This Simple Media Player Will Inspire Beginners And Invite Experimentation

While it would have been considered science-fiction just a few decades ago, the ability to watch virtually any movie or TV show on a little slab that fits in your pocket is today no big deal. But for an electronics beginner, being able to put together a pocketable video player like this one would be quite exciting, and might even serve as a gateway into the larger world of electronics design.

For inspiration, [Alex] from Super Make Something on YouTube looked to the Rickrolling keychain media players we featured back in January. His player is quite a bit larger and more capable, with a PCB design that allows the player to be built in multiple configurations, from audio-only to full video and a LiPo battery. The guts of the player center around an ESP32 module, with an audio amp and speakers plus a 1.8″ LCD screen with SD card reader for storing media files. Add in a few controls and switches and a little code, and you’ll be playing back media files in a snap. Build info and demo in the video below.

It may be a simple design, but we feel like that’s the whole point. [Alex] has taken pains to make this as approachable a build as possible. All the parts are cheap and easily available, and the skills needed to put it together are minimal — with the possible exception of soldering down the ESP32 module, which lacks castellated edge terminals. For a beginner, getting a usable media player by mixing together just a few modules would be magical, and the fact that it’s still pretty hackable afterward is just icing on the cake.

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Dead Spider Becomes Robot Gripper: It’s Necrobotics!

Robot arms and grippers do important work every hour of every day. They’re used in production lines around the world, toiling virtually ceaselessly outside of their designated maintenance windows.

They’re typically built out of steel, and powered by brawny hydraulic systems. However, some scientists have gone for a smaller scale approach that may horrify the squeamish. They’ve figured out how to turn a dead spider into a useful robotic gripper.

The name of this new Frankensteinian field? Why, it’s necrobotics, of course!

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Inca Knots Inspire Quantum Computer

We think of data storage as a modern problem, but even ancient civilizations kept records. While much of the world used stone tablets or other media that didn’t survive the centuries, the Incas used something called quipu which encoded numeric data in strings using knots. Now the ancient system of recording numbers has inspired a new way to encode qubits in a quantum computer.

With quipu, knots in a string represent a number. By analogy, a conventional qubit would be as if you used a string to form a 0 or 1 shape on a tabletop. A breeze or other “noise” would easily disturb your equation. But knots stay tied even if you pick the strings up and move them around. The new qubits are the same, encoding data in the topology of the material.

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Berlin Clock Takes Inspiration From Sci-Fi Sources, Looks Incredible

What would a HAL9000 look like if it eye were yellow and sat atop a front panel inspired by an Altair 8800? You’d have today’s feature, [Stephan]’s BerlinUhr, a gorgeous little take on a Berlin Clock.

At Hackaday, we have a soft spot for clock builds. They’ve graced our pages from early times. When we saw this ultra cool Berlin Clock, we couldn’t resist the urge to share it with all of our readers.  For those of you not familiar with a Berlin Clock, it’s a clock that consists of 24 lights, and was the first of its kind back in 1975.

[Stephan]’s build is notable because not only is it a beautiful design, but the work that went into the design and build. At several inches tall, the BerlinUhr is supported solely by a USB-C connection, although it can also be hung on a wall. The RTC is backed up by a CR1216, and an ATtiny167 provides the brains for the operation.

A neat part of the build comes with the KPS-3227 light sensor, used to adjust the LED brightness according to ambient lighting. Rather than being a straightforward part to insert into the PCB, KiCad’s footprint had some pins reversed, causing [Stephan] to learn how to correct it and contribute the fix to KiCad. Well done!

We weren’t kidding about clocks, by the way- check out the link to the Atomic Wrist Watch on this post from 2005, and this Russian VFD based clock from 2006- with video!

Do you have your own favorite clock build you’d love to see grace our pages? Be sure to submit a tip!

Headphones described in article, charging off a powerbank through an orange USB cable

Headphone Cable Trouble Inspires Bluetooth Conversion

[adblu] encountered the ever-present headphone problem with their Sennheiser Urbanite headphones – the cable broke. These headphones are decent, and despite the cable troubles, worth giving a new life to. Cable replacement is always an option, but [adblu] decided to see – what would it take to make these headphones wireless? And while they’re at it, just how much battery life could they get?

Armed with a CSR8635 Bluetooth audio receiver breakout module and a TP4056 charger, [adblu] went on rewiring the headphone internals. The CSR8635 already has a speaker amplifier inside, so connecting the headphones’ speakers didn’t require much effort – apart from general soldering difficulties, as [adblu]’s soldering iron was too large for the small pads on the BT module. They also found a 2400mAh battery, and fit it inside the headphone body after generous amounts of dremel work.

The result didn’t disappoint – not only does everything fit inside the headphone body, the headphones also provided 165 hours of music playback at varying volume. Electronics-wise, it really is that easy to retrofit your headphones with Bluetooth, but you can always go the extra mile and design an intricate set of custom PCBs! If firmware hacks are more to your liking, you can use a CSR8645 module for your build and then mod its firmware.

Photovoltaic Cells In LTSpice

We like to build things using real parts. But we do think the more you can model using tools like LTSpice, the less time you can spend going down dead ends. If you need to model a common component like a resistor or even an active device, most simulators have great models and you can tweak them to have realistic parasitic effects. But what if the component you want isn’t in the library or doesn’t have the fidelity you want? [FesZ] wanted to model photovoltaic cells and had to build his own model. The resulting two videos are well worth watching.

Building your own models in Spice isn’t necessarily very difficult. However, knowing exactly what to add to model different real-world effects can be challenging. The videos do a good job of showing how to mutate a simple diode into one that produces current when exposed to light.

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SpinLaunch And The History Of Hurling Stuff Into Space

It’s fair to say that there’s really no phase of spaceflight that could be considered easy. But the case could be made that the most difficult part of a spacecraft’s journey is right at the very beginning, within the first few minutes of flight. At this point the vehicle’s booster rocket will be fighting with all its might against its own immense propellant-laden mass, a battle that it’s been engineered to win by the smallest of margins. Assuming the balance was struck properly and the vehicle makes its way off of the launch pad, it will still need to contend with the thick sea-level atmosphere as it accelerates, a building dynamic pressure that culminates with a point known as “Max q” — the moment where the air density imposes the maximum structural load on the rocket before quickly dropping off as the vehicle continues to ascend and the atmosphere thins.

Air-launched rockets avoid flying through dense sea level air.

While the vast majority of rocket launches have to contend with the realities of flying through the lower atmosphere, there are some exceptions. By launching a rocket from an aircraft, it can avoid having to power itself up from sea level. This allows the rocket to be smaller and lighter, as it doesn’t require as much propellant nor do its engines need to be as powerful.

The downside of this approach however is that even a relatively small rocket needs a very large aircraft to carry it. For example, Virgin Orbit’s LauncherOne rocket must be carried to launch altitude by a Boeing 747-400 airliner in order to place a 500 kg (1,100 lb) payload into orbit.

But what if there was another way? What if you could get all the benefits of starting your rocket from a higher altitude, without the cost and logistical issues involved in carrying it with a massive airplane? It might sound impossible, but the answer is actually quite simple…all you have to do it throw it hard enough.

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