Researchers at the University of Washington (UW) have taken a step toward bug-powered surveillance by creating small, lightweight cameras and strapping them to the backs of a death-feigning beetle and a Pincacate beetle.
As anyone who owns a smartphone knows, cameras have been getting smaller and better for decades. While the optics and related wiring can be made extremely lightweight, the batteries tend to be too heavy for use in super-small drones or, for instance, strapping to the back of an insect.
The UW researchers overcame this weight challenge by creating a system that clocks in at just about 250 milligrams, which is approximately one-tenth of the weight of a playing card. To keep the power demands of the system as low as possible, the researchers turned to nature itself.
“Similar to cameras, vision in animals requires a lot of power,” said Sawyer Fuller, a UW assistant professor of mechanical engineering and the co-author of a study that will appear in Science Robotics on July 15. “It’s less of a big deal in larger creatures like humans, but flies are using 10 to 20 percent of their resting energy just to power their brains, most of which is devoted to visual processing. To help cut the cost, some flies have a small, high-resolution region of their compound eyes. They turn their heads to steer where they want to see with extra clarity, such as for chasing prey or a mate. This saves power over having high resolution over their entire visual field.”
So the researchers designed their camera in a similar way. Rather than taking in visual data from a large field, the camera concentrates its focus straight ahead. To move the camera up to 60 degrees in any one direction, the researchers can send an electrical pulse to the system using the Bluetooth signal from a smartphone that causes an arm to bend. After about a minute, the arm relaxes and naturally returns to its original position, again saving energy.
“One advantage to being able to move the camera is that you can get a wide-angle view of what’s happening without consuming a huge amount of power,” said co-lead author Vikram Iyer, a UW doctoral student in electrical and computer engineering. “We can track a moving object without having to spend the energy to move a whole robot. These images are also at a higher resolution than if we used a wide-angle lens, which would create an image with the same number of pixels divided up over a much larger area.”
Another way in which the system conserves power is through the use of an onboard accelerometer that only turns the camera on when the beetle is moving. The camera relays a video feed to the smartphone shot at about 1-5 frames per second, so we’re not talking Spielberg-level quality, but the view from the beetle’s back is certainly impressive considering the size of the system. The camera can transmit its signal from about 120 meters away, and its power lasted more than six hours if the beetle wasn’t very active.
But Why Take the Trouble in the First Place?
“This is the first time that we’ve had a first-person view from the back of a beetle while it’s walking around,” Iyer said. “There are so many questions you could explore, such as how does the beetle respond to different stimuli that it sees in the environment? But also, insects can traverse rocky environments, which is challenging for robots to do at this scale. So this system can also help us out by letting us see or collect samples from hard-to-navigate spaces.”
On top of that, the researchers found that when they strapped the same camera equipment to tiny robots, vibrations from the motor caused the video to become unusable. The beetle cams didn’t suffer from the same issue.
What Do the Beetles Have to Say About All This?
Well, nothing of course. However, the researchers do point out that the equipment they strapped to the back of the bugs didn’t hamper their movements in any way and that they were able to climb trees and walk across gravel and up slopes. Also, the beetles survived for at least a year after their careers in cinema ended.