The sensor hub in all its glory, sensor itself on top, standing on 3D-printed feet, and the PCB on the bottom

Hacker-Friendly And Elegant Air Quality Sensor Hub

Ever wanted an indoor environment sensor that’s dead simple yet a complete package? That’s the anotter-sensor-hub project from [Jana Marie], designed for the Sensirion SEN05x series sensors, with a SEN055 sensor shown in the picture above. Given such a sensor, you can measure VOCs and NOCs (Volatile and Non-Volatile Organic Compounds), as well as PM1, PM2.5, PM4 and PM10 particulate matter indices, with temperature and humidity sensing thrown in for good measure. Fully open and coupled with 3D printable stand files, this alone makes for an air quality hub fit for a hacker’s desk. That’s not all, however — this board’s elegant extensibility is a good match for the sensor’s impressive capabilities!

The PCB itself might look simple, it’s simply an ESP32 and some supporting circuitry required. But you’ll notice there’s also a trove of connector footprints for different interfaces; whatever else you might want to add to your sensor hub, whether it connects through I2C, SPI or PWM, you can! As usual, the sensor itself is the most expensive part of such a project — the boards themselves are around $5 USD apiece fully assembled, but one sensor-included hub will set you back roughly $42 USD. That said, it’s a great value for the price, and the trove of sensing data you can get might just more than pay for itself in quality-of-life improvements you make. Of course, everything is open-source and comes as a complete packages for you to start using. The firmware, KiCad files, 3D holder and even Grafana dashboard files can be found on GitHub.

Such air quality sensor platforms have been getting more and more popular, and hackers have been paying attention. Having a full open-source package like this at our disposal is amazing. If you’re looking for a cheaper “baby’s first air quality sensor”, drop by your local IKEA — there’s a way less featureful but quite cheap sensor that you can equip with an ESP8266, perhaps, even on a custom PCB.

A Milliwatt Of DOOM

The seminal 1993 first-person shooter from id Software, DOOM, has become well-known as a test of small computer platforms. We’ve seen it on embedded systems far and wide, but we doubt we’ve ever seen it consume as little power as it does on a specialized neural network processor. The chip in question is a Syntiant NDP200, and it’s designed to be the always-on component listening for the wake word or other trigger in an AI-enabled IoT device.

DOOM running on as little as a milliwatt of power makes for an impressive PR stunt at a trade show, but perhaps more interesting is that the chip isn’t simply running the game, it’s also playing it. As a neural network processor it contains the required smarts to learn how to play the game, and in the simple circular level it’s soon picking off the targets with ease.

We’ve not seen any projects using these chips as yet, which is hardly surprising given their niche marketplace. It is however worth noting that there is a development board for the lower-range sibling chip NDP101, which sells for around $35 USD. Super-low-power AI is within reach.

A person holds a bundle of white, black, and blue wires. The left hand side of the wires are wrapped with black tape. The wires are inside a wire wrapping machine with a grey plastic "C" which rotates inside seven small pulleys. A large pulley in the background drives three of the pulleys to rotate the "C" around and wrap the wires with tape from the spool attached to the "C."

DIY Tool Makes Wrapping Wiring Harnesses A Breeze

If you’re making a lot of wiring harnesses, wrapping them can become a bit of a drag. [Well Done Tips] wanted to make this process easier and built a wiring harness wrapping machine.

The “C” shape of this wrapping machine means that you can wrap wires that are still attached at one or both ends, as you don’t have to pull the wires all the way through the machine. The plastic “C” rotates inside a series of pulleys with three of them driven by a belt attached to an electric motor. A foot pedal actuates the motor and speed is controlled by a rotary dial on the motor controller board.

Since this is battery powered, you could wrap wires virtually anywhere without needing to be near a wall outlet. This little machine seems like it would be really great if you need to wrap a ton of wire and shouldn’t be too complicated to build. Those are some of our favorite hacks.

If you’re wanting more wire harness fun, try this simple online wiring harness tool or see how the automotive industry handles harnesses.

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Hackaday Links: February 26, 2023

It’s probably safe to say that most of us have had enough of the Great Balloon Follies to last the rest of 2023 and well beyond. It’s been a week or two since anything untoward was spotted over the US and subsequently blasted into shrapnel, at least that we know of, so we can probably put this whole thing behind us.

But as a parting gift, we present what has to be the best selfie of the year — a photo by the pilot of a U-2 spy plane of the balloon that started it all. Assuming no manipulation or trickery, the photo is remarkable; not only does it capture the U-2 pilot doing a high-altitude flyby of the balloon, but it shows the shadow cast by the spy plane on the surface of the balloon.

The photo also illustrates the enormity of this thing; someone with better math skills than us could probably figure out the exact size of the balloon from the apparent size of the U-2 shadow, in fact.

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Rubber Bands And O-Rings Give 3D Prints Some Stretch

Sometimes it would be helpful if a 3D printed object could stretch & bend. Flexible filament like TPU is one option, but [NagyBig] designed a simple bracelet to ask: how about embedding rubber bands or o-rings into the print itself?

Embedding objects into prints usually involves hardware like fasteners or magnets, but this is the first one (we can think of) that uses rubber bands. Though we have seen rubber bracelets running on printed wheels, and o-rings used to provide tension on a tool holder.

The end result is slightly reminiscent of embedding 3D printed shapes into tulle in order to create fantastic, armor-like flexible creations. But using rubber bands means the result is stretchy and compliant to a degree we haven’t previously seen. Keep it in mind the next time you’re trying to solve a tricky design problem; an embedded o-ring or rubber band might just do the trick.

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A Loving Look Inside Vacuum Fluorescent Displays

Everyone knows we’re big fans of displays that differ from the plain old flat-panel LCDs that seem to adorn most devices these days. It’s a bit boring when the front panel of your widget is the same thing you stare at hour after hour while using your phone. Give us the chunky, blocky goodness of a vacuum fluorescent display (VFD) any day of the week for visual interest and retro appeal.

From the video below, it seems like [Posy] certainly is in the VFD fandom too, rolling out as he does example after example of unique and complicated displays, mostly from audio equipment that had its heyday in the 1990s. In some ways, the video is just a love letter to the VFD, and that’s just fine with us. But the teardowns do provide some insights into how VFDs work, as well as suggest ways to tweak the overall look of a VFD.

For example, consider the classy white VFDs that graced a lot of home audio gear back in the day. It turns out, the phosphors used in those displays weren’t white, but closer to the blue-green color that VFDs are often associated with. But put a pink filter between the display and the world, and suddenly those turquoise phosphors look white. [Posy] does a lot of fiddling with the stock filters to change the look of his VFDs, some to good effect, others less so.

As for the internals of VFDs, [Posy]’s look at a damaged display reveals a lot about how they work. With a loose scrap of conductor shorting one of the cathodes inside the tube, the damaged VFD isn’t much to look at, and is beyond reasonable repair, but it’s kind of cool to examine the spring mechanisms that take up slack as the cathodes heat up and expand.

Thanks to [Posy] for this heartfelt look into the VFDs of yesterday. If you need more about how VFDs work, we’ve covered that before, too.

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The Last Meccano Factory Is To Close. Will We Miss It?

If we were to talk to engineers about the childhood toys which most inspired them, it’s likely that the older among them would mention either Meccano or Erector Set. These similar construction toys using metal components originated independently around the turn of the 20th century in both Britain and America, and eventually became part of the same company.

They were a staple of toy shops through the middle of the century, but have steadily declined in popularity over the past few decades. Now news has emerged that the last dedicated Meccano factory, in Calais, France, is to close. The products will still be made, but in other factories alongside other toys. It’s not the end for Meccano or Erector Set, but it’s clear that they are both toys whose time may have passed.

It’s fair to say that the possibilities of those perforated metal sheets and myriad nuts and bolts might seem a little limited for the 2020s child, but it opens the age-old question of what remains to interest young minds in engineering or technology. The obvious answer to that question comes in the form of Lego, evidently so much more fun can be had with plastic bricks.

Did you have Meccano or Erector Set when you were a kid? If so what did you do with it? We’ve seen a few projects using it here over the years.

Header: Alf van Beem, CC0.