Last summer a few of us at NYC Resistor made the JelTone, a jello-based toy piano that can be eaten and played. Now, Marianne Cauvard and Raphael Pluvinage created the beautiful Noisy Jelly, a kit to make your own musical instrument out of agar.

With this noisy chemistry lab, the gamer will create his own jelly with water and a few grams of agar agar powder. After added different color, the mix is then pour in the molds. 10 min later, the jelly shape can then be placed on the game board, and by touching the shape, the gamer will activate different sounds.

Technically, the game board is a capacitive sensor, and the variations of the shape and their salt concentration, the distance and the strength of the finger contact are detected and transform into an audio signal.

This object aims to demonstrate that electronic can have a new aesthetic, and be envisaged as a malleable material, which has to be manipulated and experimented.

(via Trammel Hudson)

Jordan Bunker from Pumping Station: One has been making his own conductive ink based on a paper written by researchers at the UIUC Materials Research Laboratory. This technique uses easily obtainable materials and tools, and can be reproduced at most hackerspaces. For now, the ink doesn’t work on porous materials, such as a paper, and plastic and glass substrates must be etched first, but Jordan is working on addressing these issues and will keep posting developments. In the meantime he worked out a pretty simple process to manufacture conductive ink!

This ink seems to address many of the problems that other inks have. It’s particle free (won’t clog print heads!), is easy to make, and anneals to the conductivity of bulk silver at only 90 degrees Centigrade (194 degrees Fahrenheit).

Check out his description of the process on the video above and then head over to his website for a detailed tutorial on how to make your own conductive ink. Bonus points for making your own vortex mixer based on onetruecathal’s video tutorial.

University of Illinois researchers explain how they make their conductive ink on this step-by-step tutorial.

(via Boing Boing)

The Resistor JelTone is an edible toy piano created by NYC Resistor members Ranjit Bhatnagar, Astrida Valigorsky, Mimi Hui and myself for the Jello Mold Competition.

As part of our experiments we realized that jello and fruit, which contain a lot of water, are conductive. Embedded in each jello/fruit key is a sterling silver pin (food safe) connected to an Arduino microcontroller underneath the piano’s base. Below the piano’s case is another sterling silver pin. With this setup, the JelTone can either be played with a metal utensil connected to the Arduino, gloves enhanced with conductive thread, or bare hands by touching both a key and the piano’s case.

If you’d like to make your own, you can get the project files, code and instructions from Thingiverse.

The JelTone (in its jello and fruit versions) was exhibited and eaten at the 2011 Solid Sound Festival (Mass MoCA), the Jello Mold Competition (where it was awarded the creativity prize), the NY Hall of Science “Dead or Alive” Halloween Festivities, the Toy Piano Festival, and the Guthman Musical Instrument Competition.

A stellar performance by Ranjit at the
Guthman Musical Instrument Competition

A master pianist plays the Jeltone at the NY Hall of Science

The Jeltone at the 2011 Solid Sound Festival

The Jeltone at the Jello Mold Competition

LED Dragon Kite by Jie Qi

Jie Qi, from MIT’s High-Low Tech group, posted a couple really nice tutorials on how to combine paper, electronics and smart materials to create beautiful objects.

The LED dragon kite: http://hlt.media.mit.edu/?p=1414
SMA origami crane: http://hlt.media.mit.edu/?p=1448

Heat Reactive Materials
Heat reactive materials change state, shape and/or color when exposed to temperatures above ambient. Naturally, many materials change state, eg. melt, at high temperatures. What’s special about some of them that their state, shape and/or color can be altered at relatively low temperatures (provided through hot water, body heat, hair dryers, ambient heaters, ovens, or just a hot summer day), making them easy to use and suitable for DIY projects. In this post I’ll go over polymorph, shape memory polymers and heat-shrink materials.

:: polymorph
:: shape memory polymers
:: heat-shrink (tubing and thread)
:: suppliers

Polymorph, aka polycaprolactone, is a biodegradable polyester with a low melting point of around 60ºC (140ºF). It can be heated with just hot water then molded by hand or cast. Once it cools to room temperature, polymorph becomes a hard, nylon-like plastic, which can be reheated and reshaped any number of times.

“Molding a Handle” tutorial by Inventables

Polymorph is extremely easy to use. Start by filling a container with very hot water. Add some polymorph granules and wait until they turn clear and cluster together. At this point, the polymorph is ready to be shaped. Scoop it out of the hot water bath (with tongs or something like that) and shape it by hand or press it into a mold (see video above). Once molded let the polymorph cool completely - you’ll know it’s ready when it turns back to solid white. You can also melt polymorph with a hair dryer or a heat gun, but avoid using flames (such as a lighter) as this will blacken the material. Powdered pigments such as this one can be used to color polymorph.

ECCEROBOT with polymorph ‘bones’ (images by France Cadet)

Shape Memory Polymers (SMP) can be re-shaped when exposed to heat and will retain this new shape after cooling down. But once exposed again to the change-over temperature the polymer will revert back to its original shape. The physical properties, behavior and change-over temperature vary greatly from SMP to SMP. According to Wikipedia:

SMPs can retain two or sometimes three shapes, and the transition between those is induced by temperature. In addition to temperature change, the shape change of SMPs can also be triggered by an electric or magnetic field, light or solution. As well as polymers in general, SMPs also cover a wide property-range from stable to biodegradable, from soft to hard, and from elastic to rigid, depending on the structural units that constitute the SMP. SMPs include thermoplastic and thermoset (covalently cross-linked) polymeric materials.

Shape memory plastic sheet (image by Inventables)

Shape memory polymers have been finding several industrial applications, such as CRG’s Smart Mandrels:

When heated above the transition temperature, the mandrel becomes elastic and can easily be molded into a desired shape. Once cooled, the material will become rigid and retain the new shape. The mandrel can then be filament wound and the resulting part cured on the mandrel. Heating the mandrel above its transition temperature after the part is cured makes the mandrel elastic again and easily extractable from the part. Because of the mandrel’s shape memory properties, it can be returned to its original tubular shape and reused.

Heat-Shrink Tubing is manufactured from a thermoplastic (such as nylon or polyolefin) which shrinks when exposed to heat. It’s used mostly to insulate wires, connections, joints and terminals in electrical engineering. According to Wikipedia:

According to the exact material used, there are two ways that heat shrink may work. If the material contains many monomers, then when the tubing is heated the monomers polymerise. This increases the density of the material as the monomers become bonded together, therefore taking up less space. Accordingly, the volume of the material shrinks. Heat shrink can also be expansion-based. This process involves producing the tubing as normal, heating it to just above the polymer’s crystalline melting point and mechanically stretching the tubing (often by inflating it with a gas); finally, it is rapidly cooled. Later, when heated, the tubing will relax back to the un-expanded size. The material is often cross-linked through the use of electron beams, peroxides, or moisture. This cross-linking helps to make the tubing maintain its shape, both before and after shrinking. For external use, heat shrink tubing often has a UV stabilizer added.

Heat-shrink tubing

To use simply run the wires, or whatever you wish to enclose/insulate, through the heat-shrink tubing and then apply heat with a heat-gun or lighter, this will cause the tubing to shrink and mold itself around the wires. This shape change is irreversible, i.e. once shrank it’s not possible to revert the tubing back to its original shape.

Heat-Shrink Thread, which is made of polyester, looks and sews just like regular thread but when exposed to heat (176ºC/350ºF) shrinks 10 to 30% (depending on composition). To use, start by stitching normally and then apply heat with a household iron. See Erica’s Craft and Sewing Center for detailed instructions (clicking on the image of the thread will open a PDF with instructions)

Heat-shrink thread and textile perfboard (image by Plug & Wear)

Suppliers
Erica’s Craft and Sewing Center (US): heat-shrink thread
Inventables (US) :: shape memory polymers (sheets and strips), hand moldable plastic (aka polymorph)
Mindsets (UK): polymorph, shape memory polymer
Plug & Wear (Italy): heat-shrink thread
* Polymorph and heat-shrink tubing are common crafts and electronics materials and can be found in a variety of online stores.

Share your knowledge
If you’d like to contribute content or corrections regarding heat reactive polymers, please use the comment form below.

>> about the materials 101 series.

Heat Reactive Materials
Heat reactive materials change state, shape and/or color when exposed to temperatures above ambient. Naturally, many materials change shape, eg. melt, at high temperatures. What’s special about some of them is that their state, shape and/or color can be altered at relatively low temperatures (provided through hot water, body heat, hair dryers, ambient heaters, ovens, or just a hot summer day), making them easy to use and suitable for DIY projects. In this post I’ll go over thermochromic pigments and a few materials they have been incorporated into, namely paint, fabric, film and glass.

Thermochromic Pigments change color when exposed to heat and turn back to their original color when the temperature drops again. According to TEP:

Most thermochromic materials are based on liquid crystal technology. At specific temperatures the liquid crystals re-orientate to produce an apparent change of colour. The liquid crystal material itself is micro-encapsulated - i.e., contained within microscopic spherical capsules typically just 10 microns in diameter. Billions of these capsules are mixed with a suitable base to make thermochromic printing ink or, for example, plastics destined for injection molding.

These pigments can be mixed with an acrylic base or screen printing ink. At room temperature the pigment appears in its original color, but at temperatures between 27° and 30°C (80° to 86°F) this color disappears, eg, if a black pigment is applied to a white surface, the surface turns from black to white at the change-over temperature. When mixed with an acrylic base each pigment will turn instead into the color of the acrylic base or color blender, eg., if a blue pigment is mixed with a yellow acrylic base the resulting color will be green, but at the change-over temperature the blue will disappear and the green will turn into yellow. The ratio of acrylic base to coloring pigment depends entirely on the application and density of color required. For a detailed explanation of the functioning and applications of thermochromic pigments see the TEP Smart Colors info sheet (PDF) and this little demo animation.

Shi Yuan’s thermochromic wallpaper

Temperature-Sensitive Glass results from the application of thermochromic pigments to glass tiles which change color based on ambient, body or water temperature:

The textured glass surface layer protects and highlights the color-change film on the tile. The base color of the tile can match almost any color, and the temperature change point can be fit to the user’s environment and requirements. The dynamic color change begins at the selected activation temperature and shimmers through three phases, one with each 6–10° rise in temperature. Once the temperature peak is passed, the base color returns and remains the same until the temperature drops.
(source: Inventables)

Temperature-sensitive glass tile (image by Inventables)

Thermochromic Film has adhesive on one side and thermochromic ink on the other. The film is normally black but changes to bright green/blue at temperatures between 29.4 and 33°C (84º - 91º F). Due to its low change-over temperatures, touching a piece of thermochromic film for a few seconds will cause the contact area to change color - it can also be used with nichrome or any other heat source.

Thermochromic film (image by Mindsets)

Suppliers
Body Faders (US) :: thermochromic fabric
Inventables (US) :: thermochromic fabric, thermochromic film, temperature-sensitive glass tiles
Mindsets (UK): thermochromic pigments, thermochromic film
Paint with Pearl (US) :: thermochromic pigment powder

Share your knowledge
If you’d like to contribute content or corrections regarding thermochromic materials, please use the comment form below.

>> about the materials 101 series.

The Open Hardware Summit (OHS) invites submissions for the second annual summit, to be held on September 15, 2011 in New York City. The Open Hardware Summit is a venue to present, discuss, and learn about open hardware of all kinds. The summit examines open hardware and its relation to other issues, such as software, design, business, and law. We are seeking submissions for talks, breakout sessions, and demos from individuals and groups working with open hardware and related areas. Submissions are due by June 24, 2011. Notification of accepted proposals will happen by August 1st.

Since the first Open Hardware Summit in 2010, we have seen the open hardware movement continue to flourish. The Open-Source Hardware Definition was announced, the OSHW logo was selected by a popular vote, an open source oil spill cleaning robot got more than $33,000 in crowd funding, Google adopted the open hardware movement’s biggest success story, Arduino, as its platform and our very own keynote speaker, Limor Fried, was featured on the front page of Wired Magazine – to name a few. Needless to say, open hardware is getting BIG.

Head over to the Open Hardware Summit website for more details on submissions.

Empa’s EAP propelled airship with Dielectric Elastomer (DE) actuators as muscles.

SketchChair, a project by Tiago Rorke and Greg Saul of Diatom, is an “open-source software tool that allows anyone to easily design and build their own digitally fabricated furniture:”

The SketchChair software allows anybody to take part in the process of designing and building their own chairs. The program lets users design chairs using a simple 2d drawing interface, automatically generating the structure of a chair and testing its stability. Users can simulate sitting on a chair with a customizable figure of themselves, in order to test and refine the chair to ensure it will comfortably support them.

The software automatically generates cutting profiles for the chairs, which can then be used to make physical SketchChairs. Using a cnc router, laser cutter or paper cutter, these parts can be cut from any suitable flat sheet material, and then easily assembled by hand.

We have launched SketchChair as a Kickstarter campaign, to try and raise funds to complete the software and release the source code, and to start building an online community of people creating, sharing and editing designs.