Dog Bowls Show The Versatility Of Ceramic Slip Casting

January 3, 2021 by 18 Comments

Here at Hackaday, we feature projects that are built of just about every material imaginable. Silicon-spangled fiber-reinforced epoxy resin is our primary medium, but we see plastic, wood, steel, aluminum, and even textiles from time to time. It’s not often we see slip-cast ceramic molding, though, and when it pops up, it’s always good to take a look at this versatile manufacturing method.

The back-story on this one is that [thoughtfulocean], a mechanical engineer idled by COVID lockdowns, wanted custom water bowls for his dogs, one of whom is clearly a grumpy Ewok. The design started with a 3D-print of the final vessel, printed in sections and glued together. These were used to create a two-piece plaster mold into which a watery slurry of clay, or slip, was poured. The plaster mold dehydrates the slip, leaving behind a semi-solid layer of clay of the desired thickness once the excess slip is poured off. The resulting casting is then fired in a kiln and glazed.

Of course, [thoughtfulocean] ran into a few problems along the way. The first mold was warped thanks to the mold box bowing under pressure from the plaster, so the whole molding process had to be revamped. The finished bowl also shrunk less than expected after firing, which led to some more revisions. But the finished bowl look really nice, and the included pump and filter keeps the Ewok’s water free from the yuck a dog’s face can introduce. As a bonus, it sounds like [thoughtfulocean] might have created a marketable product from all this. Take that, COVID!

Slip-casting ceramic may not be all that common around here, but ceramic as a material isn’t exactly a stranger. And who says slip casting is limited to ceramic? After all, we’ve seen a similar method used with plastic resin.

[via r/engineering]

An Arduino And A CD-ROM Drive Makes A CD Player

January 3, 2021 by 49 Comments

In an age of streaming media it’s easy to forget the audio CD, but they still remain as a physical format from the days when the “Play” button was not yet the “Pay” button. A CD player may no longer be the prized possession it once was, but it’s still possible to dabble in the world of 120 mm polycarbonate discs if you have a fancy for it. It’s something [Daniel1111] has done with his Arduino CD player, which uses the little microcontroller board to control a CD-ROM drive via its IDE bus.

The project draws heavily from the work of previous experimenters, notably ATAPIDUINO, but it extends them by taking its audio from the drive’s S/PDIF output. A port expander drives the IDE interface, while a Cirrus Logic WM8805 S/PDIF transceiver handles the digital audio and converts it to an I2S stream. That in turn is fed to a Texas Instruments PCM5102 DAC, which provides a line-level audio output. All the code and schematic can be found in a GitHub repository.

To anyone who worked in the CD-ROM business back in the 1990s this project presses quite a few buttons, though perhaps not enough to dig out all those CDs again. It would be interesting to see whether the I2S stream could be lifted from inside the drive directly, or even if the audio data could be received via the IDE bus. If you’d like to know a bit more about I2S , we have an article for you.

Blackboard Becomes Tidy Pen Plotter

January 3, 2021 by 7 Comments

Printers are all well and good, but they’re generally limited to smaller paper sizes and use expensive ink. If you instead want to produce art on a larger scale, a plotter can be a great way to go. [tuenhidiy] built a tidy example using an old blackboard as a base.

These days, such a build is quite easily approachable, thanks to the broad DIY CNC and 3D printing communities. The plotter consists of a pair of stepper motors, driven by an off-the-shelf RAMPS 1.4 controller and an Arduino Mega 2560. The motors are mounted at the top corners of the blackboard, and move the pen holder via a pair of toothed belts, counter-weighted for stability. The pen holder itself mounts a simple permanent marker, and uses a servo to push the holder away from the paper for retraction, rather than moving the pen itself. Control of the system is via the Makelangelo firmware, an open-source effort capable of driving a wide variety of CNC motion systems.

The final result is a simple plotter using readily available parts that can reliably plot large graphics on a piece of A1 paper. We’re particularly impressed by the clean, continuous lines it produces – testament to a sound mechanical design.

We see plenty of plotters around these parts; even rotary types that can draw on curves. Video after the break.

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Listening To Long Forgotten Voices: An Optical Audio Decoder For 16 Mm Film

January 2, 2021 by 21 Comments

Like many of us, [Emily] found herself on COVID-19 lockdown over the summer. To make the most of her time in isolation, she put together an optical audio decoder for old 16 mm film, built using modern components and a bit of 3D printing.

It all started with a broken 16 mm projector that [Emily] got from a friend. After repairing and testing the projector with a roll of film bought at a flea market, she discovered that the film contained an audio track that her projector couldn’t play. The audio track is encoded as a translucent strip with varying width, and when a mask with a narrow slit is placed over the top it modulates the amount of light that can pass through to a light sensor connected to speakers via an amplifier.

[Emily] used a pair of razor blades mounted to a 3D printed bracket to create the mask, and a TI OPT101 light sensor together with a light source to decode the optical signal. She tried to use a photoresistor and a discrete photodiode, but neither had the required sensitivity. She built a frame with adjustable positions for an idler pulley and the optical reader unit, an electronics box on one end for the electronic components, and another pulley attached to a stepper motor to cycle a short loop of the film.

Most of the projects we see involving film these days are for creating digital copies. You can digitize your old 35 mm photo film using a Raspberry Pi, some Lego pieces, and a DSLR camera, or do the same for 8 mm film with a 3D printed rig. Continue reading “Listening To Long Forgotten Voices: An Optical Audio Decoder For 16 Mm Film” →

Checking In On Low-Cost CNC Machines

January 2, 2021 by 43 Comments

Low cost 3D printers have come a long way in the last few years, but have entry-level CNC machines improved by the same leaps and bounds? That’s what [ModBot] recently set out to find. Despite getting burned pretty badly on a cheap CNC a few years back, he decided to try again with a sub $400 machine from FoxAlien. You can see his full review after the break.

The machine looks very similar to other generic CNC machines you see under many brand names, sometimes for a good bit less. The 3018 number is a giveaway that the work area is 30×18 cm and a quick search pulled up several similar machines for just a bit more than $200. The FoxAlien did have a few nice features, though. It has a good-looking build guide and an acrylic box to keep down the shaving debris in your shop. There are also some other nice touches like a Z-axis probe and end stops. If you add those items to the cut-rate 3018 machines, the FoxAlien machine is pretty price competitive when you buy it from the vendor’s website. The Amazon page in the video shows $350 which is a bit more expensive but does include shipping.

As with most of these cheap CNC machines, one could argue that it’s more of an engraver than a full mill. But on the plus side, you can mount other tools and spindles to get different results. You can even turn one of these into a diode laser cutter, but you might be better off with something purpose-built unless you think you’ll want to switch back and forth often.

This reminded us of a CNC we’ve used a lot, the LinkSprite. It does fine for about the same price but we are jealous of the enclosure. Of course, half the fun of owning something like this is hacking it and there are plenty of upgrades for these cheap machines.

Mattress-made MIDI Device Plays Exotic Tunes

January 2, 2021 by 5 Comments

Ever heard of a handpan? If not, imagine a steel drum turned inside out, and in case that doesn’t help either, just think of a big metal pan you play music with by tapping your hands on its differently pitched tone fields. But as with pretty much any musical instrument, the people around you may not appreciate your enthusiasm to practice playing it at any time of the day, and being an acoustic instrument, it gets difficult to just plug in your headphones. Good news for the aspiring practitioners of Caribbean music though, as [Deepsoul77] created a MIDI version of this rather young and exotic instrument.

Using the foam salvaged from an old mattress as the core of the handpan, [Deepsoul77] cut a couple of plywood pads as tone fields that will be attached to the foam. Each plywood tone field will then have a piezo element mounted in between to pick up the hand tapping. Picking up the tapping itself and turning it into MIDI signals is then handled by an Alesis trigger interface, which is something you would usually find in electronic drums. From here on forward, it all becomes just a simple USB MIDI device, with all the perks that brings along — like headphone usage or changing MIDI instruments to make anything sound like a trumpet.

Turning what’s essentially a drum kit into a melodic instrument is definitely neat, and to no surprise, we’ve also seen the actual home made drum kit with piezo elements. Of course, using MIDI to quiet down an acoustic instrument isn’t new either, though it also works somewhat the other way around. But then again, it doesn’t always have to be MIDI either.

A Vintage Flip Clock Gets Some Modern Love

January 2, 2021 by 6 Comments

There are multiple reasons why we like [iSax]’s rebuild of a Bodet flip clock from the early 1980s. First there’s the retro charm of the timepiece itself, then the electronics used to drive it, its electromechanical month length and leap year system, and finally because here is a maker lucky enough to have a beautiful tabby cat to share the workbench with.

For those of you unfamiliar with a flip clock, these devices have their digits as a series of hinged cards on a central rotor, with each one being exposed in turn as the rotor turns. This one is part of a distributed clock system in which the clients receive a 1 Hz pulse from a central time server to drive their motors, something easily replicated with an Arduino and an H-bridge. Particularly fascinating though is the month length mechanism, part of the calendar rotor system, it has a small DC motor that is engaged to advance the days automatically by whichever number as part of the month transition. Originally this was powered by a couple of AA batteries, which have now been replaced with a small DC to DC converter. You can see it in action in the video below the break.

With or without tabby cats, we see quite a few projects featuring them. If you can’t find one, you can always make your own.

Continue reading “A Vintage Flip Clock Gets Some Modern Love” →