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Category Archives: electronics

LoveMachine++

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]

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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.

Challenging times for learning science and technology

When I was growing up, I really enjoyed learning by experimenting with all kinds of things. I also learnt a lot from various educational science kits that sympathetic parents bought, probably trying to facilitate my interests (or hoping to contain the interests on the safe side of science and technology). There were all kinds of exciting kits, ranging from The Little Electrician, to the Chemistry kit, to the Nuclear Energy exploration kit….

In addition to this, it was really fun to combine the kits with Lego, Meccano and bits and pieces from broken things found in the basement.
Back in the 1960s, it was also possible, as a kid, to walk in to the local pharmacy and buy all kinds of interesting stuff (e.g. HCL, HNO3, H2SO4, NH3, more or less the whole chemical alphabet….). You could also get a good variety of electronic components in all radio shops.

Later in life, I have always tried to choose stuff with open-ended educational value when buying (or making!) birthday gifts to young people. Sadly, the possibility to send anything interesting abroad by post has recently been made almost impossible.

The Irish postal service An Post now demand that you fill out an Aviation Security Declaration when sending a larger letter or small parcel. As far as I have googled this, it’s a fairly recent thing (February 2012?). Perhaps it’s the UK that have forced Ireland into this, as most of the stuff posted in Ireland with destinations in Europe pass through the UK, and with the Olympics and other silly antics around the corner, they are really paranoid about everything.

This leaves me with the only option, to post the most dangerous of all things: books. Books may contain ideas that may change the world.

A Touching Story

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?

Whatyoumaycallitron v0.1

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

Virtual trad and hyper-trad instruments

During the Sounding Object project, we researched and developed new approaches for sound on computers, responsive to physical interaction and easily matched to physical objects. One of the demos was the Vodhran, a virtual Irish Bodhran drum. The performers gestures are tracked using a Polhemus Fastrak 6-DOF electromagnetic tracker in realtime and the sound synthesized in real-time by our sound object models.


This summer, I’m planning to make another version of this, probably the Hodhran – a Hyper-bodhran, using a real bodhran, parts of a Wii controller, an Arduino and a few sensors (such as force sensitive resistors and bend sensors).

Me and synths

In the mid-1960’s, I first heard the sound of a synthesizer. When Wendy Carlos‘ album Switched on Bach was released in 1968 I was totally convinced that electronic instruments was the future. As I couldn’t afford to buy a real Moog, I spent a few years studying electronic engineering and telecoms to enable me to build my own, that I eventually used in my final year project in 1975. I think I’ve only one or two of the home-etched circuit boards left in some drawer. I had to disassemble the synth when I finished the final year project, as some parts were borrowed from physics labs, other parts designed and built by me (only recordings remain).

I was delighted today to find the Moog Foundation on the web. I fully agree with their vision that music, and in particular by using electronic instruments like the Moog-range, is an excellent way to get young people interested in art, science and technology. It is a very intuitive way to learn as you can start by exploring a few simple buttons and tweaking a few knobs – and immediately hear the result. The magic of this directness can then easily lead to a feeling of wonder about how it works. When you get onto that path of discovery, you can learn a lot about music, physics, electronics, maths, and a number of other things such as the importance of designing things so that they are suitable for human use. This is probably one of the most important aspects of Bob Moog‘s work. He worked together with musicians. While it is simple to get a knob to change the resonance frequency of a filter, the control curve (the mapping) has to feel natural to the musician (while it may sometimes be a difficult engineering problem to get the right non-linearity, especially when working with analog electronics).
So, here’s to Bob Moog, Wendy Carlos, and many others whose work and art I’ve enjoyed so much over the years, and still do. Let’s keep on designing, building, exploring and making.