Catarina Mota Founder OpenMaterials.org


Osborn: Could you explain what Physical Computing  is?

Mota: Physical Computing  at ITP is the intro to electronics class. Many peo- ple in the program do not have a background  in electrical engineering, so the class focuses on teaching students how to work with electronics,  program  a microcontroller, etc. The Tech Crafts  class I taught, which could be taken after physical computing, focused not so much on traditional electronics materials and engineering platforms, like breadboards, perf boards, PCBs,3 but on mak- ing your own. We made our own sensors, we made our own resistors, things like that, out of mostly raw materials, both smart and traditional. The idea was to take electronics out of the box and off the PCB. By understanding how each of the components works, you have a lot more freedom to create. For example, there was a group  of students who wanted to make  a rug that reacts when someone steps on it and decided to use pressure sensors since that's the most common  solution  available off the shelf. The pressure sensors were about an inch wide, so they had to wire a bunch  of them together to cover the entire surface of the rug, which makes the process more complicated and expensive. Using smart materials, such as conductive  ink or conductive 3Printed circuit boards. fabrics, you can just make a single pressure sensor yourself  in any shape. So that’s what the class focused on. I am not a materials scientist. I knew nothing about this. I learned on my own and from other people. I learned  a lot from Hannah Perner-Wilson, Jie Qi, and Leah Buechley. There  are still only a hand- ful of us working with these materials in Europe and in the US that I know of. But the number of individuals  is growing  as well as the number of universities. There are a couple of universities with materials science departments  that are starting to focus more on simpler ways of making and using materials. They are publishing simpler formulas that don’t require specialized equipment  so they can enable makers. I did see a huge growth  in terms of interest and activ- ity in this area in the four years since we started OpenMaterials.

Osborn: Can you give me a couple  examples of materials that you have on OpenMaterials? Maybe the ones that you think are interesting or popular?

Mota: One of the most popular is conductive ink, which is basically a black ink infused with graphite or some other sort of conductive particles. Conductive ink used to be really expensive because it was made of silver, so it was not accessible to most people. But now that they’re making it with graphite, it’s pretty cheap. People started  using it first to make traces in circuits. Personally, I find that that is not necessarily the best use for the material, because copper is so much better for that purpose. In my opinion conductive ink is really good to make sensors in any shape that you want. You can apply it to any material. You can paint an area and turn it into a capacitive  sensor, for example. Or you can make a touch sensor on a book without a lot of hardware.

Osborn: Turn surfaces into sensors. So when I touch the conductive ink it would  sense the presence of my hand and the object can react in some way?

Mota: Exactly. That’s one type of sensor that you can make with conductive ink. Another great property of this material that can be used for sensors is its resistance. It’s significantly more resistant than copper, nickel, and other metals that we normally  use as conductors. What that means is, if you paint a line of conductive paint, the resistance on one end is going to be different from the resistance on the other end because it gets increasingly more resistive. A lot of the sensors that we use are based on variable resistance. In this case, the whole material is the variable resistor so you can use it to make a potentiom- eter. I’ve used conductive ink to paint a circular  sensor on paper in order to control the volume of a piezo buzzer for example.

Osborn: I don’t know if I saw this on your site recently, but I saw a speaker somebody made out of a Post-it note and some copper  spirals. It was pretty interesting. They just had a magnet  and the Post-it note and they made  a speaker, which  was a pretty interesting way to learn about speakers.

Mota: That is the kind of work that Leah Buechley and Hannah Perner-Wilson, who was Leah's student at the High-Low Tech Group at MIT several years ago, are doing. They explore the intersection of craft and technology  and came up with many interesting  systems that have inspired  the rest of us. The Pulp-Based Computing4 group, led by Marcelo Coelho, is another group work- ing on this topic at MIT. They mix paper and crafts materials with hardware. A few years ago, Marcelo wrote a paper about making speakers. And based on that, Hannah Perner-Wilson created  a series of handmade speakers that use paper, fabric and magnets. If you go to Kit-of-No-Parts,5  you’ll see a lot of really interesting experiments  in which she deconstructs  electronics components and hardware, and then builds them from the ground up with unusual materials.

Osborn: At some point, you did a TED talk. Not just anyone gets to come in and talk at TED. I’m interested to hear about that experience and how you got invited. What was that experience like for you?

Mota: What happened  was a bit of a network effect, I think. I didn’t know this at the time, but I later reconstructed it. I did a talk, a materials  run-through, at the Open Hardware  Summit a couple of years ago. And there was someone there who was an advisor  to the TED Fellows Program. So after that I got an e-mail from the TED Fellows Program saying, “We have this program. You should consider applying.” At the time, I didn’t really know what the program was, only that they bring fellows to one TED conference. So I thought, “Wow, cool. Free TED conference.” I ended up applying at the very last minute of the deadline and didn't think about it again. And then I went through the process. It’s a couple of interviews and references, things like that. A lot of people get super nervous with those interviews. At the time, I didn’t because I had no idea what I was applying for.

Osborn: Nice. You were just cool as a cat.

Mota: It was just,“Oh, you know, no pressure.” Eventually, I got the fellowship and with the fellowship comes the possibility of giving one talk. All the new fellows give one talk before the mainTED program begins. That’s already pretty nerve-racking. But then I got a call from the curator of TED Global—there are two TED conferences: one here in the US and another elsewhere in the world—with an invite to also give a main  stage talk. So that’s how that happened. I was flabbergasted. It was very intense, because for this one conference, I gave two talks on two consecutive  days and TED conferences require months of preparations. In addition to that, I also participated  in a parallel  showcase, a sort of exhibition area at the conference venue.

Osborn: And then you went home and slept for days I imagine. That would be exhausting.

Mota: Right. It was a very, very, very intense week there. I think there are around six hundred attendees at TED conferences. And, when you give a talk at a conference, people will know who you are afterward and know what you do, so many will come talk to you about that topic. I think I must have talked to hundreds of people, which is not something I'm used to. It was amazing and very much  a blur. That was it for the TED conference, but TED fellowships are sort of for life. We only get to go to a conference  once, the first year, but the fellowship doesn't end there. It’s an amazing network,  an amazing, amaz- ing network. There are, I don’t know, three or four hundred fellows from all areas—scientists, artists, engineers, programmers, everything. So, basically, it’s  this worldwide network of people who really like each other and are constantly collaborating and exchanging information.  Given what I know now, if I was applying for the fellowship today, I would be very nervous  because I would be afraid of not getting it.Speaking of networks and exchanging information,going back to OpenMaterials for a second,  I just wanted to mention my criteria for selecting materials because that's very important to me. First, they have to be commercially available, so other people can buy them. I have no interest in working with a material that others can’t get. Then, they have to be available in quantities and at prices that are accessible to most  people. Finally, they can’t require special- ized equipment. So my criteria  are all based on availability to others.