Month: April 2021

Compute Like It Is 1975: 6th Edition Unix Reborn

April 21, 2021 by 13 Comments

If you crave experiencing or reliving what computing was like “back then” you have a lot of options. One option, of course, is to load an emulator and pretend like you have the hardware and software you are interested in. Another often expensive option is to actually buy the hardware on the used market. However, [mit-pdos] has a different approach: port the 6th edition of Unix to RISC-V and use a modern CPU to run an old favorite operating system.

It isn’t an exact copy, of course, but Xv6 was developed back in 2006 as a teaching operating system at MIT. You can find resources including links to the original Unix source code, commentary on the source code, and information about the original PDP 11/40 host computer on the project’s main page.

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Build Your Own Bluetooth Notification Ticker

April 21, 2021 by 17 Comments

Stock tickers were telegraph-based machines from the 19th century, and quickly fell by the wayside with the advent of computer replacements from the 1960s onwards. However, there’s something charming about small machines that deliver us paper strips of information – as demonstrated by this notification ticker from [DIYprojects] (Russian language, Google Translate link).

The heart of the build is an Arduino Mini, which receives the text content of smartphone notifications via a Bluetooth module hooked up to its serial port. The machine mounts a small roll of paper strip, which is pulled along by a stepper motor fitted with a rubber earbud for added grip. The pen is moved along the paper by a servo using a Lambda mechanism to allow it to move nicely perpendicular to the paper’s direction of travel. Instead of moving the pen up and down, the paper is pushed into the pen by a solenoid mounted underneath.

It’s a fun little project, and one we can imagine being great for educational purposes. It teaches skills required to work with steppers, servos, solenoids and Bluetooth, all at once. It’s a little different from some other pen plotter designs, but the ticker format has a certain charm that’s hard to replicate any other way. Video after the break.

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A Hot-Swappable Battery Grip Keeps The Camera Rolling

April 21, 2021 by 14 Comments

There’s nothing worse than being in the middle of an important shot, only to have the camera’s batteries die on you. The losses can be very real, so it’s best to avoid them entirely. In an effort to do so, [funkster] built himself a battery grip for his Canon EOS M.

The hack is based around the venerable 18650 battery, packing 3.6V of lithium-ion goodness into a compact metal can. [funkster]’s build has slots for two of these cells, powering the camera off of one and keeping the other in reserve. The cells are monitored by a STM32 microcontroller, which switches from one battery to another as they run out or are removed. This allows batteries to be swapped while the camera is on – a highly useful feature. There’s even an OLED display to keep an eye on the state of charge of each cell.

The manner in which power is connected to the camera is rather amusing. An original Canon battery that slides inside the camera was gutted and turned into a simple adapter for the battery port. The battery grip, which wraps around the camera body, connects to this via pin headers that pass through a hole drilled in the camera’s case. It’s a permanent mod, but one [funkster] is happy with for the added usability – especially as doing it this way still provides easy access to the SD card slot.

Keeping a camera juiced on the go can be a headache without the right gear. [funkster] demonstrates that if you can’t buy it, you can always build it yourself. If your problem isn’t battery power, but your camera is overheating, you can of course fix that too. Video after the break.

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Ferrofluid Dances In Custom Bluetooth Speaker

April 21, 2021 by 12 Comments

Ferrofluids, as the name implies, are liquids that respond to magnetic fields. They were originally developed for use by NASA as rocket fuel but are available to the general public now for anyone who wants to enjoy their unique properties. For [Dakd Jung], that meant building a special chamber into a Bluetooth speaker that causes the ferrofluid inside to dance along with the rhythm of the music.

This project isn’t quite as simple as pushing the ferrofluid container against a speaker, though. A special electromagnetic device similar to a speaker was used specifically to manipulate the fluid, using a MSGEQ7 equalizer to provide the device with only a specific range of frequencies best tailored for the fluid’s movement. The project includes two speakers for playing the actual music that point upward, and everything is housed inside of a 3D-printed case. There were some additional hurdles to overcome as well, like learning that the glass needed a special treatment to keep the ferrofluid from sticking to it.

All in all it’s a unique project that not only brings sound to a room but a pleasing physical visualization as well. Being able to listen to music or podcasts on a portable speaker, rather than the tinny internal speakers of a phone or laptop, is the sort of thing you think you can live without until you get used to having higher quality sound easily and in every place you go. And, if there’s a way to improve on that small but crucial foundation with something like a dancing ferrofluid that moves with the music the speaker is playing, then we’re going to embrace that as well.

Hacking An Air Assist For The Ortur Laser

April 21, 2021 by 13 Comments

Getting great results from a laser cutter takes a bit of effort to make sure all of the settings are just right. But even then, if the air between the material and the laser source is full of smoke and debris it will interfere with the laser beam and throw off the results. The solution is to add air assist which continuously clears that area.

Earlier this year I bought an Ortur laser engraver/cutter and have been hacking on it to improve the stock capabilities. last month I talked about putting a board under the machine and making the laser move up and down easily. But I still didn’t have an air assist. Since then I found a great way to add it that will work for many laser cutter setups.

I didn’t design any of these modifications, but I did alter them to fit my particular circumstances. You can find my very simple modifications to other designs on Thingiverse. You’ll also find links to the original designs and you’ll need them for extra parts and instructions, too. It is great to be able to start with work from talented people and build on each other’s ideas.

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BMW Pushing Hard For Solid-State Battery Tech; Plans Demo By 2025

April 21, 2021 by 26 Comments

Plenty of development is ongoing in the world of lithium batteries for use in electric vehicles. Automakers are scrapping for every little percentage gain to add a few miles of range over their competitors, with efforts to reduce charging times just as frantic as well.

Of course, the real win would be to succeed in bringing a bigger, game-changing battery to market. Solid state batteries fit the bill, potentially offering far greater performance than their traditional lithium counterparts. BMW think there’s merit in the technology, and have announced they intend to show off a solid-state battery vehicle by 2025.

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Auto Ball Launcher Will Be Your Dog’s New Best Friend

April 21, 2021 by 22 Comments

If there’s one bright spot on the blight that is this pandemic, it’s got to be all the extra time we’re spending with our pets. Dogs especially love that we’re home all the time and want to spend it playing, but sometimes you need to get stuff done. Why not head outside with your laptop and keep the dog happy with an automatic ball launcher?

This is a work in progress, and [Connor] plans to publish a BOM and the STL files once it’s all finished. For now, it’s a working prototype that shoots a ball into the air and about 25 feet away, from the looks of it. Far enough to be fun, but not so far that it goes over the fence.

All [Connor] has to do is drop the ball in the top, which you know is going to lead to training the dog to do it himself. A proximity sensor detects the ball and starts up a pair of 540 R/C motors, then a servo drops the ball down the internal chute. The motors spit the ball out with great force with a pair of profiled, 3D-printed wheels that are controlled by a Turnigy ESC and an Arduino Nano.

In the future, [Connor] plans to print a cover for the electronics and enlarge the funnel so it’s easier for the dog to drop in the ball. Check out the brief demo and build video after the break.

All dogs should be able to get in a good game of fetch as often as they want, even if they happen to be blind.

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