sonification – dave's blog of art and programming

Sonic Kayaks: musical instruments for marine exploration

Here is a bit of a writeup of the gubbins going into the sonic kayaks project. We only have a few weeks to go until the kayaks’ maiden voyages at the British Science Festival, so we are ramping things up, with a week of intense testing and production last week with Kirsty Kemp, Kaffe Matthews and Chris Yesson joining us at FoAM Kernow. You can read Amber’s report on the week here.

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setup-annotated

The heart of the system is the Raspberry Pi 2. This is connected to a USB GPS dongle, and running the sonic bike software we have used in many cities over the last couple of years. We have some crucial additions such as two water temperature sensors and a hydrophone. We have also switched all audio processing over to pure data, so we can do a lot more sound wise – such as sonify sensor data directly.

How to do this well has been a tricky part to get right. There is a trade off between constant irritating sound (in a wild environment this is more of a problem than a city, as we found out in the first workshop) and ‘overcooking’ the sound so it’s too complex to be able to tell what the sensors are actually reporting.

watertempsine

This is the current pd patch – I settled on cutting out the sound when there is no change in temperature, so you only hear anything when you are paddling through a temperature gradient. The pitch represents the current temperature, but it’s normalised to the running minimum and maximum the kayak has observed. This makes it much more sensitive, but it takes a few minutes to self calibrate at the start. Currently it ranges from 70 to 970 Hz, with a little frequency modulation at 90 Hz to make the lower end more audible.

Here it is on the water with our brand new multi-kayak compatible mounting system and 3D printed horn built in blender. The horrible sound right at the start is my rubbish phone.

In addition to this, we have the hydrophone, which is really the star of the show. Even with a preamp we’re having to boost it in pure data by 12 times to hear things, but what we do hear is both mysterious and revealing. It seems that boat sounds are really loud – you can hear engines for quite a long way, useful in expanding your kayak senses if they are behind you. We also heard snapping sounds from underwater creatures and further up the Penryn river you can hear chains clinking and there seems to be a general background sound that changes as you move around.

We still want to add a layer of additional sounds to this experience for the Swansea festival for people to search for out on the water. We are planning different areas so you can choose to paddle into or away from “sonic areas” comprising multiple GPS zones. We spent the last day with Kaffe testing some quick ideas out:

Looking at sea temperature and sensing the hidden underwater world, climate change is the big subject we keep coming back to, so we are looking for ways to approach this topic with our strange new instrument.

Red King progress, and a sonification voting system

We have now launched the Red King simulation website. The fundamental idea of the project is to use music and online participation to help understand a complex natural process. Dealing with a mathematical model is more challenging than a lot of our citizen science work, where the connection to organisms and their environments is more clear. The basic problem here is how to explore a vast parameter space in order to find patterns in co-evolution.

After some initial experiments we developed a simple prototype native application (OSX/Ubuntu builds) in order to check we understand the model properly by running and tweaking it.

The next step was to convert this into a library we could bind to python. With this done we can run the model on a server, and have it autonomously update it’s own website via django. This way we can continuously run the simulation, storing randomly chosen parameters to build a database and display the results. I also set up a simple filter to run the simulation for 100 timesteps and discard parameters that didn’t look so interesting (the ones that went extinct or didn’t result in multiple host or virus strains).

There is also now a twitter bot that posts new simulation/sonifications as they appear. One nice thing I’ve found with this is that I can use the bot timeline to make notes on changes by tweeting them. It also allows interested people an easy way to approach the project, and people are already starting discussions with the researchers on twitter.

Up to now, this has simply been a presentation of a simulation – how can we involve people so they can help? This is a small project so we have to be realistic what is possible, but eventually we need a simple way to test how the perception of a sonification compares with a visual display. Amber’s been doing research into the sonification side of the project here. More on that soon.

For now I’ve added a voting system, where anyone can up or down-vote the simulation music. This is used as a way to tag patterns for further exploration. Parameter sets are ranked using the votes – so the higher the votes are the higher the likelihood of being picked as the basis for new simulations. When we pick one, we randomise one of its parameters to generate new audio. Simulations store their parents, so you can explore the hierarchy and see what changes cause different patterns. An obvious addition to this is to hook up the twitter retweets and favorites for the same purpose.

Sonic Kayaks Hacklab

Part one of our two events for British Science Week was the Sonic Kayak open Hacklab with Kaffe Matthews and Dr. Kirsty Kemp. Amber has reported our findings here, this was the first time we successfully trialled the technology and ideas behind the Sonic Kayak, in future we will be refining them into instruments for experiencing the marine world. More on that soon!

Red King: Host/Parasite co-evolution citizen science

A new project begins, on the subject of ecology and evolution of infectious disease. This one is a little different from a lot of Foam Kernow’s citizen science projects in that the subject is theoretical research – and involves mathematical simulations of populations of co-evolving organisms, rather than the direct study of real ones in field sites etc.

The simulation, or model, we are working with is concerned with the co-evolution of parasites and their hosts. Just as in more commonly known simulations of predators and prey, there are complex relationships between hosts and parasites – for example if parasites become too successful and aggressive the hosts start to die out, in turn reducing the parasite populations. Hosts can evolve to resist infection, but this has an overhead that starts to become a disadvantage when most of a population is free of parasites again.

Example evolution processes with different host/parasite trade-offs.

Over time these relationships shift and change, and this happens in different patterns depending on the starting conditions. Little is known about the categorisation of these patterns, or even the range of relationships possible. The models used to simulate them are still a research topic in their own right, so in this project we are hoping to explore different ways people can both control a simulation (perhaps with an element of visual live programming), and also experience the results in a number of ways – via a sonifications, or game world. The eventual, ambitious aim – is to provide a way for people to feedback their discoveries into the research.