Atomic Antenna Uses Lasers

If you think about it, an antenna is nothing more than a radio frequency energy sensor, or — more precisely — a transducer. So, it shouldn’t be a surprise that there could be different ways to sense RF that would work as an antenna. A recent paper in Applied Physics Letters explains an atomic antenna comprised of a rubidium vapor cell.

The interesting thing is that the antenna has no electrical components in the antenna, and can be located far away from the actual receiver. Instead of coax cables, the signal is read with a laser.

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Bluetooth Device Visualizer Reveals Devices In Vicinity

Have you ever wondered how many Bluetooth devices are floating around you? You could use one of those creepy retail store Bluetooth tracking systems, or set your smartphone to scan. Alternatively, you could use the Bluetooth Devices Visualizer from [Jeremy Geppert].

The device was inspired by [Jeremy’s] trip to Hackaday Supercon 2022. Wanting to build something with LEDs that worked in a badge-like form factor, he set out on whipping up a device to scan and display a readout of Bluetooth devices in the immediate area.

The device is based on an ESP32 microcontroller, which provides the necessary Bluetooth hardware to scan for devices. It then displays the number of devices found using an 8 x 8 array of addressable LEDs. There is also a small OLED display on board for displaying relevant details to the device’s operation. The device neatly fits on a lanyard, and is more of an art project than anything else. It’s no wardriver, and details of devices found are not logged or stored in any way when the device is switched off.

With a variety of operational modes, it’s a fun way to get an idea of just how many Bluetooth devices are really out there these days. If you’ve got your own nifty Bluetooth hacks in the works, don’t hesitate to let us know!


PC Case Makes Portable Power Supply

Recently, we’ve seen a lot of semi-portable power stations. These have some big rechargeable battery and various connection options. [Dereksgc] wanted to make his own and decided the perfect housing would be a small PC tower case. (Video, embedded below.) It makes sense. There are plenty of easy-to-work front panel inserts, a power supply box with an AC cord (the power supply is long gone), and it is big enough to fit the battery. You can see the result in the video below.

The bulk of the work was installing power supply modules and a charge controller on floppy disk blank panels. The battery — a 50 Ah LiFePO4 unit — fits nicely in the bottom. Some of the buttons and connectors find use in the new incarnation.

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Building A Robot Bartender For Amazon

[Audax] built an unassuming side table with a party trick. It could retract a glass inside and fill it up with bourbon. The nifty device gained plenty of positive attention online, leading to a commission from Amazon to build a new version. Thus, [Audax] set about a redesign to create an even more impressive drink delivery system. (Video, embedded below.)

The story is very much one of refinement and optimization, focusing on the challenges of building a customer-facing device. With just six weeks to create the new rig, [Audax] had to figure out how to make the machine sleeker and more compact for its debut at a special event. To achieve this, he eschewed the original frame design made of aluminium extrusion, going for a 3D-printed design instead. The wire nest of the original version was then subsequently eliminated by an outsourced PCB design. Other new features included a mobile app for control and an easier way to adjust pour size, for bigger or smaller drinks as desired. For ease of use, activation is via an Amazon Alexa Skill.

As is so often the way, a last minute hurdle came up, prompting [Audax] to fly to Seattle to troubleshoot the rig on site. Nevertheless, the automatic drink server came good in the end, and delivered on its promise. Video after the break.

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Arduino-Controlled Coil Winder

Coil winders are a popular project because doing the deed manually can be an incredibly tedious and time consuming task. After building one such rig, [Pisces Printing] wanted to find even further time savings, and thus designed an improved, faster version.

At it’s heart, it’s a straightforward design, using a linear rail and a leadscrew driven by a stepper motor. Control is via an Arduino Nano, with a few push buttons and a 16 x 2 LCD display for user feedback.

Often, completing a first build will reveal all manner of limitations and drawbacks of a design. In this case, the original winder was improved upon with faster stepper motors to cut the time it took to wind a coil. A redesigned PCB also specified a better buck converter power supply to avoid overheating issues of the initial design. A three-jaw lathe-style chuck was also 3D printed for the build to allow easy fixing of a coil bobbin.

Designing custom tools can be highly satisfying in and of itself, beyond the productivity gains they offer. Video after the break.

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The Eternal Dilemma

It’s two weeks until Supercon! We can almost smell the solder from here. If you’re coming, and especially if it’s your first time, you’re soon to be faced with the eternal dilemma of hacker cons, only at Supercon it’s maybe a trilemma or even a quadralemma: hang out with folks, work on the badge, go to talks, or show off all the cool stuff you’ve been working on the past year?

Why not all four? That’s exactly why we start off with a chill-out day on Friday, when we don’t have much formally planned. Sure, there’s a party Friday night, and maybe a badge talk or some workshops, but honestly you’ll have most of the day free. Ease into it. Have a look at the badge and start brainstorming. Meet some new people and start up a team. Or just bathe in the tremendous geekery of it all. This is also a great time to show off a small project that you brought along. Having the widget that you poured brain, sweat, and tears into sitting on the table next to you is the perfect hacker icebreaker.

On Saturday and Sunday, there will definitely be talks that you’ll want to attend, so scope that out ahead of time and plan those in. But don’t feel like you have to go to all of them, either. Most of the talks will be online, either right away or eventually, so you won’t miss out forever. But since our speakers are putting their own work out there, if you’re interested in the subject, having questions or insight about their talk is a surefire way to strike up a good conversation later on, and that’s something you can’t do online. So plan in a few talks, too.

You’ll find that the time flies by, but don’t feel like you have to do it all either. Ask others what the coolest thing they’ve seen is. Sample as much as you can, but it’s not Pokemon – you can’t catch it all.

See you in two weeks!

(PS: The art is recycled from a Supercon long, long ago. I thought it was too nice to never see it again.)

CPU Cooler In A Printer’s Hot End

[Proper Printing] often does unusual 3D printer mods. This time, he’s taking a CPU cooler made for a Raspberry Pi with some heat pipes and converting it into a 3D printer hot end. Sound crazy? It is even crazier than it sounds, as seen in the video below.

Heat pipes contain a liquid and a wick, so bending them was tricky. It also limited the size of the heat break he could use since the two heat pipers were relatively closely spaced. Once you have the cooler reshaped and a threaded hole for the heatbreak, the rest is anticlimactic. The heatbreak holds a heat block that contains the heating element and temperature sensor. A few changes were needed to the custom extruder cut out of acrylic, but that didn’t have anything to do with the fan and mount.

Normally, a hot end assembly has a substantial heat sink, and a fan blows air over it. The heat pipe technique is a common way to move heat away from a tight space. So, the way it is used here is probably not very useful compared to a conventional technique. However, we can imagine tight designs where this would be viable.

Heat pipes aren’t the same as water cooling, even though some use water inside. A heat pipe is a closed system. The fluid boils off at the hot end, condenses at the cool end, and wicks the liquid back to close the cycle. On the other hand, you can use more conventional water cooling, too.

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