An Arduino-Based Flute Playing Machine

January 11, 2020 by 9 Comments

It’s one thing to be able to transcribe music from a flute, and it’s another to be able to make a flute play pre-written music. The latter is what [Abhilash Patel] decided to pursue in the flute player machine, an Arduino-based project that uses an air flow mechanism and PVC pipes to control the notes produced by a makeshift flute. It’s currently able to play 17 notes, just over two octaves starting from the lowest frequency of E.

In order to play songs, the tones have to either be directly coded and uploaded to the Arduino, composed with a random note generator, or detected from a microphone. While a real flute can be used for the machine, [Patel] uses a PVC flute, constructed with some knowledge of flute playing.

The resonant frequency is based on the effective length, hole sizes, and pipe diameter, so it is fairly difficult to correctly tune a homemade flute. Nevertheless, calculating the length as c/2f where c is the speed of sound (~345 m/s) and f is the frequency of the note can help with identifying the location of the holes. [Patel] cut the PVC pipe and sealed off one end, drilling a blowing hole at 1.5 x the pipe diameter. After playing the flute, the end of the pipe was filled until the frequency exactly matched the desired note.

The hole covering uses cuttings of pipe attached to a cable connecting to a servo. The motors are isolated inside a box to keep the wires clear and area all able to be powered with 5 V. As for the software, the code is primarily used to control when the fan is blowing and which holes are covered to produce a note.

Listen to the flute play “My Heart Will Go On” from Titanic in the video below. Now the next step might just be making the flute playing machine automatically play sheet music – imagine the possibilities!

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Stacks Of Spring Washers Power The Drawbar On This CNC Mill Conversion

January 11, 2020 by 25 Comments

With Tormach and Haas capturing a lot of the entry-level professional market for CNC machines, we don’t see too many CNC conversions of manual mills anymore. And so this power drawbar conversion for a Precision Matthews mill really caught our eye.

What’s that, you say? Didn’t [Physics Anonymous] already build a power drawbar for a mill? They did, and it was quite successful. But that was based on a pneumatic impact wrench, and while it worked fine on a manual mill, the same approach would be a bit slow and cumbersome on a CNC mill. For this build, they chose a completely different approach to providing the necessary upward force to draw the collet into the collet holder and clamp down on the tool: springs. Specifically, Belleville spring washers, which are shaped like shallow cups and can exert tremendous axial force over a very short distance.

[PA] calculated that they’d need to exert 2,700 pounds (12,000 Newtons) of force over a length of a couple of inches, which seems outside the Belleville washer’s specs. Luckily, the springs can be stacked, either nested together in “series” to increase the load force, or alternating in “parallel” to apply the rated force over a greater distance. To compress their stack, they used a nifty multi-stage pneumatic cylinder to squash down the springs and release the collet. They also had to come up with a mechanism to engage to machine’s spindle only when a tool change is called for. The video below details the design and shows the build; skip to 11:32 to see the drawbar in action.

We’re looking forward to the rest of [Physics Anonymous]’ conversion. They’re no strangers to modifying off-the-shelf machines to do their bidding, after all – witness their improvements to an SLA printer.

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Building A Real Wooden Table Saw

January 11, 2020 by 43 Comments

A table saw is one of those tools that aren’t strictly necessary to have, but immensely helpful if you do happen to have one around. The folks at [I Build It] have made a three part series that features a homemade table saw build, so you can finally get around to adding one to your makerspace.

The build uses a real table saw arbor and is made from Baltic birch plywood and solid wood, with some plastic sheets for the trunnions and top. The blade is housed in a blade lift made out wooden panels with a pivot point and slot for the lift mechanism. Bearings allow the blade the freedom of movement, while a curved cutout allows it to stay flat against the wall of the slot while the blade lift mechanism moves.

Meanwhile a reused motor from a previous table saw is dusted, cleaned, and rewired to run in reverse. While most table saws only need two trunnions, a third is used for supporting the motor, since it has to move with the lift and tilt. Once the lift/tilt mechanism is complete, the frame for the table saw is more straightforward, with many steps involving clamping, measuring, cutting, fitting, and painting the assembly. For the final few steps, a switched is mounted outside the table saw in a small box that connected to the power supply and motor, as well as a shop vac for handling dust collection from the saw. While the enclosure isn’t a metal box, as long as the connections are secured properly the wires shouldn’t come loose.

If you want to see other examples of homemade table saws, check out this teeny tiny saw and this kid-friendly table saw build.

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This Ugly Christmas Sweater Can Set You On Fire

January 11, 2020 by 9 Comments

While Christmas may have just passed, there’s just enough time left in winter to justify wearing your ugly Christmas sweaters for a few more days. If you’re not one of the lucky ones with an old sweater from Grandma, you can still turn your least favorite sweater into the most epic flame-throwing Christmas sweater there ever was.

[JAIRUS OF ALL], maker of explosive and other dangerous ideas, came up with a DIY ugly Christmas sweater that shoots flames on command. In order to produce the flame-throwing effect, he uses piping from a fish tank airline hose with a T connector attached to one end and epoxied to the middle of the sweater. The piping runs down the sweater to a can of butane fuel that he can control from the nozzle. Once the fuel is being released, he uses a lighter to initiate the flames from the sweater.

The flames are quite impressive, so definitely use caution if you intend to replicate this build in any way. It would be helpful to have a friend with a CO2 fire extinguisher nearby as well.

For a less life-threatening build, fellow builder [Price] created a Christmas tree-themed sweater lined with LEDs and USB-powered figurines, connected to a power supply in his pocket.

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A Simple POV Globe Via APA102

January 10, 2020 by 30 Comments

POV builds come in all shapes and sizes, and typically rely on LEDs for their high light output and fast response time. With this in mind, [Great Scott] grabbed some LED strip off the shelf and set about whipping up a POV LED globe.

Being a spinning POV build, it’s necessary to consider how to get power to the rotating elements. [Great Scott] decided to go with a simple solution of putting a LiPo battery on the rotating assembly, which runs the LEDs and Arduino Nano at the heart of the operation. The LEDs in question are of the APA102 type, making them readily addressable and capable of a wide color gamut. It’s all spun by a simple brushed DC motor, running from a separate supply at the base of the platform.

It’s very much a hacker build, held together with duct tape and zipties. Despite this, it looks tidy when in operation, as all of the important hardware is hidden at the centre of the globe. There’s a bit of a vibration problem, but [Great Scott] reckons this can be fixed with some frame modifications.

We’d love to see the build run some more advanced operations, like a representation of the Earth, or some kind of sun clock. If you’re interested in learning more about POV displays, we’ve got the primer you need. Video after the break.

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Building A Low-Tech Website For Energy Efficiency

January 10, 2020 by 38 Comments

In an age of flashy jQuery scripts and bulky JavaScript front-end frameworks, loading a “lite” website is like a breath of fresh air. When most of us think of lightweight sites, though, our mind goes to old-style pure HTML and CSS sites or the intentionally barebones websites of developers and academics. Low-tech Magazine, an intentionally low-tech and solar-powered website, manages to incorporate both modern web aesthetics and low-tech efficiency in one go.

Rather than hosting the site on data centers – even those running on renewable power sources – they have a self-hosted site that is run on solar power, causing the site to occasionally go off-line. Their model contrasts with the cloud computing model, which allows more energy efficiency at the user-side while increasing energy expense at data centers. Each page on the blog declares the page size, with an average page weight of 0.77 MB, less than half of the average page size of the top 500,000 most popular blogs in June 2018.

Some of the major choices that have limited the size of the website include building a static site as opposed to a dynamic site, “dithering” images, sparing a logo, staying with default typefaces, and eliminating all third-party tracking, advertising services, and cookies. Their GitHub repository details the front-end decisions  including using unicode characters for the site’s logo rather than embedding an SVG. While the latter may be scalable and lightweight in format it requires distribution to the end-user, which can involve a zipped package with eps, ai, png, and jpeg files in order to ensure the user is able to load the image.

As for the image dithering, the technique allows the website to maintain its characteristic appearance while still minimizing image quality and size. Luckily for Low-tech Magazine, the theme of the magazine allows for black and white images, suitable for dithering. Image sprites are also helpful for minimizing server requests by combining multiple small images into one. Storage-wise, the combined image will take up less memory and only load once.

There are also a few extraneous features that emphasize the website’s infrastructure. The background color indicates the capacity of the solar-charged battery for the website’s server, while other stats about the server’s location (time, sky conditions, forecast) also help with making the website availability in the near future more visible. Who knows, with the greater conscience on environmental impact, this may be a new trend in web design.

Arduino Pedometer Counts Your Steps

January 10, 2020 by 10 Comments

There’s a trend in corporate America that has employees wear a step counter — technically a pedometer — and compete in teams to see who can get the most number of steps. We wonder how many people attach the device to an electric drill and win the competition easily. However if you want to do your own measurements, [Ashish Choudhary] has plans for making a pedometer with an Arduino. The device isn’t tiny, but as you can see in the video below it seems to work.

For the extra size, you do get some features. For one, there is a 16×2 LCD display and an ADXL335 accelerometer, and you can probably imagine some other cool features for such a device.

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