Empanada Becomes Impractical, Delicious Synth

Vegemite is an Australian staple – a rich, protein-filled sandwich spread with a strong salty flavor. It serves as a great way to add a little umami to any dish, which is the hottest open secret in Australian cuisine this decade. It also works as a servicable conductive paint, which [Alex] used to make this baked good into a musical device.

The basis of the device is a basic audio example sketch running on an Adafruit Circuit Playground Express. The code was tweaked to play a 7-note C major scale. The PCB was then attached to the empanada with toothpicks through each pad, with the baked good itself seemingly connected to the ground plane. The toothpicks through the pads were then coated with Vegemite, and another toothpick treated the same way and used as a stylus. By touching the toothpick to the empanada and one of the pads, the circuit is made, and a note is played.

It’s an impractical way to go about musical performance, sure. But it is an effective demonstration of foodstuffs used in electronics. Calvin Harris did much the same back in 2009, albeit with humans substituting for the delicious pastry. Video after the break.

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Casein, Cello, Carrotinet, And Copper Oxide, Science Grab Bag

One of our favorite turnips, oops, citizen scientists [The Thought Emporium], has released his second Grab Bag video which can also be seen after the break. [The Thought Emporium] dips into a lot of different disciplines as most of us are prone to do. Maybe one of his passions will get your creative juices flowing and inspire your next project. Or maybe it will convince some clever folks to take better notes so they can share with the rest of the world.

Have you ever read a recipe and thought, “What if I did the complete opposite?” In chemistry lab books that’s frowned upon but it worked for the Reverse Crystal Garden. Casein proteins make cheese, glue, paint, and more so [The Thought Emporium] gave us a great resource for making our own and demonstrated a flexible conductive gel made from that resource. Since high school, [The Thought Emporium] has learned considerably more about acoustics and style as evidence by his updated cello. Maybe pulling old projects out of the closet and giving them the benefit of experience could revitalize some of our forgotten endeavors.

If any of these subjects whet your whistle, consider growing gorgeous metal crystals, mixing up some conductive paint or learning the magnetic cello. Remember to keep your lab journal tidy and share on Hackday.io.

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DOTS Uses Paint To Control Raspberry Pi 2

Two tables down from us at SXSW Create the Raspberry Pi foundation had a steady stream of kids playing Minecraft on Raspberry Pi, and picking up paint brushes. The painting activity was driven by a board they spun for the event that used conductive paint to control the Raspberry Pi 2.

rear-of-the-raspberry-pi-2The board uses the HAT form factor which it a fancy name for a shield (also a clever one as it stands for “Hardware Attached on Top”). You can see the back side of the board in this image. It utilizes an extremely low-profile surface mount pin socket.

The front side exposes several circular pads of copper which build up a “connect-the-dots” game that is played by painting conductive ink on the surface. This results in an airplane being pained on the board, as well as displayed on the computer. There is a set of pads that allow the user to select what color is painted on the monitor.

We like this as a different approach to education. Kids are more than used to tapping on a touchscreen, clicking a mouse, or pounding a keyboard. But conductive ink provides several learning opportunities; the paint simply connects the inner circle with the outer circle; one of these circles is the same on every single dot (ground); anything that connects these two parts of the dot together will result in input for the computer. Great stuff!

The foundation is taking the boards to Maker Faire Bay Area next month so stop by to see these in action. You can read about the production process for the DOTS board on the Raspberry Pi website. They’re giving away a few boards to software developers who want contribute to the project. And our video interview with [Matt Richardson] is found after the break.

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Play Music With Your Painting Using Teensy

[sab-art], a collaboration between [Sophia Brueckner] and [Eric Rosenbaum], has created a touch-sensitive musical painting. Initially, basic acrylic paint is used for the majority of the canvas. Once that is dry, conductive paint is used to make the shapes that will be used for the capacitive touch sensing. As an added step to increase the robustness, nails are hammered through each painted shape and connected with wiring in the back of the painting. These wires are then connected to the inputs of a Teensy++ 2.0, using Arduino code based on MaKey MaKey to output MIDI. The MIDI is then sent to a Mac Mini which then synthesizes the sound using Ableton Live.  Any MIDI-processing software would work, though. For this particular painting, external speakers are used, but incorporating speakers into your own composition is certainly possible.

A nice aspect of this project is that it can be as simple or as complex as you choose. Multiple conductive shapes can be connected through the back to the same Teensy input so that they play the same sound. While [sab-art] went with a more abstract look, this can be used with any style. Imagine taking a painting of Dogs Playing Poker and having each dog bark in its respective breed’s manner when you touch it, or having spaceships make “pew pew” noises. For a truly meta moment, an interactive MIDI painting of a MIDI keyboard would be sublime. [sab-art] is refining the process with each new painting, so even more imaginative musical works of art are on the horizon. We can’t wait to see and hear them!

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DIY Conductive Paint For All Your Wearable Needs

DIY Conductive Paint

Conductive ink or paint is lots of fun. It opens up tons of possibilities for flexible and unique circuits — unfortunately, it’s pretty expensive. [Brian McEvoy] shows us how to make your own for cheap, and it works great!

He started trying to formulate his own recipe after playing with other Instructable guides and commercially available paint, and what he found is it’s really not that complex! Graphite powder, acrylic paint, and a jar with an airtight seal — seriously, it’s that simple! But, like any engineer worth their salt (he calls himself the 24 Hour Engineer), he had to do some tests to compare his formula.

In a detailed experiment he compares his formula to the commercially available Wire Glue, and two other recipes using Elmer’s Glue-All and graphite, and Titebond III with graphite. The results? Acrylic paint and graphite produce the most conductive material — and the cheapest!

Now that you can make conductive ink, why not 3D print a circuit stamp to make your very own SMD circuit board!