Located in Botswana, the Okavango Delta is one of the last pristine wetland wildernesses in the world. Although it is protected as an UNESCO World Heritage Site, the water supply further upstream in Angola and Namibia is still susceptible to human interference. And so, National Geographic’s Okavango Expedition assembled a team of scientists and engineers to gather data along the river so that conservation efforts can be more effective, raise awareness and ensure that this remote wildlife sanctuary can be enjoyed for generations to come.
Since the delta itself stretches a vast 5,800-square-miles, the researchers needed to find a way to efficiently gather data across the entire area. Being such a remote location presented a few challenges, which required additional considerations like weatherproof equipment, power sources, and more importantly, how to network the sensors.
In order to accomplish this, the expedition’s lead technologist Shah Selbe created a wireless sensor network to significantly reduce the amount of manual labor required by the team to accumulate the environmental data. Now, they no longer have to use pH strips or manually check sensor readings, then record it by hand onto paper. Instead, the wireless network automates this processing by accurately collating the information.
“Shah took us from little strips and pieces of paper – writing down the water quality as we go down – to environmental sensor platforms. We’re going to be measuring the literal heartbeat of that wilderness in real-time for the world to see,” says Steve Boyes, National Geographic Emerging Explorer.
At the heart of each network lies a Raspberry Pi running a Python script. This central hub processes the data generated from multiple remote nodes and acts as a Wi-Fi gateway. The data is then directly uploaded to the web server using JSON. In some particularly remote areas, Arduino nodes are employed to relay data using the Twilio API over a cellular network. These nodes are comprised of an Arduino, multiple sensors and an XBee module, which makes it possible to connect over long distances. For power, the remote nodes rely on a solar panel and a 6600 mAH battery.
An assortment of sensors are being deployed throughout the delta, with hopes of garnering various water quality data like pH, dissolved oxygen, salinity and conductivity. The team is also seeking to better understand flood dynamics by monitoring flow rate, water level and turbidity. On the surface, sensors measure air temperature, humidity, barometric pressure and in the future the researchers plan to add sensors to detect radiation and other air pollutants. Aside from all that, they are even streaming GPS location, research observations, wildlife sightings, photos and more in real-time on their website.
As the XBee crew reveals, this is merely the first phase of the project. Continuously monitoring the delta will enable the National Geographic explorers to detect even the most minute changes in water quality. The project will also be open source, so the conservation effort can reach and preserve as many marine habitats as possible.
“Instead of connected toasters and thermostats, we can have connected forests and wetlands,” Selbe explains.
Intrigued? You can read more about the project on Digi’s original post here, or check out Selbe’s own writeup.