Building An IR Thermometer That Fits On Your Keychain

Non-contact infrared (IR) thermometers used to be something of an exotic tool, but thanks at least in part due to the COVID-19 pandemic, they’re now the sort of thing you see hanging up near the grocery store checkout as a cheap impulse buy. Demand pushed up production, and the economies of scale did the test. Now the devices, and the sensors within them, are cheap enough for us hackers to play with.

The end result is that we now have projects like this ultra compact IR thermometer from [gokux]. With just a handful of components, some code to glue it all together, and a 3D printed enclosure to wrap it all up, you’ve got a legitimately useful tool that’s small enough to replace that lucky rabbit’s foot you’ve got on your keys.

If this project looks familiar, it’s because the whole thing is closely related to the LiDAR rangefinder [gokux] put together last month. It shares the same Seeed Studio XIAO  ESP32-C3 microcontroller, 0.49 inch OLED display, and tiny 40 mAh LiPo battery. The only thing that’s really changed, aside from the adjustments necessary to the 3D printed enclosure, is that the LiDAR sensor was replaced with a MLX90614 IR temperature sensor.

[gokux] has put together some great documentation for this build, making it easy for others to recreate and remix on their own. Assembly is particularly straightforward thanks to the fact that both the display and temperature sensor communicate with the ESP32 over I2C, allowing them to be wired daisy chain style — there’s no need for even a scrap of perfboard inside the case, let alone a custom board.

Dad? Where Did Printed Circuit Boards Come From?

These days, it is hard to imagine electronics without printed circuit boards. They are literally in everything. While making PCBs at home used to be a chore, these days, you design on a computer, click a button, and they show up in the mail. But if you go back far enough, there were no PC boards. Where did they come from? That’s the question posed by [Steven Leibson] who did some investigating into the topic.

There were many false starts at building things like PCBs using wires glued to substrates or conductive inks.  However, it wasn’t until World War II that mass production of PC boards became common. In particular, they were the perfect solution for proximity fuzes in artillery shells.

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The Thermite Process Iron Foundry

The thermite process is a handy way to generate molten iron in the field. It’s the reaction between aluminium metal and iron oxide, which results in aluminium oxide and metallic iron. It’s hot enough that the iron is produced as a liquid, which means it’s most notably used for in-field welding of things such as railway tracks. All this is grist to [Cody’s Lab]’s mill of course, so in the video below the break he attempts to use a thermite reaction in a rough-and-ready foundry, to make a cast-iron frying pan.

Most of the video deals with the construction of the reaction vessel and the mold, for which he makes his own sodium silicate and cures it with carbon dioxide. The thermite mix itself comes from aluminium foil and black iron oxide sand, plus some crushed up drinks cans for good measure.

The result is pretty successful at making a respectable quantity of iron, and his pour goes well enough to make a recognizable frying pan. It has a few bubbles and a slight leak, but it’s good enough to cook an egg. We’re sure his next try will be better. Meanwhile this may produce a purer result, but it’s by no means the only way to produce molten iron on a small scale.

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A Look Back At The USSR’s Mi-6 Helicopter Airliner

Most of us would equate commercial airline travel with fixed-wing aircraft, but civilian transport by helicopter, especially in large and sparsely populated regions, is common enough. It was once even big business in the Soviet Union, where the Aeroflot airline operated passenger helicopters in regular service for many decades. In the mid-1960s they even started work on converting the Mil Mi-6 — the USSR’s largest and fastest helicopter — to carry paying passengers. Unfortunately this never got past a single prototype, with the circumstances described by [Oliver Parken] in a recent article.

This passenger version of the Mi-6 got the designation Mi-6P (for passazhirskyi, meaning passenger) and would have seated up to 80 (3 + 2 row configuration), compared to the Mi-8 passenger variant that carried 28 – 31 passengers. Why exactly the Mi-6P never got past the prototype stage is unknown, but its successor in the form of the Mi-26P has a listed passenger variant and features. Both have a cruising speed of around 250 km/h, with a top of 300 km/h. The auxiliary winglets of the Mi-6 provided additional lift during flight, and the weight lifting record set by the Mi-6 was only broken by the Mi-26 in 1982.

An obvious disadvantage of passenger helicopters is that they are more complicated to operate and maintain, while small fixed wing airliners like the ATR 72 (introduced in 1988) can carry about as many passengers, requires just a strip of tarmac to land and take off from, travel about twice as fast as an Mi-6P would, and do not require two helicopter pilots to fly them. Unless the ability to hover and land or take-off vertically are required, this pretty much explains why passenger helicopters are such a niche application. Not that the Mi-6P doesn’t have that certain je ne sais quoi to it, mind.

Hacking A Quansheng Handheld To Transmit Digital Modes

Have you ever thought about getting into digital modes on the ham bands? As it turns out, you can get involved using the affordable and popular Quansheng UV-K6 — if you’re game to modify it, that is. It’s perfectly achievable using the custom Mobilinkd firmware, the brainchild of one [Rob Riggs].

In order to efficiently transmit digital modes, it’s necessary to make some hardware changes as well. Low frequencies must be allowed to pass in through the MIC input, and to pass out through the audio output. These are normally filtered out for efficient transmission of speech, but these filters mess up digital transmissions something fierce.  This is achieved by messing about with some capacitors and bodge wires. Then, one can flash the firmware using a programming cable.

With the mods achieved, the UV-K6 can be used for transmitting in various digital modes, like M17 4-FSK. The firmware has several benefits, not least of which is cutting turnaround time. This is the time the radio takes to switch between transmitting and receiving, and slashing it is a big boost for achieving efficient digital communication. While the stock firmware has an excruciating slow turnaround of 378 ms, the Mobilinkd firmware takes just 79 ms.

Further gains may be possible in future, too. Bypassing the audio amplifier could be particularly fruitful, as it’s largely in the way of the digital signal stream.

Quansheng’s radios are popular targets for modification, and are well documented at this point.

Hackaday Podcast Episode 278: DIY Subs, The ErgoRing, And Finding NEMA 17

In this episode, Hackaday Editors Elliot Williams and Tom Nardi kick things off with a reminder about the impending deadline for Supercon talk and workshop proposals. From there discussion moves on to the absolutely incredible tale of two brothers who solved a pair of missing person cases with their homebrew underwater vehicle, false data sneaking into OctoPrint’s usage statics, and an organic input device that could give the classic mouse a run for its money.

You’ll also hear about cheap radar modules, open source Xbox mod chips, and lawnmowers from the grocery store. The episode wraps up with a look at the enduring mystique of perpetual motion devices, and the story of a legendary ship that might soon end up being turned into paper clips.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

As always, this week’s episode is available as a DRM-free MP3.

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Build A DIY Spinner To Get Your Tempest Game Going

These days, controls in games are fairly standardized by genre. Most RTSs, FPSs, and RPGs all control more or less the same way. But one type of controller that has fallen by the wayside is the paddle, or spinner. [jesster88] is a big Tempest fan, however, and a spinner is crucial. Thus, what else is there to do but whip up one’s own?

Tempest is one of the more difficult classic games to categorize.

The build is based around a wired optical mouse. It’s pulled apart, with its main PCB installed into a 3D printed enclosure. Inside, the optical sensor is pointed at the base of a spinner constructed out of a printed drum and an off-the-shelf knob. The spinner is installed in a skateboard-style bearing for smooth rotation. As it spins, the optical sensor detects the motion and reports it as mouse movement via USB.

[jesster88] uses the device for playing Tempest with MAME. We imagine the technique could be adapted to work with other games that rely on spinner or paddle inputs, too. Meanwhile, if you’re whipping up your own retro game hacks at home, don’t hesitate to let us know!