Hedgehog Gesture Sensor Built With Cheap Time-of-Flight Modules

November 2, 2021 by Lewin Day 6 Comments

Time-of-flight sensors used to be expensive obscurities, capable of measuring the travel time of photons themselves and often used for tracking purposes. However, the technology is cheaper now, such that [jean.perardel] has used TOF sensors to build a useful and affordable gesture-tracking system.

The system relies on four VL53L1X time of flight sensors, which have a 16×16 scanning array and communicate over the I2C bus. Controlling the show is an Arduino MKR1010, though the project should be achievable with a range of other microcontrollers, too.

The device is built into a cute hedgehog-like form factor, with an LCD screen acting as the face. It displays facial expressions which show how the system is interpreting and responding to gestures. It gives the project lots of personality, which makes using the system more fun. Gestures from the system can be used to send keystrokes over USB, control relays or servos, or even fire IR signals to control TVs and other hardware.

It actually seems like a useful gesture control interface, one that could become a useful part of a workstation setup. We’ve seen gesture controls put to other uses too, like controlling robot arms. Video after the break.

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Tech In Plain Sight: Air Conditioning

October 27, 2021 by Al Williams 41 Comments

I’m always amazed that technology can totally wipe out industries. Sure, some people make a living making horseshoes, for example, but the demand for them is way down compared to what it would have been when horses were the normal mode of transportation. But even so, people still make horseshoes. But think about the ice harvesting business. Never heard of it? Turns out, before refrigeration, there was a huge business of moving ice from where it naturally occurred to other places and storing it, usually underground with a lot of insulation. As far as I know, that business — including the neighborhood ice man — is totally gone now except for some historical exhibitions. We take refrigeration and air conditioning for granted, but it hasn’t been that long ago that ice was a luxury and your own reprieve from the heat was a fan.

Early Cooling

The story starts a little earlier than you might expect. In the 1840s, physician John Gorrie was concerned about “the evils of high temperature.” His hospital in Florida imported ice using the aforementioned ice trade and it wasn’t cheap nor was it very effective.

Undeterred, he developed a machine that used a horse, a waterwheel, steam, or wind power to drive a compressor to create ice. He got a patent in 1851 but it failed to catch on before his financial backer died. In fact, Oliver Evans had the idea in 1805 but never built a working machine. Jacob Perkins patented the first compression cooler in 1834, again with little practical use.

When U.S. President Garfield was shot, Navy engineers built a cooling box using cloths soaked in ice water to cool the president’s hospital room by 20 degrees. Since the mortally wounded president survived 80 days after the shooting, we presume he appreciated the comfort.

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Being Green, It’s A Rich Man’s Game

October 26, 2021 by Jenny List 245 Comments

It’s an old saying with an apocryphal origin: “May you live in interesting times“. We Brits are certainly living in interesting times at the moment, as a perfect storm of the pandemic, rising energy prices, global supply chain issues, and arguably the post-Brexit departure of EU-national truck drivers has given us shortages of everything from fresh vegetables in the supermarket to carbon dioxide for the food industry. Of particular concern is a shortage of automotive fuels at the filling station, and amid sometimes-aggressive queues for the pumps it’s reported that there’s a record uptick in Brits searching online for information about electric cars.

Nothing Like A Crisis To Make You Green

My VW Polo loaded for EMF 2018 — How I miss my little car, here loaded for EMF 2018.

This sudden interest in lower-carbon motoring may be driven by the queues rather than a concern for the planet, but it’s certainly true that as a culture we should be making this move if we are to have a hope of reducing our CO2 production and meeting our climate goals. A whole slew of lifestyle changes will have to be made over the coming years of which our car choices are only a part. Back to those beleaguered Brits again, a series of environmental protests have caused major disruption on the motorway network round London, not protesting against the traffic but campaigning for better home insulation.

For reasons of personal circumstance rather than principle, earlier this year I gave my trusty VW Polo to an old-Volks-nut friend and now rely on a bicycle. Living where I do within reach of everything I need it hasn’t been as challenging as I expected it to be, and aside from saving a bit of cash I know my general fitness level has gone up. Though I have less need for a car now than I used to, I intend to find myself another vehicle in due course so that I can do silly things such as throwing a Hackaday village in the back and driving halfway across Europe to a hacker camp. With an awareness that whatever I choose should be as good for the planet as I can make it then, I’ve been cruising the used-car websites to see what I can find.

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The Longest Ever Flight Was Over 64 Days In A Cessna 172

October 25, 2021 by Lewin Day 69 Comments

Often, when we think of long-endurance flights, our first thoughts jump to military operations. Big planes with highly-trained crew will fly for long periods, using air-to-air refuelling to stay aloft for extended periods.

However, many of the longest duration flights have been undertaken as entirely civilian operations. The longest of all happened to be undertaken by that most humble of aircraft, the Cessna 172. From December 1958 to February 1959, Bob Timm and John Cook set out to make history. The duo remained aloft for a full 64 days, 22 hours and 19 minutes, setting a record that stands to this day.

A Test of Endurance

One might expect that such an effort was undertaken to push the envelope or to strike new ground in the world of aerospace engineering. However, the real truth is that Bob Timm was a slot machine mechanic and former bomber pilot who worked at the Hacienda casino in Las Vegas. Proprietor Doc Bailey was always on the hunt for promotional ideas, and Timm pitched his boss that a record attempt in a plane bearing the casino’s branding would be a good way to go. Bailey agreed, and committed $100,000 to the effort.

Modifications to prepare the aircraft for the stunt took the best part of a year. The pint-sized Cessna was fitted with a 95-gallon belly tank, paired with a electric pump that could transfer fuel to the main wing tanks as needed. Special plumbing was also added that would allow the engine oil and filters to be changed while the engine was still running.

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Omni-Wheeled Cane Steers The Visually-Impaired Away From Obstacles

October 24, 2021 by Kristina Panos 21 Comments

Sure, there are smart canes out there, commercial and otherwise. We’ve seen more than a few over the years. But a group of students at Stanford University have managed to bring something novel to the augmented cane.

Theirs features a motorized omni wheel that sweeps smoothly from left to right during normal cane operation, and when the cane senses an object that turns out to be an obstacle, the omni wheel goes into active mode, pulling the user out of the path of danger.

Tied for best part of this build is the fact that they made the project with open hardware and published all the gory details in a repo, so anyone can replicate it for about $400.

The cane uses a Raspi 4 with camera to detect objects, and a 2-D LIDAR to measure the distance to those objects. There’s a GPS and a 9-DOF IMU to find the position and orientation of the user. Their paper is open, too, and it comes with a BOM and build instructions. Be sure to check it out in action after the break.

There’s more than one way to guide people around with haptic feedback. Here’s the smartest pair of shoes we’ve seen lately.

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Going Forward To The Land: Technology For Permaculture

October 21, 2021 by Jenny List 34 Comments

It’s usual for a Hackaday scribe to read hundreds of web pages over a typical week as we traverse the world in search of the good stuff to bring you. Sometimes they’re obvious Hackaday stories but as you’ll all no doubt understand we often end up on wild tangents learning about stuff we never expected to be excited about. Thus it was last week that I happened upon a GQ piece charting the dwindling remains of the communes set up in rural California by hippies during the counterculture years.

With only a few ageing residents who truly embraced the back-to-the-land dream remaining, these adventurously-designed home-made houses are gently decaying into the forest. It’s a disappearing world, but it’s also close to home for me as someone who crew up on a self-sufficiency smallholding in the 1970s. My parents may not have been hippies in the way those of everyone else in that scene at the time seemed to be, but I learned all my curiosity and hacking skills in the many opportunities presented to a small child by an unruly combination of small farm and metalworking business. There’s part of me that would build a hippy home in a Californian forest in a heartbeat, and throw myself with gusto into subsistence vegetable growing to get me through each winter.

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The Compute Module Comes Of Age: Say Hello To The Real Cutting Edge Of Raspberry Pi

October 14, 2021 by Jenny List 66 Comments

If we wanted to point to an epoch-making moment for our community, we’d take you back to February 29th, 2012. It was that day on which a small outfit in Cambridge put on the market the first batch of their new product. That outfit was what would become the Raspberry Pi Foundation, and the product was a run of 10,000 Chinese made versions of their very first single board computer, the Raspberry Pi Model B. With its BCM2835 SoC and 512 megabytes of memory it might not have been the first board that could run a Linux distribution from an SD card, but it was certainly the first that did so for pocket money prices. On that morning back in 2012 the unforseen demand for the new board brought down the websites of both the electronics distributors putting it on sale, and a now-legendary product was born. We’re now on version 4 of the Model B with specs upgraded in almost every sense, and something closer to the original can still be bought in the form of its svelte stablemate, the Pi Zero.

How Do You Evolve Without Casualties?

The original Pi Model B+ from 2014. The form factor has had a few minor changes, but hardware-wise the Pi 4 follows this pretty closely. Lucasbosch, CC BY-SA 3.0.

The problem with having spawned such a successful product line is this: with so many competitors and copies snapping at your heels, how do you improve upon it? It’s fair to say that sometimes its competitors have produced more capable hardware than the Pi of the moment, but they do so without the board from Cambridge’s ace in the hole: its uniquely well-supported Linux distribution, Raspberry Pi OS. It’s that combination of a powerful board and an operating system with the minimum of shocks and surprises that still makes the Pi the one to go for after all these years.

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