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Category Archives: computing

If someone searched my office or my house, or even my car, it would be almost impossible not to disturb the precious layers of dust in what may look like chaotic piles of stuff lying around. The chaos is actually an illusion. If left undisturbed, I tend to know where things are. For many years, I have kept stuff around me when I work (and play). I don’t like the idea of filing cabinets, inboxes, outboxes and there are never enough bookshelves (or enough walls) available to hold all books. Anyhow, there’s all this stuff apparently lying about and it is probably possible to use some forensic archaeology technique to find out how long it’s been since I last accessed various piles of things. But if anybody else moves my stuff, I notice (and may not be able to find things).
Now, in the digital world it’s different. We’re forced by operating systems to have files and folders/directories, everything has a number of date and time stamps, permission settings, etc. Wouldn’t it be nice if we could have some kind of digital dust, slowly settling on our digital file systems so that we easily can detect if someone (3 letters, probably) have snooped around. Perhaps some accumulative encryption. Perhaps it should be probabilistic. For the intruder, the probability of any particular bit being 1 or 0 will be getting fuzzier over time.
All of this is, of course, pure speculative imagination. But the idea is tempting.

digital dust

Web-hosting companies promise a lot, and sometimes charge a lot. You may think that you’re putting your site on a powerful server with excellent bandwidth and performance. It may appear to be so until you get some serious traffic to your site. The Irish ISP and hosting company Digiweb just proved that they cannot deliver what they promise. Just when we needed the to be there, Digiweb failed miserably. For two days in a row, their servers DoS, keel over, etc., when our users, try to access our site. Shame on you Digiweb. It’s time to consider another hosting solution.

For Science Day 2012 at UL, we decided to build a fun controller and sound synthesis demo. Over the past few years, we’ve had a number of postgraduate students exploring for example Galvanic Skin Response for artistic expression. It was slightly surprising to see the hype when Makey Makey launched earlier in 2012. I was puzzled that they didn’t seem to be aware of the work by for example Erkki Kurenniemi and Ralph Lundsten in the late 1960s and early 1970s. Kurenniemi’s DIMI-S is Lundsten’s Love Machine.
We were inspired by the original work by Kurenniemi and Lundsten and we designed and built a 16 channel analogue resistance multiplexer. The circuit uses four inexpensive CMOS chips (CD4051, 8-channel mux) and a couple of transistors (connected as a current mirror), connected to an Arduino and then to a laptop running Pure Data (PD). The Arduino controls what two pins that are active at any given time, rapidly scanning the whole matrix of possibilities (there are 240 possible connections, with 16 channels).
LoveMachine++ interface circuit
We then designed a sound synthesis system in Pure Data (PD) with both a spectral synthesizer, taking the parameters from the resistance matrix and doing a reverse Fast Fourier Transform, and a sequencer, where the mixing and filtering is controlled by the resistance matrix.
LoveMachine++ demo setup
We had to explain to the first few students that they had to touch at least two fruits or vegetables to get sound. After about an hour, word was spreading and experimentation flourished, with several students holding on to vegetables, shaking hands, touching foreheads, etc.

A short video clip from today’s demo.

Schematic diagram

LoveMachine++ interface Schematic Diagram

Bill of Materials

Name Value/Type Description Quantity
D1-3 1N4148 Diode 3
IC1-4 CD4051 8 channel analogue multiplexer 4
Q1-2 BC556 PNP transistor 2
R1 560K Resistor, 0.25W 1
R2 220K Resistor, 0.25W 1
R3 47K Resistor, 0.25W 1

Source code

Arduino code

PD patch

[note: I cobbled together a simple communication protocol in the code and patch above. Basically, an ASCII-based fixed packet length with a terminator character, which makes it easy to see and debug]


Some background on Kurenniemi’s work:

Mikko Ojanen, Jari Suominen, Titti Kallio, Kai Lassfolk (2007) Design Principles and User Interfaces of Erkki Kurenniemi’s Electronic Musical Instruments of the 1960’s and 1970’s, Proceedings of the International Conference on New Interfaces for Musical Expression, pp. 88–93.

It is a real mystery that a lot of people think that touch screen and multi-touch technology is a novelty. Touch screens have a long history, see for example Bill Buxton‘s extensive research on this topic.
In my own work, I stumbled into touch screen research around 1984, while speculating about possibilities to optically interconnect VLSI circuits through optically transmissive substrates. As my own lab did not have the facilities to try out some of the ideas on a micro-scale, we fiddled with normal sized opto-components and circuits, assuming that the principles would scale down if we ever managed to get a budget to pursue this radical idea.
We never found any funding for the VLSI optical interconnects, but we continued to explore the possibilities with the experimental setup, which resulted in the largest touch screens in the world at the time.

Early touch screen prototype, 1986

We were very lucky to get in contact with the local transport company in Gothenburg who gave us an order for three prototype systems. This, in turn, led to contacts with Swedish Rail, via KNM electronics, and a full deployment of our touch technology at all railway stations in Sweden.

One of the first full-scale touch screen for public transport info. 1988

One of the STINS systems, developed for Swedish Rail. 1989.

As my own interest was and remain to make new prototypes, I refocused on making slightly smaller devices that would fit around normal computer screens, CRTs. We succeeded in designing such a smaller system, more lightweight and less expensive.

The VENTRI prototype. A General Purpose Portable Communicator with a touch screen. 1992

This led to explorations of how touch technology may be used by users with different forms of physical disability. We participated in the EU initiative TIDE – Technological Initiative for Disabled and Elderly. In this European collaboration we came to work together with Speech Technology Ltd and Circuits Test and Systems Ltd  at Trinity College in Dublin. The collaboration resulted in a pretty amazing prototype of a General Purpose Portable Communicator targeted at users who could not speak and with various degrees of physical and cognitive impairment. Unfortunately, we couldn’t find funding for any volume production and marketing of the device.

Touch screen for London Underground passenger info. 1993.

Later, I came in contact with Multimedia Technologies Ireland (MTI) in Plassey Technological Park in Limerick and Trinity College in Dublin. Together with MTI, we developed two prototypes of a system for interactive passenger information for London Underground.

My smallest touch screen prototype. Handheld. 1994.

I also started to fiddle with a really small device, a handheld unit. I made one single prototype and tried to show it, in confidence, to a few of the larger manufacturers. The one and only prototype disappeared during one of these excursions and I only have one single photo left of it, from around 1994.

Looks familiar, doesn’t it?

A first sketch of a new custom controller.

  • Sliders fading up and down
  • Knobs for turning
  • Cranks for turning
  • Buttons for activation – perhaps with aftertouch (force sensitive)
  • Switches for turning things on or off.
  • Wheels for turning
  • Squishy things for squeezing

USB i/o, perhaps using OSC protocol.

Build in a flight case.

controller sketch

This afternoon, I finally handed over the Course Directorship for UL‘s Masters in Interactive Media to my colleague Cristiano Storni. It’s been 12 long and exciting years with between 10 and 17 graduates per year. We now have graduates in many different countries around the world, at work ranging from teaching to new start-up companies to the usual multinationals.

It’s also about 14 years ago we started to discuss the need for a postgraduate course like this. It’s amazing how quickly time is passing, as well as how technology has evolved.

Over the past few days I have noticed that even without having a browser window or tab with Facebook open, suddenly you get a pop-up warning that the browser cannot authenticate over a https connection. I find this quite alarming as this implies that either, some spyware that I haven’t identified and zapped yet has come onboard the computers in question, or, that Facebook are leaving some extraordinary crap behind until you close and restart your browser, or, that other web sites are trying to exploit security holes in Facebook.

Computers used: MacBook Pro/OSX 10.5.8 and iPad (version1) iOS 4.3.3
Browsers: Safari and Firefox.

Is anybody else noticing this?

(Why OSX 10.5: it’s what I have on one of my machines. I haven’t tested this on 10.6 etc yet)