IC Shortage Keeps Linux Out Of Phone Charger, For Now

September 29, 2021 by 21 Comments

We’ve been eagerly following the development of the WiFiWart for some time now, as a quad-core Cortex-A7 USB phone charger with dual WiFi interfaces that runs OpenWrt sounds exactly like the sort of thing we need in our lives. Unfortunately, we’ve just heard from [Walker] that progress on the project has been slowed down indefinitely by crippling chip shortages.

At this point, we’ve all heard how the chip shortage is impacting the big players out there. It makes sense that automakers are feeling the pressure, since they are buying literally millions of components at a clip. But stories like this are a reminder that even an individual’s hobby project can be sidelined by parts that are suddenly 40 times as expensive as they were when you first put them in your bill of materials.

The new miniature compute board.

In this particular case, [Walker] explains that a power management chip you could get on DigiKey for $1.20 USD a few months ago is now in such short supply that the best offer he’s found so far is $49.70 a pop from an electronics broker in Shenzhen. It sounds like he’s going to bite the bullet and buy the four of them (ouch) that he needs to build a working prototype, but obviously it’s a no go for production.

Luckily, it’s not all bad news. [Walker] has made some good progress on the power supply board, which will eventually join the diminutive computer inside the USB charger enclosure. Part of the trick is that the device is still supposed to be a functional USB charger, so in addition to 5 VDC for the output port, the power supply also needs to produce 1.1 V, 1.35 V, 2.5 V, 3.0 V, and 3.3 V for the computer. We’re glad to see he’s taking the high road with his mains circuitry, making sure to use UL listed components and maintaining proper isolation.

When we last checked in on the WiFiWart back in July, [Walker] had already managed to boot Linux on his over-sized prototype board. Now he’s got PCBs in hand that look far closer to the final size and shape necessary to tuck them into a phone charger. It’s a shame that the parts shortage is slowing down progress, but we’re confident we’ll at least get to see a one-off version of the WiFiWart powered up before the year is out.

101 Uses For An Everready — Flashlight History

September 29, 2021 by 53 Comments

For some reason, I’m always interested in why things are called what they are. For example, I’ve been compelled in the past to research what Absorbine Senior is. Not that it is important, but Absorbine Junior is a smaller size of horse liniment, so you don’t have to buy a drum of ordinary Absorbine just to rub down your sore thumb. So it isn’t a mystery that I would find myself musing over why we call a flashlight a flashlight.

You don’t think of a flashlight as flashing, under normal circumstances, at least. Turns out the answer lies in the history of the device, its poor beginnings, and our willingness to treat imperfect components as though they were much better than they are. That last point, by the way, still has ramifications today, so even if you aren’t a fan of flashlight history, keep reading.

Portable Lighting

Ever since people learned to use fire, there’s been a desire for portable lighting. Torches, candles, and even oil lamps have all had their place. But burning things for light in small cramped spaces leaves a lot to be desired. It isn’t surprising that people quickly turned to electricity when that seemed to be feasible.

Continue reading “101 Uses For An Everready — Flashlight History” →

A r0tring CS-50 scriber. You type, it writes the letters with a pen on your blueprint or technical drawing.

Plotting To Restore A R0tring CS-50

September 29, 2021 by 8 Comments

If you’re of a certain vintage and have ever done any technical drawing, chances are good that you used a r0tring of some kind, be it pencil or pen. Well, r0tring makes more than writing implements.  They also made electronic scribers — a small plotter that pens ISO lettering on technical drawings based on typed input. This was a huge time saver over doing it freehand or stenciling each letter. The CS-50 is designed to hold the top-of-the-line r0tring drawing pen, which turned out to be the most expensive part of this restoration aside from the time spent sniffing out issues.

[Atkelar] likes to open things up and give them a visual inspection before powering them on. We think this is good practice, even if the suspense kills you. But really, [Atkelar] did so much more than that. He started by replacing the likely late-80s-era coin cell even though it registered north of 3 V. Then he swapped out all the electrolytic caps and one tantalum, cleaned the rubber dome keyboard parts with a cheap electric toothbrush, (another great idea), and completely disassembled the x-y mechanism to clean and re-oil it.

Continue reading “Plotting To Restore A R0tring CS-50” →

Teardown: Sling Adapter

September 29, 2021 by 27 Comments

The consumer electronics space is always in a state of flux, but perhaps nowhere is this more evident than with entertainment equipment. In the span of just a few decades we went from grainy VHS tapes on 24″ CRTs to 4K Blu-rays on 70″ LED panels, only to end up spending most of our viewing time watching streaming content on our smartphones. There’s no sign of things slowing down, either. In fact they’re arguably speeding up. Sure that 4K TV you bought a couple years back might have HDR, but does it have HDMI 2.1 and Dolby Vision?

So it’s little surprise that eBay is littered with outdated A/V gadgets that can be had for a pennies on the dollar. Take for example the SB700-100 Sling Adapter we’re looking at today. This device retailed for $99 when it was released in 2010, and enabled Dish Network users to stream content saved on their DVR to a smartphone or tablet. Being able to watch full TV shows and movies on a mobile device over the Internet was a neat trick back then, before Netflix had even started rolling out their Android application. But today it’s about as useful as an HD-DVD drive, which is why you can pick one up for as little as $5.

Of course, that’s only a deal if you can actually do something with the device. Contemporary reviews seemed pretty cagey about how the thing actually worked, explaining simply that plugging it into your Dish DVR imbued the set-top box with hitherto unheard of capabilities. They assured the reader that the performance was excellent, and that it would be $99 well spent should they decide to dive headfirst into this brave new world where your favorite TV shows and movies could finally be enjoyed in the bathroom.

Now, more than a decade after its release, we’ll crack open the SB700-100 Sling Adapter and see if we can’t figure out how this unusual piece of tech actually worked. Its days of slinging the latest episode of The Office may be over, but maybe this old dog can still learn a few new tricks.

Continue reading “Teardown: Sling Adapter” →

BFree Brings Intermittent Computing To Python

September 29, 2021 by 16 Comments

Generally speaking, we like our computing devices to remain on and active the whole time we’re using them. But there are situations, such as off-grid devices that run on small solar cells, where constant power is by no means a guarantee. That’s where the concept of intermittent computing comes into play, and now thanks to the BFree project, you can develop Python software that persists even when the hardware goes black.

Implemented as a shield that attaches to a Adafruit Metro M0 Express running a modified CircuitPython interpreter, BFree automatically makes “checkpoints” as the user’s code is running so that if the power is unexpectedly cut, it can return the environment to a known-good state instantaneously. The snapshot of the system, including everything from the variables stored in memory to the state of each individual peripheral, is stored on the non-volatile FRAM of the MSP430 microcontroller on the BFree board; meaning even if the power doesn’t come back on for weeks or months, the software will be ready to leap back into action.

In addition to the storage for system checkpoints, the BFree board also includes energy harvesting circuity and connections for a solar panel and large capacitor. Notably, the system has no provision for a traditional battery. You can keep the Metro M0 Express plugged in while developing your code, but once you’re ready to test in the field, the shield is in charge of powering up the system whenever it’s built up enough of a charge.

The product of a collaboration between teams at Northwestern University and Delft University of Technology, BFree is actually an evolution of the battery-free handheld game they developed around this time last year. While that project was used to raise awareness of how intermittent computing works, BFree is clearly a more flexible platform, and is better suited for wider experimentation.

We’ve seen a fair number of devices that store up small amounts of energy over the long term for quick bouts of activity, so we’re very interested to see what the community can come up with when that sort of hardware is combined with software that can be paused until its needed.

an image of the volume adjustment board

Is Your Movie Too Loud? Can’t Hear The Dialogue? This Circuit Can Help.

September 29, 2021 by 67 Comments

Everyone loves watching movies, that is, so long as you can hear what the characters on screen are saying. [GreatScott] found this second part difficult while watching through BladeRunner 2049, so he designed an automatic volume adjuster to assist.

At a high level, the solution is fairly straightforward; when there is loud music playing in a movie, turn the volume down. The challenge is how to actually achieve that. The first step was controlling the volume. To avoid having to modify or damage his sound system, [GreatScott] opted instead to mimic the volume up and down signals of his remote over IR. Using the very handy IRremote library for Arduino and its built-in decoding functionality, he was able to identify and replicate the signals with his own IR LED.

The second step in this process was measuring the volume of the movie. [GreatScott] achieved this with a microphone and amplifier circuit, that was then piped into one of the analog pins of the Arduino Pro Micro at the heart of the build. Since the audio being sampled could have a frequency as high as 20 kHz, the ADC Prescaler had to be adjusted from its standard value, which would have only permitted measurements at less than 5 kHz.

The third step was writing the algorithm to detect loud music and adjust the volume accordingly. The Arduino will measure the audio until a sound greater than the dead band value, set with one of the two onboard potentiometers, is detected. This then triggers the Arduino to start a timer, to see how frequently the upper limit is being surpassed. If it is just one or two occasionally loud noises (like a scream, a clap, whistling, etc.) the Arduino will not take any action, but multiple loud noises in rapid succession will then trigger the volume down command over the IR LED. A second potentiometer allows for adjustment of this timer’s critical value, so that you can make the system respond faster or slower depending on the movie.

Once the sound has been detected to have dropped down below a critical vaue, the Arduino assumes that the movie is back to dialog and will increase the volume by the number of times it decreased it before, leaving you back at the perfect volume.

Maybe you’re the type that cares more for the visuals of a movie, rather than the audio. In that case, this e-paper movie display will be perfect for giving you time to appreciate every frame!

Continue reading “Is Your Movie Too Loud? Can’t Hear The Dialogue? This Circuit Can Help.” →

A shirt with carbon nanotube threads stitched into a shirt monitor the wearer's heart rate.

Sew-able Carbon Nanotube Thread Could Spin A Lot Of Awesome

September 28, 2021 by 18 Comments

Plenty of people just plain dislike wearing jewelry, even (or especially) smart watches. Nevertheless, they’d like to have biofeedback like everybody else. Well, we watch-less ones have something to look forward to, because a group of graduate students at Rice University have created extremely strong conductive thread woven from carbon nanotubes, which can be sewn into standard athletic clothing and used as electrodes, antennas, or simply as ballistic protection.

At 22 microns wide, the original carbon nanotubes were too skinny to use as thread. Instead, the team braided together three bundles of seven ‘tubes each using the type of machine that model boat builders use to make tiny rigging. Then they zig-zag stitched the threads into a shirt, which gives the stitches added flexibility. This thread maybe as strong and conductive as metal, but the fibers are soft and flexible, and most importantly, machine-washable. Between its strength and conductivity, this thread could have a long list of applications from military down to civilian. Check out the introduction in the video after the break.

For now, the shirt has to be pretty snug, but future garments could easily have higher concentrations of nano-threads in order to get a better signal. Good thing, because we’re still carrying around our COVID nineteen — aka the weight we’ve gained since the longest March of anyone’s life, and never liked tight shirts anyway.

What else can carbon nanotubes do? Plenty, like keep 3D prints from delaminating.

Continue reading “Sew-able Carbon Nanotube Thread Could Spin A Lot Of Awesome” →