampening mounts, a rumble from the motor is amplified through the stage of the zoetrope. If you have any favorite mold-making tips for small batch manufacturing, let us know in the comments below. Thanks to [George Graves] for sending this tip our way.

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This Week In Security: XcodeSpy, Insecure SMS, And Partial Redactions

March 26, 2021 by 25 Comments

There seems to be a new trend in malware, targeting developers and their development and build processes. The appeal is obvious: rather than working to build and market a malicious application, an attacker just needs to infect a development machine. The hapless infected developers can now do the hard work to spread the malicious payload.

The newest example is XcodeSpy, discovered by a researcher who chose to remain anonymous. It works by using the Xcode IDE’s Run Script function to, well, run a script that completely backdoors your computer. The instance was found in a repackaged open source project, TabBarInteraction, but they’re just innocent victims. It was simple enough for someone to insert a script in the build process, and distribute the new, doped package. It’s probably not the only one out there, so watch out for Run Scripts with obfuscated payloads.

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USB Comes To The ESP32

March 26, 2021 by 20 Comments

Since the ESP8266 came on the scene a few years ago and revolutionized the way microcontrollers communicate with other devices, incremental progress on this chip has occurred at a relatively even pace. First there was the realization that code could be run on the chip itself. Next the ESP32 was released which built more on that foundation. The next step in that process of improvement may be here now as well, with this project which turns the ESP32 into a USB host.

USB is not a native feature on all microcontrollers or even Arduino-compatible boards. While some do have it built in like those based on the 32u4 for example, most either don’t have it at all or rely on a separate on-board chip to do some form of translating. The ESP32 is lacking this advanced feature so the USB needs to be cobbled together from scratch if you want this specific board to be able to interface directly with peripherals. This project does just that, allowing for four USB 1.1 devices to be connected directly to the ESP32 without a separate dedicated chip.

If you’ve been waiting for USB on this tiny, capable microcontroller this might be your chance to try it out. All of the project’s code is available on the project page. And, while it is limited in scope, it’s easily able to handle a keyboard or mouse. This might be a more cost-effective way of doing something like a KVM switch rather than doing it with three Arduinos.