To Make Reproduction Train Whistles, The Old Ways Are Best

January 21, 2019 by Donald Papp 9 Comments

Late last year, artist [Steve Messam]’s project “Whistle” involved 16 steam engine whistles around Newcastle that would fire at different parts of the day over three months. The goal of the project was bring back the distinctive sound of the train whistles which used to be fixture of daily life, and to do so as authentically as possible. [Steve] has shared details on the construction and testing of the whistles, which as it turns out was a far more complex task than one might expect. The installation made use of modern technology like Raspberry Pi and cellular data networks, but when it came to manufacturing the whistles themselves the tried and true ways were best: casting in brass before machining on a lathe to finish.

The original whistles are a peek into a different era. The bell type whistle has three major components: a large bell at the top, a cup at the base, and a central column through which steam is piped. These whistles were usually made by apprentices, as they required a range of engineering and manufacturing skills to produce correctly, but were not themselves a critical mechanical component.

In the original whistle shown here, pressurized steam comes out from within the bottom cup and exits through the thin gap (barely visible in the image, it’s very narrow) between the cup and the flat shelf-like section of the central column. That ring-shaped column of air is split by the lip of the bell above it, and the sound is created. When it comes to getting the right performance, everything matters. The pressure of the air, the size of the gap, the sharpness of the bell’s lip, the spacing between the bell and the cup, and the shape of the bell itself all play a role. As a result, while the basic design and operation of the whistles were well-understood, there was a lot of work to be done to reproduce whistles that not only operated reliably in all types of weather using compressed air instead of steam, but did so while still producing an authentic re-creation of the original sound. As [Steve] points out, “with any project that’s not been done before, you really can’t do too much testing.”

Embedded below is one such test. It’s slow-motion footage of what happens when the whistle fires after filling with rainwater. You may want to turn your speakers down for this one: locomotive whistles really were not known for their lack of volume.

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Front Door Camera Sends Automatic Alerts By Text

January 21, 2019 by Lewin Day 25 Comments

In these turbulent times, journalists fearmonger and honest citizens fear for the safety of their homes and themselves. Adding some security features can allay these fears, and with the advent of cheap technology, front door cameras have become popular. There’s a wide array of options on the market, but short of watching hours of logged video, they’re not always super useful. Adding some smarts can really help – as [Peter Quinn] has done.

For this project, [Peter] decided on a JeVois smart camera. More than just a USB webcam, it also packs a quad-core processor running machine vision algorithms. This allows object recognition and other tasks to be run on the camera itself. In this setup, [Peter] configured the JeVois camera to detect people. When a human is detected upon the doorstep, the camera sends a message to the connected Raspberry Pi over serial. The Raspberry Pi then captures a JPEG still from the camera over the USB connection, and, using Twilio, sends a notification to [Peter]’s phone.

It’s a well-integrated system that automatically photographs visitors to [Peter]’s home, requiring little to no interaction from the user. We’ve seen other integrated machine vision platforms, too – such as the OpenMV, which got its start as a Hackaday Prize entry, way back in 2017.

This Monowheel Is Bright Orange, And We Want One

January 16, 2019 by Lewin Day 24 Comments

Monowheels are a singular form of transport. Like electric scooters and the Segway, they are remarkably impractical for getting from point A to point B, are expensive to build or buy, and make you look faintly silly as you ride them down the street. However, we’d be hard pressed to find a member of the Hackaday team that wouldn’t at least want a go on one for half an hour. [MakeItExtreme] felt the same way, and built one of their own.

The build starts with a tube bender, used to form 40mm tubing into a continuous circle to form the main wheel. Teflon is then turned to produce several rollers that interface the main wheel to the inner frame. Several small motorbike tyres were cut apart to create the tread to provide some decent grip. Power comes courtesy of a 110cc four stroke engine, allowing this thing to go just fast enough to get the rider seriously injured in the event of an accident. The team reports stability is poor at low speed, but remarkably good once above 30 km/h.

The team did a great job, and we particularly enjoy the bright orange paint scheme and fetching decals that really finish it off well. The monowheel concept is remarkably similar to the diwheel, which we’ve seen applied to old Fords with somewhat terrifying results. Video after the break.

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New Contest: 3D Printed Gears, Pulleys, And Cams

January 16, 2019 by Mike Szczys 40 Comments

One of the killer apps of 3D printers is the ability to make custom gears, transmissions, and mechanisms. But there’s a learning curve. If you haven’t 3D printed your own gearbox or automaton, here’s a great reason to take the plunge. This morning Hackaday launched the 3D Printed Gears, Pulleys, and Cams contest, a challenge to make stuff move using 3D-printed mechanisms.

Adding movement to a project brings it to life. Often times we see projects where moving parts are connected directly to a servo or other motor, but you can do a lot more interesting things by adding some mechanical advantage between the source of the work, and the moving parts. We don’t care if it’s motorized or hand cranked, water powered or driven by the wind, we just want to see what neat things you can accomplish by 3D printing some gears, pulleys, or cams!

No mechanism is too small — if you have never printed gears before and manage to get just two meshing with each other, we want to see it! (And of course no gear is literally too small either — who can print the smallest gearbox as their entry?) Automatons, toys, drive trains, string plotters, useless machines, clockworks, and baubles are all fair game. We want to be inspired by the story of how you design your entry, and what it took to get from filament to functional prototype.

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Arduino Hunts (and Sees) The Wumpus

January 15, 2019 by Tom Nardi 13 Comments

For anyone who’s been fiddling around with computers since the days before VGA, “Hunt the Wumpus” probably brings back fond memories. Developed in 1973, this text game has you move around a system of caves searching for the foul-smelling Wumpus, a vile creature which you must dispatch with your trusty bow and arrow. Some consider it to be one of the very first survival horror games ever developed, a predecessor to the Resident Evil franchise as well as the video game version of Hannah Montana: The Movie.

If the concept of “Hunt the Wumpus” sounds interesting to you, but you just can’t get over the whole text adventure thing, you may be in luck. [Benjamin Faure] has developed a semi-graphical version of the classic horror title which might better appeal to your 21st century tastes. Running on an Arduino Mega 2560 with graphics displayed on a 8 x 8 LED matrix, it’s not exactly DOOM; but at least you won’t have to type everything out.

For his handheld version of “Hunt the Wumpus”, [Benjamin] 3D printed a nice enclosure and adorned it with labels and instructions that look like tiny scrolls, a neat touch for a game that’s so old contemporary players would have called Zork a “next gen” game. While playing you can see where you’ve been and where you are currently thanks to illuminated dots on the MAX7219 display, and there are LEDs to warn you of your proximity to bottomless pits and the Wumpus itself. There’s even a piezo speaker that will chirp when a bat is nearby, which is important as they have a tendency to ruin your day by carrying you away to a random location in the cave.

Most of the game looks like an advanced version of Snake, but [Benjamin] did go through the trouble of adding some rudimentary animations and sound effects that play during specific parts of the game. When you shoot your arrow or get carried away by a bat, you’ll see a “cutscene” of sorts on the LED display. It’s a fairly simple effect, but helps break up the otherwise fairly spartan graphics and might just be enough to keep a youngins’ attention.

If you subtract a dimension, this project is reminiscent of the 1D dungeon crawler we covered last year. But if even one dimension is too many, you could always run the text version of “Hunt the Wumpus“ on your trusty Arduino.

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See The Radioactive World With This Peltier Cloud Chamber

January 13, 2019 by Dan Maloney 17 Comments

Remember when a homemade cloud chamber was a science fair staple? We haven’t participated for decades, but it seemed like every year someone would put a hunk of dry ice in a fish tank, add a little alcohol, and with the lighting just right – which it never was in the gymnasium – you might be lucky enough to see a few contrails in the supersaturated vapor as the occasional stray bit of background radiation whizzed through the apparatus.

Done right, the classic cloud chamber is a great demonstration, but stocking enough dry ice to keep the fun going is a bit of a drag. That’s where this Peltier-cooled cloud chamber comes into its own. [mosivers] spares no expense at making a more permanent, turn-key cloud chamber, which is perched atop a laser-cut acrylic case. Inside that is an ATX power supply which runs a Peltier thermoelectric cooling module. Coupled with a CPU cooler, the TEC is able to drive the chamber temperature down to a chilly -42°C, with a strip of white LEDs providing the required side-lighting. The video below gives a tour of the machine and shows a few traces from a chunk of pitchblende; it’s all pretty tame until [mosivers] turns on his special modification – a high-voltage grid powered by a scrapped electronic fly swatter. That really kicks up the action, and even lets thoriated TIG welding electrodes be used as a decent source of alpha particles.

It’s been a while since we’ve seen a Peltier cloud chamber build around here, which is too bad because they’re great tools for engaging young minds as well as for discovery. And if you use one right, it just might make you as famous as your mother.

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A Turntable For Model Railroads

January 11, 2019 by Lewin Day 17 Comments

Way back when, before diesel-electric locomotives were a thing, trains weren’t really able to go backwards too well. Also it’s sometimes necessary to turn carriages around in a small space. For that, the railway turntable was invented. If you want to implement one on a model layout, this project from DIY & Digital Railworld is for you.

The project is at an early stage – thus far, laying out how to set up an Arduino Uno using a potentiometer to control the speed of a stepper motor, which rotates the turntable. The turntable itself is a 3D printed part sourced from Thingiverse, designed to suit the specific stepper motor used.

This has the easy part sorted – rotating a piece of track through 360 degrees to orient a train properly. However, there’s significant work ahead. Power needs to be hooked up to the rails, and a system for accurately aligning the turntable with outgoing tracks needs to be devised. This is particularly relevant for N-gauge setups, where tolerances are everything.

We’d love to know how you’d tackle the various issues to build a working model turntable in the comments. We’ve seen some serious model railroad builds before around these parts. Video after the break.

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