A Python Serial Terminal To Get You Out Of A Jam

November 28, 2019 by 21 Comments

When fiddling around with old computers, you can occasionally find yourself in a sticky situation. What may be a simple task with today’s hardware and software can be nearly impossible given the limited resources available to machines with 20 or 30 years on the clock. That’s where [bison] recently found himself when he needed to configure a device over serial, but didn’t have any way of installing the appropriate terminal emulator on his Fujitsu Lifebook C34S.

His solution, since he had Python 2.6 installed on the Debian 6 machine, was to write his own minimal serial terminal emulator. He intended for the code to be as terse as possible so it could be quickly typed in, should anyone else ever find themselves in need of talking to a serial device on Linux but can’t get screen or minicom installed.

The code is very simple, and even if you never find yourself needing to fire up an impromptu terminal, it offers an interesting example of how straightforward serial communications really are. The code opens up the /dev/ttyS0 device for reading, and after appending the appropriate return character, pushes the user’s keyboard input into it. Keep looping around, and you’ve got yourself an interactive terminal.

With this program written, [bison] was able to connect the 266 MHz C34S to his Retro WiFi SI, a modem adapter that bridges the gap between a vintage computer and modern wireless network. Gadgets like these allow you to browse BBSes as the creator intended, and can be fashioned with nothing more exotic than an ESP8266 running some open source code.

Add LEDs To Your Stained Glass

November 28, 2019 by 20 Comments

Stained glass is an art form that goes back many centuries, with the churches and cathedrals of Europe boasting many stunning examples from the mediaeval masters of the craft. You do not however have to go to York or Chartres cathedrals to experience stained glass, for it remains a vibrant and creative discipline with many contemporary practitioners. One thing the stained glass of today has in common with that of yesteryear though is that it remains static, being composed of pieces of glass held together by metal strips. This is something that [Frank Zhao] has addressed as he has evolved a technique that allows him to incorporate LEDs into static stained glass, making for a particularly eye-catching effect.

It’s likely that we join many readers in not knowing the intricacies of making a piece of stained glass, so his is a fascinating write-up for its step-by-step run-through. His stained glass cat has pieces of glass edged with copper tape, which he then solders together. Driving the LEDs is not something that should be alien to us, but his method of using the copper-and-solder stained glass joints as conductors for them by creating strategically placed cuts is very effective. The final effect is of a homogeneous piece without the cuts being particularly visible , but with a pleasing array of lights on the cat’s tail. Those of us for whom stained glass production is new have learned something of the technique, and stained glass artists have seen their craft do something completely new.

Stained glass hasn’t featured here too often, the closest we’ve come is this striking fake stained glass Iron-Man themed panel a few years ago.

A Printed Case For Your ESP Environmental Sensors

November 28, 2019 by 16 Comments

We’ve said it before but it’s worth repeating: rolling your own hardware solution is ridiculously easy these days. If you want to make a network attached environmental sensor, you wire a DHT11 up to an ESP8266 and you’re done. Time to move onto the software. In fact, it can take longer to come up with some kind of suitable enclosure for your hardware project than it does to assemble the thing.

Which is why [Pixel Hawk] has come up with this elegant 3D printed enclosure for the ESP8266 and ESP32. It’s designed to hold the microcontroller in the bottom compartment, while the environmental sensor (either the DHT11 or DHT22) is mounted to the top so it’s exposed to the outside. The case snap fits together so you don’t have to worry about gluing it, and there’s even an opening so you can keep the USB cable plugged in.

In the notes for the design, he mentions that in testing it was determined that the heat of the ESP itself can skew the temperature readings. So he recommends putting the microcontroller to sleep whenever possible, and keeping reads short so the enclosure doesn’t have time to heat up. He’s also created an alternate version of the case with more openings which should help combat this issue if you need to keep the chip awake.

If you’re looking for a complete solution, [Pixel Hawk] has included the source code he personally used to get his ESP32 sensor talking to Blynk, but you certainly don’t have to go that route if you don’t want to. There’s no shortage of existing projects out there that will help you get started with whole-house environmental monitoring. Our very own [Elliot Williams] happens to be partial to MQTT when he wants to get all his gadgets to play nice.

In Case You Cannot Make It To An Escape Room

November 27, 2019 by 17 Comments

Escape rooms are awesome for people who like to solve puzzles, see how things work, or enjoy a mystery. Everyone reading this falls into at least one of those categories. We enjoy puzzles and mysteries, but we have a fondness for seeing how things work. To this end, we direct your attention to [doktorinjh]’s “Bomb Disarming Puzzle in a Suitcase” Game, which is a mysterious puzzle box he built himself. I guess the mystery is mostly in the gameplay, which you can watch below because he shows us his build photos and describes the hardware inside.

At its heart is an Arduino Mega, a wise choice since our back-of-the-napkin estimation puts his I/O count over forty-five and the Mega can handle them all with a few pins to spare. Working inside the confines of a briefcase came with its own challenges, but we adore the way he used the hexagon theme in the top panel to allow for knob clearance. It was so subtle that we almost missed it.

The escape room theme is delightful, and we appreciate the mix of games, aesthetics, and techno-trickery in many forms.

Continue reading “In Case You Cannot Make It To An Escape Room” →

A Single-Digit-Micrometer Thickness Wood Speaker

November 27, 2019 by 22 Comments

Researchers have created an audio speaker using ultra-thin wood film. The new material demonstrates high tensile strength and increased Young’s modulus, as well as acoustic properties contributing to higher resonance frequency and greater displacement amplitude compared to a commercial polypropylene diaphragm in an audio speaker.

Typically, acoustic membranes have to remain very thin (on the micron scale) and robust in order to allow for a highly sensitive frequency response and vibrational amplitude. Materials made from plastic, metal, ceramic, and carbon have been used by engineers and physicists in an attempt to enhance the quality of sound. While plastic thin films are most commonly manufactured, they have a pretty bad impact on the environment. Meanwhile, metal, ceramic, and carbon-based materials are more expensive and less attractive to manufacturers as a result.

Cellulose-based materials have been making an entrance in acoustics research with their environmentally friendly nature and natural wooden structure. Materials like bagasse, wood fibers, chitin, cotton, bacterial cellulose, and lignocellulose are all contenders for effective alternatives to parts currently produced from plastics.

The process for building the ultra-thin film involved removing lignin and hemicellulose from balsa wood, resulting in a highly porous material. The result is hot pressed for a thickness reduction of 97%. The cellulose nano-fibers remain oriented but more densely packed compared to natural wood. In addition, the fibers required higher energy to be pulled apart while remaining flexible and foldable.

At one point in time, plastics seemed to be the hottest new material, but perhaps wood is making a comeback?

[Thanks Qes for the tip!]

Bringing The NES Cartridge Into The USB Age

November 27, 2019 by 7 Comments

An NES cartridge in its most basic form is a surprisingly simple device, it contains two ROMs hosting all the code and assets of its game, and a Nintendo code chip that provided what was a state-of-the-art consumer DRM system for the 1980s. Decades later its inner workings have been extensively reverse-engineered, and there have been quite a few custom and reprogrammable cartridge designs produced.

This hasn’t stopped [Troy Denton] and [Brad Taylor] making a cartridge of their own though, and the result of their labours is a fully USB reprogrammable cartridge for the Nintendo Entertainment System. It provides nonvolatile storage and is a simpler design than you might expect, using a pair of 1 megabit Flash chips and emulating Nintendo’s DRM with an ATtiny microcontroller.

In itself it’s an interesting enough design, but what makes the write-up stand out is the description of having the boards manufactured by a PCBA service, and their subsequent debugging. A surface-mount micro USB socket that shorted out the USB power required a bit of rework to place Kapton tape beneath it, while another clever patch uses the NES clock signal to provide a read-only line for the memory. It’s also interesting to hear about their manual “crowdfunding” approach which was to ask around if anyone else wanted one so they could bring unit cost down by producing more cartridges.

If you’re interested in the NES DRM system, it’s a subject we’ve touched on in the past.

US Air Force Says They’re Developing An Open Source Jet Engine; We Say Show Us The Design

November 27, 2019 by 46 Comments

The economies of scale generally dictate that anything produced in large enough numbers will eventually become cheap. But despite the fact that a few thousand of them are tearing across the sky above our heads at any given moment, turbine jet engines are still expensive to produce compared to other forms of propulsion. The United States Air Force Research Laboratory is hoping to change that by developing their own in-house, open source turbine engine that they believe could reduce costs by as much as 75%.

The Responsive Open Source Engine (ROSE) is designed to be cheap enough that it can be disposable, which has obvious military applications for the Air Force such as small jet-powered drones or even missiles. But even for the pacifists in the audience, it’s hard not to get excited about the idea of a low-cost open source turbine. Obviously an engine this small would have limited use to commercial aviation, but hackers and makers have always been obsessed with small jet engines, and getting one fired up and self-sustaining has traditionally been something of a badge of honor.

Since ROSE has been developed in-house by the Air Force, they have complete ownership of the engine’s intellectual property. This allows them to license the design to manufacturers for actual production rather than buying an existing engine from a single manufacturer and paying whatever their asking price is. The Air Force will be able to shop ROSE around to potential venders and get the best price for fabrication. Depending on how complex the engine is to manufacture, even smaller firms could get in on the action. The hope is that this competition will serve to not only improve the design, but also to keep costs down.

We know what you’re thinking. Where is the design, and what license is it released under? Unfortunately, that aspect of ROSE seems unclear. The engine is still in development so the Air Force isn’t ready to show off the design. But even when it’s complete, we’re fairly skeptical about who will actually have access to it. Open Source is in the name of the project and to live up to that the design needs to be available to the general public. From a purely tactical standpoint keeping the design of a cheap and reliable jet engine away from potential enemy states would seem to be a logical precaution, but is at cross purposes to what Open Source means. Don’t expect to be seeing it on GitHub anytime soon. Nuclear reactors are still fair game, though.

[Thanks to Polymath99 for the tip.]