Clemens Valens, caught up with Peter Lomas, hardware designer for the Raspberry Pi single-board computer, earlier this year at the Embedded World 2013 trade show in Nuremberg, Germany. The Lomas interview provided a one-year update on the rapid growth of interest in the Raspberry Pi since April 2012 interview with Eben Upton, one of the founders and trustees of the Raspberry Pi Foundation. The UK-based charitable foundation developed the inexpensive, credit card-sized computer to encourage the study of basic computer science in schools. In early 2012, the Raspberry Pi’s first production batches were arriving. Since then, more than 1 million boards have been sold.
CLEMENS: Raspberry Pi, the phenomena. It is quite amazing what happened.
PETER: It is, and lots of people keep asking me, why has Raspberry Pi done what it has done, what makes it different? I think it’s something we’ve really been trying to grasp. The first thing that happened with Raspberry Pi, which I think is important, is that we had one of our very first prototypes on a UK blog for one of the BBC correspondents, Rory Cellan-Jones, and they made a little video, a YouTube video, and that got 600,000 hits. So I guess that if you look at it from one aspect, that created a viral marketing, a very viral marketing campaign for Raspberry Pi. The other I think, the name, Raspberry Pi was key. And the logo that Paul Beach did for us is absolutely key because it has become iconic.
CLEMENS: Yes, it’s very recognizable.
PETER: Very recognizable. If I show you that, you know exactly what it is, in the electronics circle. So I think the brand has been very important. But you know, we shouldn’t forget the amount of work that Liz Upton’s been doing with the blogs and on our website, keeping people informed about what we’re doing. Then, I think we’ve got the fact we are a charity… that we are focused on the education of computing and electronics and that’s our motive—not actually to make boards and to make money except to fund the foundation.
CLEMENS: I looked at the Raspberry Pi website, and it doesn’t look easy to me. You target education, children, and on the website it’s hard to find what Raspberry Pi exactly is. It’s not really explained. You have to know it. There are several distributions, so you have to know Linux and you have to program in Python.
PETER: Well, that’s true and, in a weird way, that’s part of its success, because you actually have to be active. In order to do something with Pi, you can’t just get it out of a shiny box, put it on the desk and press “on.” You have to do some mental work. You have to figure some things out. Now, I actually think that there’s a bit of a benefit there, because when it actually works, you have some achievement. You’ve done something. Not “we’ve done something.” You’ve done it personally, and there is a gratification from doing it.
CLEMENS: But it’s not the easiest platform.
PETER: No, but with our educational proposition, the whole object now is to package that up in easier-to-use bundles. We can make the SD card boot straight to Scratch (a website project and simple programming language developed at the Massachusetts Institute of Technology Media Lab), so Linux becomes temporarily invisible, and there’s a set of worksheets and instructions. But we’re never going to take away, hopefully, the fact that you have to put your wires in, and I do think that is part of the importance and the attraction of it.
CLEMENS: Because of all these layers of complexity and having to program it in English (Python is in English), for the non-English population it is yet another hurdle. That’s why Arduino was so successful; they made the programming really easy. They had cheap hardware but also a way to easily program it.
PETER: There’s no doubt Arduino is a brilliant product. You are right, it enables people to get to what I call “Hello World” very easily. But, in fact, on a Raspberry Pi, after you’ve made those connections and plugged the card in, you can get to an equivalent “Hello World.” But ours is the Scratch cat. Once you’ve moved the Scratch cat, you can go in a few different directions: you can move it some more, or you can use Scratch with an I/O interface to make an LED light up or you can press a button to make the Scratch cat move. There are endless directions you can go. I’ve found, and I think Eben has similarly experienced, that kids just get it. As long as you don’t make it too complicated, the kids just get it. It’s the adults who have more problems.
CLEMENS: I saw that there are at least three different distributions for the boards. So what are the differences between the three? Why isn’t there just one?
PETER: Well, they all offer subtly different features. The whole idea was to make Raspberry Pi as an undergraduate tool. You give it to Cambridge University, hopefully Manchester University, and undergraduates can view the science before they start it. They have the summer. They can work on it, come back, and say: “Look, I did this on this board.” That’s where it all started.
CLEMENS: OK. So, you were already on quite a high level.
PETER: Well we were on a high level, that’s true. We were on a high level, so Scratch wouldn’t have been on the agenda. It was really just Python—that’s actually where the Pi comes from.
What has really happened is that we’ve developed this community and this ecosystem around Pi. So we have to be able to support the, if you like, “different roots” of people wanting to use Pi. Now we’ve got the RISC OS that you can use. And people are even doing bare-metal programming. If we just gave one distribution, I guess we’re closing it up. I fully approve of having different distributions.
CLEMENS: From the website, it’s not clear to me what is different in these distributions. For the first one, it is written: “If you’re just starting out.”
PETER: I think maybe we do need to put some more material in there to explain to people the difference. I have to explain: I’m the hardware guy. I’m the guy who sat there connecting the tracks up, connecting the components up. My expertise with the operating systems, with the distributions that we have, is really limited to the graphical interface because that’s what I use day in, day out.
CLEMENS: Once you have chosen your distribution and you want to control an LED, you have to open a driver or something, I suppose?
PETER: Well, you’ve got the library; you just have to make a library call. Again, it’s not easy. You have to go and find the libraries and you have to download them. Which is where things such as the Pi-Face (add-on board) come in, because that comes with an interactive library that will go onto Scratch. And you’ve got the Gertboard (another extension board) and that comes with the libraries to drive it and some tutorial examples and then you can wind that back to just the bare metal interface on the GPIOs.
CLEMENS: So the simplicity is now coming from the add-on boards?
PETER: Some of the add-on boards can make it simpler, where they give you the switches and they give you the LEDs. You don’t need to do any wiring. My view is that I’m trying to make it like an onion: You can start with the surface and you can do something, and then you can peel away the layers. The more interested you get, the more layers you can peel away and the more different directions you can go (in what you do with it). You must have seen the diverse things that can be done.
CLEMENS: I’ve looked at some projects. I was surprised by the number of media centers. That’s how RS Components (which distributes the Raspberry Pi) is promoting the board. Aren’t you disappointed with that? It seems to be, for a lot of people, a cheap platform to do a Linux application on. They just want to have a media center.
PETER: I know exactly what you mean. And I suppose I should be disappointed that some people buy it, they make it into a media center, and that’s all it does. But I think if only 5% or 10% of those people who make it into a media center will think: “Well, that was easy, maybe I’ll get another and see if I can do something else with it,” then it’s a success.
CLEMENS: It would be an enabler.
PETER: Getting the technology in front of people is the first problem. Getting the “Hello World” so they’ve got a sense of achievement is the second problem. Then turning them over from doing that to “Okay, well what if I try and do this?” then that’s Nirvana. Certainly for the kids that’s crucial, because we’re changing them from doing what they’re told, to start doing things that they think they might be able to do—and trying it. That makes them into engineers.
CLEMENS: Let’s move on to the board’s hardware.
CLEMENS: So, you chose a Broadcom processor. Because Eben worked at Broadcom?
PETER: He still works within Broadcom. It would be hard for me to argue that that wasn’t an influence on the decision, because Eben said: “Oh look, here’s the bright shiny chip. It can do all the things that we want, why wouldn’t we use it?” The decision we made is we nailed our credentials and our reputations to the website by saying it will cost $35—it will cost $25 for the basic one. And there was no way on Earth any of us were going to go back on that… We had a spreadsheet, the basic numbers looked plausible, we just had to do a lot of work to chop it down—to hone it, to get it tight so it would actually meet the prices. So, I think if we’d gone another way, like maybe with Samsung, that would have blown the budget.
CLEMENS: Did Broadcom help in any way to make this possible?
PETER: Every semiconductor manufacturer helped the project by making the chips available. Also, the price point of the chips is important. I think some of the people who helped us took an educated gamble and gave us good pricing from day one. Because the big problem you get with trying to bootstrap any project, is that if you don’t know what your volume is going to be. You have to be conservative.
So, initially, we priced for a thousand boards, but quickly we priced for 20,000 boards, but nowhere in our wildest dreams did we think we were going to get to a 200,000-board requirement on launch day and be so tantalizingly close to selling a million after our first year. So that’s helped in a lot of ways, because obviously it’s driven the price of all the components down. I’m not going to pretend it doesn’t please the vendors of the components that had faith in us from day one, because they’ve obviously made some money out of it.
We always had the rationale that we had to have a sustainable model where the foundation, our community that is buying the boards, and our suppliers were all making a living and could feed themselves. It would have been a total disaster if someone such as Broadcom had said: “Tell you what guys, let’s give you the processors. We’ll give you the first 20,000.” And so, we could have provided all sorts of extra bells and whistles to the design. Then, when we would have sold these 20,000 boards, we’re going to raise the price of everything by $12. That would’ve been the end of Raspberry Pi.
CLEMENS: If Eben and the others had not worked for Broadcom…
PETER: Would we have used a different chip? Well, I sort of speculated about this and I went around and had a look and, at the time for the price point, we couldn’t find anything that would’ve met our requirements as well as that chip. So I was comfortable that was the one that would allow us to get to where we wanted to be, and I think the big key crunch for that was the high-definition multimedia interface (HDMI). From a technical point of view, one of the challenges we had was getting the breakout under the BGA, because blind and buried vias on PCBs are very expensive.
CLEMENS: How many layers is the board?
PETER: Six, which is a pretty bog-standard layer count. The only little trick that we used was to put blind vias only on layers one and two—so we had an extra drilling stage—but only one bonding stage. So that added $0.02 onto the cost of the board. But, because the next layer down was a ground plane, it meant that a lot of the connections that come out of the Broadcom processor just go down one layer. And that meant that I could have space underneath to route other things and actually make it all happen.
CLEMENS: Don’t they have guidelines at Broadcom?
PETER: Oh, they do have guidelines! Use blind and buried vias or vias in pads. Our first prototype was all singing, all dancing, but it would have cost $100 to $110 to manufacture. So we got the machete out and started hacking down all the things that we didn’t need. So you’ve got all the functionality that you want. You can get the performance that you want, you can get the compliance, but it’s got nothing extra.
CLEMENS: Have you been thinking about the future of Raspberry Pi?
PETER: Well, yeah… In our industry, you know, Moore’s law guarantees that everything is old-hat in two years’ time. So we’re thinking about it, but that’s all we’re doing. We’re trying to improve our educational release. I mean, let’s face it, I’m not going to pretend that the Raspberry Pi is perfect. We only made one modification to the board from design to release. We’ve only made some minor modifications under the V2 release. Some of that is to fix some anomalies, some of that was also to help our new manufacturing partner, Sony (in Pencoed, Wales), take it. Their process needed some slight changes to the board to make it easier to manufacture.
CLEMENS: About the original idea of Raspberry Pi, the educational thing. I had a look at the forum and there are lots of forums about technical details, quite a lot of questions and topics about start-up problems. But the educational forum is pretty small.
PETER: You’re right. You’re absolutely right. A lot of that work has been going on slowly and carefully in the background. To be completely honest with you, we were caught on the hub with the interest with Raspberry Pi, and so I’ve certainly spent the last 12 months making sure that we can deliver the product to our community so that they can develop with it and perhaps talk a little bit about our educational goals. But we’re absolutely refocusing on that.
CLEMENS: First, get the hardware into people’s hands and then focus on the education.
PETER: Exactly. And of course, we’ve also released the first computers in schools as manual teaching tools. But also we’ve got Clive, who is a full-time employee helping with the educational deployment. And it’s great that we’ve had all this support (from Google Giving) to get 15,000 kits into schools. I won’t pretend we don’t have a lot of work to do but, I think of where we were a year ago, just still trying to launch.
CLEMENS: It all went really fast.
PETER: Oh yes, it’s gone like a rocket!
CLEMENS: Have you personally learned something valuable from it?
PETER: Well, I’ve learned lots of things. I think the most valuable, maybe not a lesson, but a reinforcement of something I already thought, is that education doesn’t just exist in the classroom. It exists all around us. The opportunity to learn and the opportunity to teach exists every day in almost every aspect in what we do. You know, there are people who spend their lives trying to keep every secret, keep everything to themselves. But there are also people who just give. And I’ve met so many people who are just givers. I suppose I’ve learned there is a whole new system of education that goes on outside of the standard curriculum that helps people do what they want to do.
Editor’s Note: Interview by Clemens Valens, Transcription by Joshua Walbey.
- Embedded Linux Wiki, “RPi Gertboard,” elinux.org/RPi_Gertboard
- Massachusetts Institute of Technology Media Lab, “Scratch,” scratch.mit.edu
- University of Manchester School of Computer Science, Projects Using Raspberry Pi, “Pi-Face Digital Interface,” http://pi.cs.man.ac.uk/interface.htm
Circuit Cellar's editorial team comprises professional engineers, technical editors, and digital media specialists. You can reach the Editorial Department at firstname.lastname@example.org, @circuitcellar, and facebook.com/circuitcellar