Thursday, January 29, 2009

The Army's Remote-Controlled Beetle

The insect's flight path can be wirelessly controlled via a neural implant.

By Emily Singer

Cyborg beetle: Shown here is a giant flower beetle carrying a microprocessor, radio receiver, and microbattery and implanted with several electrodes. To control the insect’s flight, scientists wirelessly deliver signals to the payload, which sends electrical signals through the electrode to the brain and flight muscles. Credit: Michel Maharbiz

Multimedia   Watch controlled flights of the beetle.

A giant flower beetle with implanted electrodes and a radio receiver on its back can be wirelessly controlled, according to research presented this week. Scientists at the University of California developed a tiny rig that receives control signals from a nearby computer. Electrical signals delivered via the electrodes command the insect to take off, turn left or right, or hover in midflight. The research, funded by the Defense Advanced Research Projects Agency (DARPA), could one day be used for surveillance purposes or for search-and-rescue missions.

Beetles and other flying insects are masters of flight control, integrating sensory feedback from the visual system and other senses to navigate and maintain stable flight, all the while using little energy. Rather than trying to re-create these systems from scratch, Michel Maharbiz and his colleagues aim to take advantage of the beetle's natural abilities by melding insect and machine. His group has previously created cyborg beetles, including ones that have been implanted with electronic components as pupae. But the current research, presented at the IEEE MEMS in Italy, is the first demonstration of a wireless beetle system.

The beetle's payload consists of an off-the-shelf microprocessor, a radio receiver, and a battery attached to a custom-printed circuit board, along with six electrodes implanted into the animals' optic lobes and flight muscles. Flight commands are wirelessly sent to the beetle via a radio-frequency transmitter that's controlled by a nearby laptop. Oscillating electrical pulses delivered to the beetle's optic lobes trigger takeoff, while a single short pulse ceases flight. Signals sent to the left or right basilar flight muscles make the animal turn right or left, respectively.

Most previous research in controlling insect flight has focused on moths. But beetles have certain advantages. The giant flower beetle's size--it ranges in weight from four to ten grams and is four to eight centimeters long--means that it can carry relatively heavy payloads. To be used for search-and-rescue missions, for example, the insect would need to carry a small camera and heat sensor.

In addition, the beetle's flight can be controlled relatively simply. A single signal sent to the wing muscles triggers the action, and the beetle takes care of the rest. "That allows the normal function to control the flapping of the wings," says Jay Keasling, who was not involved in the beetle research but who collaborates with Maharbiz. Minimal signaling conserves the battery, extending the life of the implant. Moths, on the other hand, require a stream of electrical signals in order to keep flying.

The research has been driven in large part by advances in the microelectronics industry, with miniaturization of microprocessors and batteries.