Topher White was struck by the sounds of the rainforest while visiting a gibbon reserve in Indonesia during the summer of 2011.
But what the American engineer couldn't hear was the roar of chainsaws and noise of the illegal loggers he knew were relentlessly tearing down trees and endangering the gibbons' natural habitat.
Through his non-profit Rainforest Connection, White repackages old Android smartphones into a recycled plastic box fitted with an extra microphone, battery pack and solar panels. The finished devices look like mechanical flowers and are fastened to trees high up in the canopy, often up to 150 feet.
In a report for CNN’s Call to Earth, White explains how this technology has been developed by Rainforest Connection and how it can be utilised in forests around the globe.
Detecting illegal logging has typically relied on aerial surveys or satellites, which can take days or weeks to alert rangers to tree cover loss, but Rainforest Connection says its phones are a faster and cheaper alternative.
White explained: "They capture all the sounds from the rainforest and stream it up to the cloud where our software runs on it with a few different types of AI to pick out all sorts of things, so chainsaws, logging trucks, people, gun shots. And then we can send real time alerts over the cell phone network to locals on the ground."
Once the rangers receive an alert to their own phones, they can determine whether the activity is suspicious based on its location, White says.
Forests are home to 80 percent of the world's land-based species, more than one billion people depend on them for their livelihoods and they can help mitigate climate change by absorbing carbon dioxide. But WWF estimates that we are losing 18.7 million acres of forests a year, equivalent to 27 soccer fields every minute.
The UN also estimates that deforestation and forest degradation accounts for around 11 percent of global carbon emissions.
Rainforest Connection now has more than 150 active devices used by local partners to protect areas of rainforest in five countries, including Peru, Cameroon and Brazil.
White said: "Every square kilometre that you can avoid being deforested is equivalent to taking 1,000 cars off the road for a year. Considering the millions of square kilometres that are out there, it's probably the cheapest way to stall climate change."
However, illegal timber continues to be lucrative. A report from the UN and Interpol estimates the global trade is worth between $30 billion and $100 billion every year. Deforestation often starts with selling timber, but also includes clearing the forest for farming and houses.
White explained: "It's so profitable that they will cut roads through the forest to extract high-priced wood and those roads become the gateway to so much more deforestation. If you can stop the roads, you can stop full-scale deforestation."
Alongside preventing illegal logging, the NGO is branching out into what is known as "bioacoustics" - creating a digital library of raw, acoustic data, which it hopes will be used for conservation.
White said: "To date we have gathered well over 100 years of continuous audio, for all these amazing places where it is very wild, where no one goes. The same way we use AI and machine learning to pick out chainsaws, we are building ways by which we can look for different animals and species.
"We've never been able to study this en masse. Bioacoustics is really a revolution as meaningful as the invention of the microscope, when it comes to understanding ecology and nature."
Brendan Montague is editor of The Ecologist. Call to Earth is CNN's commitment to reporting on environmental challenges facing our planet, together with the solutions.