Part environmental sensing system, part musical instrument, the Sonic Kayak (magpi.cc/sonickayak) has been developed and fine-tuned over the past four years by the FoAM Kernow studio, run by Dave Griffiths and Dr Amber Griffiths.

After helping out on Sonic Bikes, a sound art project started by Kaffe Matthews, they thought about bringing the bikes to Cornwall, “but it’s a dangerous place for cycling with very few cycle paths and narrow roads,” Amber tells us, “so we started talking about making a version for boats.”

With a background in wildlife conservation genetics, she thought it would be good to add some environmental sensors and try using it to gather underwater data. “So it’s gone from being a pure sound-art project on bikes, to something that has both sound-art and scientific purpose on kayaks. Kaffe’s now working on putting some of the environmental sensors onto the Sonic Bikes, so it’s going full circle.”

Out on the water around Falmouth harbour, gathering environmental data from industrial areas, places where people live on houseboats, where there might be farm run-off etc

Environmental sensors

Each Sonic Kayak kit is equipped with four environmental sensors. Water temperature is measured using a digital thermometer, water cloudiness using a home-made sensor consisting of an LED and an LDR in a dark tube (the amount of light that hits the LDR is a measure of how cloudy the water is), underwater sound using a hydrophone, and above-water air pollution using a laser dust sensor.  There’s also a GPS unit to record the kayak’s geographical co-ordinates, which enables mapping of the environmental data gathered.

Sounds based on the data are played in real-time through waterproof Bluetooth speaker to the kayaker. “This does two things,” explains Amber. “Firstly, it gives people a real connection to the underwater world that is otherwise very hard to understand. Secondly, if you are interested in gathering a particular type of data, for example pollution coming from a large boat, if you can hear when you are entering a polluted area then it allows you to follow that data and collect exactly what you need.”

The system has also proven useful for people with visual impairments. “We’ve been working with an accessible kayak club to develop the system for navigation purposes, to allow people to kayak independently even if they have little or no sight.”

Electronics and water

The kit’s electronics – including a Raspberry Pi 3B and Arduino Nano – are housed in a Bopla Bocube plastic enclosure that fits into the rear of the kayak. The combination of electronics with salt water has proved problematic previously. “One of our earliest Sonic Kayak events was the British Science Festival in 2016, and on the second day the sea was very choppy and both kayaks capsized with the systems on them,” recalls Amber. “We watched all the electronics break apart and wash up on the beach, then almost instantly corrode due to the salt water, which was rather painful! Since then we’ve got very good with embedding electronics in resin, and using rubber seals for the sensor cables.”

While the data gathered so far by the project is proof-of-principle, it may well be of interest to professional researchers. “This type of data is really hard to get, particularly for places close to cliffs or in tidal estuaries, where it’s difficult to take large research boats,” says Amber. “Our system also means you can get very fine-scale data, as opposed to the broader scale sea temperature data you get from satellites, or the data you can get from attaching sensors to buoys.”

However, Amber says they're more interested in getting it into the hands of people who want to use it to map their local environments. “We’ve started working on ways to visualise the data from the Sonic Kayaks on maps, and would love to make a portal where people can upload the data from their kayaking trips, and have it visualised automatically.”

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