Tag Archives: locative audio

Sonic Bikes to Sonic Kayaks – using puredata

When I first started working on the Sonic Bikes project with Kaffe Matthews in 2013 I had just moved to Cornwall, and I used the Penryn river for developing “The swamp that was” installation we made for Ghent. We’ve always talked about bringing this project here, but the various limitations of cycling (fast roads, stupid drivers and ridiculous hills) were always too much of a problem – so we wondered about sonic kayaks, as a distant vague idea. However now, thanks to help from the British Science Association, Feast Cornwall and the Port Eliot Festival they are fast becoming a reality!

We’re also using this opportunity to convert kayaks into instruments for sensing marine microclimates – an area which is currently lacking in scientific knowledge. In order to do this, we need to expand the sonic potential of our current system – moving it from sample playback to a more open ended synthesis approach. We’re running a open hacklab to trial the use of sensors, and actually get out on the water with Kaffe later in the month.

zones

To do all this – and keep it functioning on a Raspberry Pi, we’re using Pure Data. For the moment it seemed most appropriate to stick to the concept of audio zones, previously these defined areas associated with samples that would play back when you were inside of them. The screenshot above is the sonic bike mapping tool – recently rebuilt by Francesca. Using Pure Data we can associated each zone with a specific patch, which leaves the use of samples or not, effects, interpretation of sensor data and any other musical decisions completely open.

pd

The patch above is the first version of the zone patch mixer – it reads OSC messages from the GPS map system (which is written in Lua) and when a patch is triggered, it turns on audio processing for it and gradually fades it up. When the zone is left it fades it down and deactivates it – this way we can have multiple overlayed patches, much like the sample mixing we used before. We can also have loads of different patches as it’s only processing the active ones at any one time, it won’t stress out the Raspberry Pi too much.

I’ve been testing this today by walking around a lot with headphones on – this is a GPS trace, which gives some ideas of the usual problems of GPS (I didn’t actually switch to kayak halfway through, although it thought I did).

trace

Sonic Bike Hacklab Part 3: The anti-cloud – towards bike to bike mesh networking

IMG_20130726_122857

[Continued from part 2] One of the philosophies that pre-dates my involvement with the sonic bikes project is a refusal of cloud technologies – to avoid the use of a central server and to provide everything required (map, sounds and computation) on board the bikes. As the problems with cloud technology become more well known, art projects like this are a good way to creatively prototype alternatives.

The need to abstractly “get the bikes to talk to one another” beyond our earlier FM transmission experiments implies some kind of networking, and mesh networking provides non-hierarchical peer to peer communication, appropriate if you want to form networks between bikes on the street over wifi (which may cluster at times, and break up or reform as people go in different directions). After discussing this a bit with hacklab participant and fellow Beagleboard enthusiast Adam Parkinson I thought this would be a good thing to spend some time researching.

The most basic networking information we can detect with wifi is the presence of a particular bike, and we decided to prototype this first. I’d previously got hold of a low power wifi usb module compatible with a Raspberry Pi (which I found I could run with power from the bike’s beagleboard usb!), and we could use an Android phone on another bike, running fluxa to plug the signal strength into a synth parameter:

mesh

It’s fairly simple to make an ad-hoc network on the Raspberry Pi via command line:

ifconfig wlan0 down
iwconfig wlan0 channel 4
iwconfig wlan0 mode ad-hoc
iwconfig wlan0 essid 'bikemesh'
iwconfig wlan0 key password
ifconfig wlan0 192.168.2.1

On the Android side, the proximity synth software continuously measures the strength of the wifi network from the other bike, using a WifiScanReceiver we set up like so:

wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
wifi.startScan();
registerReceiver(new WiFiScanReceiver(), 
                 new IntentFilter(
                 WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));

The WifiScanReceiver is a subclass of BroadcastReceiver, that re-triggers the scan process. This results in reasonably high frequency scanning, a couple a second or so and we also check the SSID names of the networks around the bike for the correct “bikemesh” node:

import java.util.List;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.util.Log;
import android.widget.Toast;

public class WiFiScanReceiver extends BroadcastReceiver {
    private static final String TAG = "WiFiScanReceiver";

    public WiFiScanReceiver() {
        super();
        Level=0;
    }

    static public int Level;

    @Override
    public void onReceive(Context c, Intent intent) {
        List<ScanResult> results = ((Earlobes)c).wifi.getScanResults();
        ScanResult bestSignal = null;

        for (ScanResult result : results) {
            if (result.SSID.equals("bikemesh")) {
                String message = String.format("bikemesh located: strength %d",
                                               result.level);
                Level = result.level;
            }
        }
        ((Earlobes)c).wifi.startScan();
    }

}

The synth was also using the accelerometers, but ramped up the cutoff frequency of a low pass filter on some white noise and increased modulation on the accelerometer driven sine waves when you were close to the other bike. The result was quite surprising with such a simple setup, as it immediately turned into a game playing situation, bike “hide and seek” – as rider of the proximity synth bike you wanted to hunt out where the wifi bike was, the rider of which would be trying to escape. The range was surprisingly long distance, about halfway across London Fields park. Here is an initial test of the setup (we had the sounds a bit more obvious than this in later tests):

With the hardware and some simple software tested, the next stage would be to run multiple wifi nodes and get them to connect and form a mesh network. I got some way into using Babel for this, which is very self contained and compiles and runs on Beagleboard and Raspberry Pi. The other side to this is what kind of things do we want to do with this kind of “on the road” system, how do we notate and artistically control what happens over a sonic bike mesh network?

Some ideas we had included recording sounds and passing them between bikes, or each bike forming a synth node, so you create and change audio dependant on who is around you and what the configuration is. I made few more notes on the technical stuff here.

Sonic Bike Hacklab: Part 1

IMG_20130726_122148

Time to report on the sonic bike hacklab Kaffe Matthews and I put on in AudRey HQ in Hackney. We had a sunny and stormy week of investigation into sonic bike technology. After producing three installations with sonic bikes, the purpose of the lab was to open the project up to more people with fresh ideas, as well as a chance to engage with the bikes in a more playful research oriented manner without the pressure of an upcoming production.

IMG_20130726_121414

Each of the three previous installation, in Ghent, Hailuoto island, Finland, and Porto, we’ve used the same technology, a Beagleboard using a GPS module to trigger samples to play back over speakers mounted on the handlebars. The musical score is a map created using Ushahidi consisting of zones tagged with sample names and playback parameters that the bikes carry around with them.

swamp

We decided to concentrate on two areas of investigation, using the bike as a musical instrument and finding ways to get the bikes to talk to each other (rather than being identical independent clones). We had a bunch of different components to play with, donated by the participants, Kaffe and I – while the bikes already provided power via 12v batteries, amplification and speakers. We focused on tech we could rapid prototype with minimal fuss.

components

The next few posts will describe the different experiments we carried out using these components.

‘The Marja trio’ – Sonic Bike Experience for Marjaniemi

I’ve been doing more remote install work on Kaffe’s latest piece she’s been building while resident at Hai Art in Hailuoto, an island in the north of Finland. The zone building, site specific sample composing and microscopic Beagleboard log debugging is over, and two new GPS Opera bikes are born! Go to Hai Art or Kaffe’s site for more details.

The Marja trio_score2_KM2013

183123_486670614739967_1256052974_n

Screen Shot 2013-05-03 at 9.55.33 AM

Bike Opera – layering sounds in space

New advancements on the the bike opera project with Kaffe Matthews include a brand new mapping tool based on, yes you guessed it – Ushahidi which I’ve been using for a lot of wildly different projects recently. This time the work has been mainly focused in improving the area mapping – adding features for editing polygons so Kaffe can layer her sounds in space:

swamp-edit

This work is fairly reusable, as it only concerns changes to the submit_edit_js.php file in the standard Ushahidi install. In the meantime, Kaffe has been collecting sounds from musicians in Porto and building up a work of truly operatic proportions. We keep our fingers crossed that the bike mounted BeagleBoards can cope with all this material!

Angelika

Swamp bike opera impressions…


Photo thanks to zzkt

As the coder for “The swamp that was…” bike opera, my view of things was from “inside” the bikes – listening to the GPS data and playing samples. So it was super (and somewhat surreal) to finally become a rider and take one of the bikes (called Nancy) for a spin through the streets of Ghent to experience it like everyone else at the Electrified festival.

I followed the different routes, and tried some out backwards and got lost in the “garden” – the zone of mysterious ghost butterflies and wandering sounds. During the end of the final route shelter had to be sought in Julius de Vigneplein during a gigantic thunderstorm, to the sound of looping saxophones before retreating back to the Vooruit.

It didn’t crash (always my main preoccupation with testing something I’ve been involved with writing software for) and there seemed to be continuous audio from the routes. Once I had ascertained that the software seemed to be working properly I could actually start to pay attention to the sounds which were a very fluid mix, interspersed with sudden bursts of Flemish – recordings of local people.

The sounds are a widely varied mix ranging from digital glitch to ethereal sounds and processed ducks that accompany you as you cycle along the canals. The “garden” is not a route as such but occupies a maze of small streets in the Ledeberg area and populates the streets with many insects, birds and other surprises.

The custom bike/speaker arrangement designed and built by Timelab was satisfyingly loud – pulling up next to other innocent cyclists at junctions with blaring jazz is quite an intriguing social experience. It makes you want to say “I can’t turn it off” or “I am an art installation!” The beagleboards also seem fairly durable, as the bikes have been running for a month now, and the cobbled streets and some areas with bumpy roadworks give them a lot of shocks to cope with.

The “click click” of car indicator relays tell you when you’ve reached junctions where you have to turn, and while our method of calculating direction (by comparing positions every 10 seconds) doesn’t really work well enough, they still had a useful role, saying “pay attention, you need to turn here!”. This installation, and the rest of the festival will be running for another month, until the 4th November.

‘The swamp that was’ – a bicycle opera from the ground of Ganda (part 5)

The Bicycle Opera is now live, get your bikes from the Snoepwinkel, Sint-Pietersnieuwstraat 21:

A bicycle opera in Ghent! British sound artist Kaffe Matthews records urban sounds such as music, singing and street sounds. As she combines these with elements from the past, she creates an unseen urban opera. A mobile composition, written for cyclists. You can rent an “audio bike” to explore the streets of Ghent. As you ride past certain spots, sound recordings are played on the speakers of your bike, uncovering the soundtrack of the city piece by piece.

Here is a visualisation of the zones (including the moving ghost zones) across the city.