快猫短视频

A gliding sensor inspired by Javan cucumber seeds could be used for environmental monitoring, and then quickly biodegrade, leaving no waste behind.

Ecologists routinely use sensors to collect data on temperature, humidity, pH and other variables to better understand ecosystems. But when these sensors are left behind, the electronic waste ends up polluting the environment.

Now, Fabian Wiesem眉ller at the and his colleagues have taken a biodegradable sensor and fitted it to a glider they have made that will also break down in soil.

鈥淲e were motivated to introduce new technologies that could help in the long term to make more sustainable devices and electronics,鈥� says Wiesem眉ller.

The design of the device is based on the winged seeds of the Javan cucumber, which glide for long distances when they fall from high in the forest canopy and have inspired the wing structure of many gliders.

The team made the glider out of starch paper, placing an actuator that houses a pH sensor at the centre. The actuator is made from a mixture of cellulose fibres and gelatin, and it is covered with a resin called shellac. The sensor is essentially a coating of litmus, which changes colour to show the acidity of the soil where it lands.

The actuator acts as a protective cover, and the material expands and opens to expose the sensor only at a certain level of humidity, which normally occurs when it rains.

Once a group of the gliders are released from a drone, they will either glide or spiral down, depending on the wind conditions and how warped they are due to humidity.

This would spread the gliders over a wide area, says the team. In the experiments, the glider travelled for about 50 metres when released from a height of 10 metres.

The drone can then visually scan the colour change of the fallen sensors to build a map of the pH levels across the area.

The team tested the biodegradability of the gliders by burying them in soil in the lab. After seven days, the wings had completely degraded. It would take about 100 days for the rest of the components to disintegrate, says Wiesem眉ller.

The work is promising, says at the Ashoka Trust for Research in Ecology and the Environment, India. 鈥淗owever, there would be on-field challenges. Forest environments are often unpredictable, and the sensor might face challenges in how it perceives and navigates the forest and responds to unpredictable forces like winds,鈥� he says.

鈥淪uch sensors could also be used to observe the effects of pollution caused by industrial complexes on the microclimate at the local level,鈥� says Wiesem眉ller. The team would like to move towards capturing audio and images, he says.