Day: March 16, 2021

Design Solutions For The Heat Crisis In Cities Around The World

March 16, 2021 by 75 Comments

It was 1999 when Smash Mouth dropped the smash hit All Star, stating “The ice we skate is getting pretty thin, the water’s getting warm so you might as well swim.” Since then, global temperatures have continued to rise, with no end in sight. Political will has been unable to make any grand changes, and the world remains on track to blow through the suggested hard limits set by scientists.

As a result, heatwaves have become more frequent, and of greater intensity, putting many vulnerable people at risk and causing thousands of deaths each year. This problem is worse in cities, where buildings and roads absorb more heat from the sun than natural landscapes do. This is referred to as the heat island effect, with cities often being several degrees warmer than surrounding natural areas. It’s significant enough that experts are worried some cities could become uninhabitable within decades. Obviously, that’s highly inconvenient for those currently living in said cities. How bad is the problem, and what can be done?

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Jet Powered Go Kart Built With RC Gear

March 16, 2021 by 16 Comments

Turbine cars never quite came to be, despite many experiments in the 20th century. Despite their high power output for their size, they’re just not well suited to land transport applications; even the M1A1 tank has been much maligned for its turbine power plant. That didn’t stop [Warped Perception] for throwing a jet on the back of a kart though, and it looks like a whole lot of fun. (Video, embedded below.)

The build starts with a garden variety gokart, with the piston engine and all associated running gear stripped off in haste. The RC-sized turbo jet is then mounted on an elegant aluminium bracket, neatly welded on to the back of the car. It’s hooked up with its electronic controller, with throttle controlled by an RC transmitter. It’s not ideal trying to steer one-handed with another on the stick, but these are the sacrifices made when parts don’t arrive in time.

Early testing revealed issues with air ingestion into the fuel line over bumps, but overall performance was impressive. Future plans involve a top speed run which we can’t wait to see. Of course, if it’s not outrageous enough for your taste, consider [Colin Furze’s] pulsejet build.

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The Raspberry Pi Pico As An SDR Receiver

March 16, 2021 by 30 Comments

With the profusion of cheap RTL-SDR devices and the ever-reducing prices of more capable SDRs there might seem to be little place left for the low-bandwidth devices we’d have been happy with a decade or more ago, but there’s still plenty to be learned from something so simple. It’s something [Luigi Cruz] shows us with a simple SDR using the analogue-to-digital capabilities of the Raspberry Pi Pico, and since it works with GNU Radio we think it’s rather a neat project. CNX Software have the full story, and and quickly reveal that with its 500k samples per second bandwidth it’s not a machine that will set the SDR world on fire even when pushing Nyquist’s Law to the limit.

So with the exception of time signals and a few Long Wave broadcast stations if you live somewhere that still has them, you’ll need a fliter and receive converter to pull in anything of much use radio-wise with this SDR. But a baseband SDR with a couple of hundred kHz useful bandwidth and easy hackability through GNU Radio for the trifling cost of a Raspberry Pi Pico has to be worth a second look. You can see it in action in the video below the break, and if you’re at a loss for what to do with it take a look at Michael Ossmann and Kate Temkin’s 2019 Superconference talk.

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