SHOUT For Smaller QR Codes

QR codes have been with us for a long time now, and after passing through their Gardenesque hype cycle of inappropriate usage, have now settled down to be an important and ubiquitous part of life. If you have ever made a QR code you’ll know all about trying to generate the most compact and easily-scannable one you can, and for that [Terence Eden] is here with an interesting quirk. Upper-case text produces smaller codes than lower-case.

His post takes us on a journey into the encoding of QR codes, not in terms of their optical pattern generation, but instead the bit stream they contain. There are different modes to denote different types of payload, and in his two examples of the same URL in upper- and lower- cases, the modes are different. Upper-case is encoded as alphanumeric, while lower-case, seemingly though also containing alphanumeric information, is encoded as bytes.

To understand why, it’s necessary to consider the QR codes’ need for efficiency, which led its designers to reduce their character set as far as possible and only define uppercase letters in their alphanumeric set. The upper-case payload is thus encoded using less bits per character than the lower-case one, which is encoded as 8-bit bytes. A satisfying explanation for a puzzle in plain sight.

Hungry for more QR hackery? This one contains more than one payload!

An overhead shot of a parking lot. A road with cars parked along it is on the right hand side of the image. The top center shows a drilling rig on tracks drilling at a slight angle into the ground. Many different semi trailers dot the parking along with several different pallets of construction supplies. An excavator and skylift/forklift are also at work in the lot.

District Heat Pump Systems Save Money And Gas Utilities

Ground-source heat pump systems are one of the most efficient ways to do climate control, but digging the wells can be prohibitively expensive for the individual citizen. What if you could do it at a larger scale?

Starting with a pilot to serve 37 commercial and residential buildings in Framingham, MA, Eversource is using its experience with natural gas drilling and pipe to serve up a lower carbon way to heat and cool this neighborhood. While district heating via geothermal has precedents elsewhere in the country, Boise is a notable example, it has remained a somewhat niche technology. Once networked, excess heat from one location can be used elsewhere in the system, like data centers or industrial facilities being used to heat homes in the winter.

As gas utilities look to transition away from fossil fuels, their existing knowledge base is a perfect fit for geothermal, but there are some regulatory hurdles. Six states have passed laws allowing natural gas utilities to expand beyond just gas, and bills have been filed in six more. This will likely accelerate with the formation of the Utility Networked Geothermal Collaborative which includes many utilities including giants like Dominion Energy who are looking to expand their energy portfolios.

If you want to dig more into district heating systems or geothermal energy, we’ve covered cogeneration from power plants to serve up the heat instead, doing it with wind, or even using old coal mines for geothermal heat.

Building A DIY Muon Tomography Device For About $100

Muon tomography, or muography, is the practice of using muons generated by cosmic rays interacting with Earth’s atmosphere to image structures on Earth’s surface, akin to producing an X-ray. In lieu of spending a fair bit of money on dedicated muon detectors, you can also hack such a device together with two Geiger-Müller tubes and related circuitry for about $100 or whatever you can source the components for.

The reason for having two Geiger-Müller tubes is to filter out other much more prevalent sources of ionizing radiation that we’re practically bathed in every second. Helped by a sheet of lead between both tubes, only a signal occurring at the same time from both tubes should be a muon. Specially cosmic ray muons, as these have significantly more kinetic energy that allows them to pass through both tubes. As a simple check it’s helpful to know that most of these muons will come from the direction of the sky.

The author of the article tested this cobbled-together detector in an old gold mine. Once there the presence of more rock, and fewer muons, was easily detected, as well as a surge in muons indicating a nearby void from a mine shaft. While not a fast or super-easy way to image structures, it’s hard to beat for the price and the hours of fun you can have while spelunking.

A bright yellow crew cab pickup is on an unpaved area with snow-capped mountains in the distance. In its bed is a matching camper shell which is somewhat trapezoidal with a smaller semicircular section that can pull out to lengthen the sleeping space of the camper. At the top of the image it says, "Sleeps Two!" with an arrow pointing to the camper shell.

Want A Truck With A Short Bed And A Long Camper Shell?

Camper shells are a time-honored piece of truck gear, but with modern trucks having increasingly vestigial beds, the length of your overnight abode has increasingly shrunk as well. To combat this problem, [Ed’s Garage] built a camper shell that extends once you’ve arrived at your campsite.

[Ed] wanted to keep things relatively low profile while still tall enough to sit up in for convenience, leading to a small bit of the shell peeking over the truck’s roof. To keep the cold Canadian winter out, attention was paid to proper weather sealing around the sliding portion of the shell so that it stays warm and dry inside.

While this would work on any truck, the mains power plugs in the bed of some modern trucks mean that certain glamping conveniences like a heater and projector can be easily powered while you’re in camp. We get to see the camper shell in action at the end of the video where the pros and cons of having your sleeping space also being your storage while en route become apparent.

If you’re looking for something a little less conventional for your camping experience, how about this solar camper or this retro bike camper?

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Too Smooth: Football And The “KnuckleBall” Problem

Picture a football (soccer ball) in your head and you probably see the cartoon ideal—a roughly spherical shape made with polygonal patches that are sewn together, usually in a familiar pattern of black and white. A great many balls were made along these lines for a great many decades.

Eventually, though, technology moved on. Footballs got rounder, smoother, and more colorful. This was seen as a good thing, with each new international competition bringing shiny new designs with ever-greater performance. That was, until things went too far, and the new balls changed the game. Thus was borne the “knuckleball” phenomenon.

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A dark warehouse contains a number of large blocky objects. A Tesla Model 3 sedan sits in the center with flames underneath and curling up the side away from the camera. A firefighter on the left side attempts to put out the fire with a fire hose.

UL Investigates The Best Way To Fight EV Fires

While electric vehicles (EVs) are generally less likely to catch fire than their internal combustion counterparts, it does still happen, and firefighters need to be ready. Accordingly, the UL Research Institute is working with reverse engineering experts Munro & Associates to characterize EV fires and find the best way to fight them.

There is currently some debate in the firefighting community over whether it’s better to try to put an EV battery fire out with water or to just let it burn. Research like this means the decision doesn’t have to fall on only anecdotal evidence. Anyone who’s worked in a lab will recognize the mix of exceedingly expensive equipment next to the borderline sketchy rigged up hacks on display, in this case the super nice thermal imagers and a “turkey burner on steroids.” The video goes through some discussion of the previous results with a Chevy Bolt, Hyundai Kona, Ford Mustang Mach E, and then we get to see them light up a Tesla Model 3. This is definitely one you shouldn’t try at home!

While the massive battery banks in modern EVs can pose unique challenges in the event of an accident, that doesn’t mean they can’t be repurposed to backup your own home.

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