Virtual Reality With A Dash Of Live Shakespeare

March 27, 2021 by 5 Comments

Virtual reality headsets enforce an isolated experience, cutting us off from people nearby when we put one on our head. But in recent times, when we’re not suppose to have many people nearby anyway, a curious reversal happens: VR can give us a pandemic-safe social experience. Like going to our local community theater, which is an idea [Tender Claws] has been exploring with The Under Presents.

VR hype has drastically cooled, to put it mildly. While some believe the technology is dead and buried, others believe it is merely in a long tough climb out of the Trough of Disillusionment. It is a time for innovators to work without the limelight of unrealistic expectations. What they need is a platform for experiments, evaluate feedback, and iterate. A cycle hackers know well! The Under Presents is such a platform for its corner of VR evolution.

Most VR titles are videogames of one genre or another, so newcomers to the single-player experience may decide its otherworldly exploration feels like Myst. A multi-player option is hardly novel in this day and age, but the relatively scarcity of VR headsets means this world is never going to be as crowded as World of WarCraft. This is not a bug, it is a differentiating feature. Performers occasionally step into this world, changing the experience in ways no NPC ever could. A less crowded world makes these encounters more frequent, and more personal.

Pushing this idea further, there have been scheduled shows where a small audience is led by an actor through a story. As of this writing, a run of a show inspired by Shakespeare’s Tempest is nearing its end. The experience of watching an actor adjusting and reacting to an audience used to be exclusive to an intimate theater production. But with such venues closed, it is now brought to you by VR.

How will these explorations feature in the future of the technology? It’s far too early to say, but every show moves VR storytelling a little bit forward. We hope this group or another will find their way to success and prove the naysayers wrong. But it is also possible this will all go the way of phone VR. We are usually more focused on the technical evolution of VR here, but it’s nice to know people are exploring novel applications of the technology. For one can’t exist for long without the other.

Raspberry Pi Zero Beams Back Video From 100,000 Feet

March 26, 2021 by 13 Comments

The Project Horus team routinely launches high-altitude balloons in Australia. However, despite their desire for it, they haven’t beamed back live video. Until now. Horus 55 beamed video back to the ground from over 100,000 feet using a Raspberry Pi and some software-defined radio gear. Be sure and check out their video, below.

You might think this is easy, but there are many technical hurdles. First, the transmitter needs some power, but the thin atmosphere creates problems with cooling. In addition a really good receiving station is required, and the project wanted to stream that video to the Internet, which they were able to do.

The balloon carried a Raspberry Pi Zero W to capture and compress video. A LimeSDR Mini provided the DVB-S transmission on 70cm along with a power amplifier to get to about 800mW. Power dissipation in the payload was about 6 watts and required a special heat sink system to operate. The payload was powered by eight lithium AA primary cells, which perform well at low temperatures.

Continue reading “Raspberry Pi Zero Beams Back Video From 100,000 Feet” →

Move Over Cesium Clock, Optical Clocks Are Taking Over

March 26, 2021 by 26 Comments

We normally think of atomic clocks as the gold standard in timekeeping. The very definition of a second — in modern times, at least — is 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of a stationary cesium-133 atom at a temperature of 0K. But there is a move to replace that definition using optical clocks that are 100 times more accurate than a standard atomic clock.

In recent news, the Boulder Atomic Clock Optical Network — otherwise known as BACON — compared times from three optical clocks and found that the times differed a little more than they had predicted, but the clocks were still amazingly accurate relative to each other. Some of the links used optical fibers, a method used before. But there were also links carried by lasers aimed from one facility to another. The lasers, however didn’t work during a snowstorm, but when they did work the results were comparable to the optical fiber method.

Continue reading “Move Over Cesium Clock, Optical Clocks Are Taking Over” →

Skid Steer Robot Chassis Takes A Beating

March 26, 2021 by 5 Comments

[Engineering After Hours] wanted a highly maneuverable robot chassis with a tight turning radius. Skid steering seemed to be the perfect solution, but the available commercial options didn’t take his fancy. Thus, a custom build was the answer – with impressive results.

The build packs two large RC motors, one for each side, with each driving two wheels through a belt drive. This reduces the electronics required to the bare minimum for skid steering. It’s all assembled within a plasma-cut metal chassis which is more than tough enough to take some hard knocks.

One of the primary goals on the build was to eliminate the risk of vibrations and shock damaging the motors and gearboxes. Many off-the-shelf designs couple the wheels directly to gearbox output shafts, potentially damaging the expensive components over time. In this design, a separate bearing assembly is used to take the load from the wheels instead.

It’s a great example of how an engineering-first approach can build a sturdy ‘bot with a minimum of fuss. Outfitted with some fat off-road tyres the performance is impressive, with the ‘bot having no trouble tearing it up in mud, snow, and water.

We’ve seen other great builds from [Engineering After Hours] before, like the active aero RC build. Video after the break.

Continue reading “Skid Steer Robot Chassis Takes A Beating” →

Nixie Shot Timer Adds Useful Elegance To Espresso Machine

March 26, 2021 by 11 Comments

Once you’ve ground the beans and tamped the grounds just so, pulling the perfect shot of espresso comes down to timing. Ideally, the extraction should last 20-30 seconds, from the first dark drips to the tan and tiger-striped crema on top that gives the espresso a full aftertaste.

[Marco] has a beautiful espresso machine that was only missing one thing: an equally beautiful shot timer with a Nixie tube display. Instead of messing with the wiring, [Marco] took the non-invasive approach and is using a DIY coil to detect the magnetic field of the espresso machine’s pump and start a shot timer.

An LM358-based op-amp magnifies the current induced by the machine and feeds it to an Arduino Nano, which does FFT calculations. [Marco] found a high-voltage interface driver to switch 170 V to the Nixies instead of using two handfuls of transistors. Grab yourself a flat white and check it out after the break.

The last Nixies may have been mass-produced in the 1980s, but never fear — Dalibor Farny is out there keeping the dream alive and making new Nixies.

Continue reading “Nixie Shot Timer Adds Useful Elegance To Espresso Machine” →

Real Time Object Detection For $59

March 26, 2021 by 19 Comments

There was a time when making a machine to identify objects in a camera was difficult, even without trying to do it in real time. But now, you can do it with a Jetson Nano board for under $60. How well does it work? Watch [Murtaza’s] video below and see what you think.

The first few minutes of the video piqued our interest, and good thing, too, because the 50 lines of code get a 50-plus minute video! It is worth watching, though, because there’s a lot of good information about how to apply this technique in your own projects.

Continue reading “Real Time Object Detection For $59” →

Bare-Metal STM32: Please Mind The Interrupt Event

March 26, 2021 by 27 Comments

Interruptions aren’t just a staple of our daily lives. They’re also crucial for making computer systems work as well as they do, as they allow for a system to immediately respond to an event. While on desktop computers these interrupts are less prominent than back when we still had to manually set the IRQ for a new piece of hardware using toggle switches on an ISA card, IRQs along with DMA (direct memory access) transfers are still what makes a system appear zippy to a user if used properly.

On microcontroller systems like the STM32, interrupts are even more important, as this is what allows an MCU to respond in hard real-time to an (external) event. Especially in something like an industrial process or in a modern car, there are many events that simply cannot be processed whenever the processor gets around to polling a register. Beyond this, interrupts along with interrupt handlers provide for a convenient way to respond to both external and internal events.

In this article we will take a look at what it takes to set up interrupt handlers on GPIO inputs, using a practical example involving a rotary incremental encoder.

Continue reading “Bare-Metal STM32: Please Mind The Interrupt Event” →