Drone deploys sensors by shooting them as darts
When conducting environmental studies in hard-to-access locations, scientists will often set up wireless networks of small data-logging sensors. Deploying those sensors can be difficult and even dangerous work, though, which is why a dart-shooting drone is being developed to do the job.
Although drones have already been experimentally used for the placement of environmental sensors, the deployment methods have involved either dropping the sensors onto the ground, or sticking them onto vertical surfaces using an attached appendage such as a mechanical arm.
When dropping them, however, it's hard to control exactly where they'll land. Additionally, scientists may not want them to be located on the ground, where they could get trampled or covered in debris. And when pressing them into place using an arm, the drone has to get quite close to the vertical surface – this presents a risk of the aircraft either colliding with the surface itself, or getting caught in obstacles protruding from it, such as tree branches.
With these limitations in mind, a team at Imperial College London created the dart-shooting quadcopter.
It's equipped with a laser-based aiming system, along with a spring-loaded launch mechanism. A trigger made of a shape-memory alloy releases the spring on command, sending the loaded sensor-equipped dart flying vertically through the air to its target. The whole dart-shooting setup weighs 650 grams (1.4 lb) – not counting the drone itself – with each dart tipping the scales at 30 grams.
According to the researchers, the system has a target-hitting accuracy of about 10 cm (3.9 in) when shooting from its maximum range of 4 meters (13 ft). Although that accuracy increases as the shooting distance is reduced, the darts have a correspondingly higher tendency to bounce off of tree trunks instead of sticking into them. For other types of targets, such as the steel legs of oil rigs, magnet- or adhesive-tipped darts could conceivably be utilized instead.
The system can be seen in use, in the video below. In its present prototype form, it can execute up to 17 launches on one battery-charge – that said, the darts currently have to be loaded one at a time. The research is described in a paper that was recently published in the journal IEEE Robotics and Automation Letters.
And for another example of a dart-shooting drone, check out the aptly named DartDrone. Instead of environmental sensors, however, it shoots tranquilizer darts at livestock or wild animals.