MIT's ongoing efforts to make flying drones ever smaller has passed a new milestone with the latest version of its Navion navigation chip. Essentially the brains for a drone the size of a honeybee, the chip measures just 20 square millimeters (0.03 sq in), which the researchers point out is about the size of a Lego minifigure's footprint.

Just as impressively, the chip demands just 24 milliwatts in power, around a thousandth of that needed to power a small, energy-efficient desk lamp. Energy-consumption is a huge issue for small drones and robots which need to carry an onboard power supply. The lower the energy use, the longer the machine can perform. And lower power needs means smaller batteries and hence smaller drones – which will doubtless be music to the ears of the Air Force Office of Scientific Research, who are co-funding the work along with the National Science Foundation.

Despite this, the researchers say the chip can process video at 171 frames per second while tracking inertial measurements to gauge its location in a 3D space – a capability that could prove useful in places where GPS isn't available.

Last year, the team announced it had managed to get power consumption down to 2 watts by combining algorithms and hardware on a single chip. But this was still well above the 100 milliwatts which is thought to be the practical threshold for power consumption in a miniature drone. To get under that, the team started again, designing a new chip from scratch, while keeping the approach of thinking about hardware and algorithms holistically.

The new chip compresses captured images to use less memory. The researchers have also made its algorithms more efficient by removing unnecessary computations. The 171 frames per second it captures marks a huge increase from the 20 fps of the 2-W chip.

"I can imagine applying this chip to low-energy robotics, like flapping-wing vehicles the size of your fingernail, or lighter-than-air vehicles like weather balloons, that have to go for months on one battery," says MIT's Sertac Karaman, a co-leader of the work. "Or imagine medical devices like a little pill you swallow, that can navigate in an intelligent way on very little battery so it doesn't overheat in your body. The chips we are building can help with all of these."

The team intends to demo the chip by adding it to a miniature race car with an onboard camera. Later, they plan to test it with drones, and then miniature drones. Whether this comes as welcome news will depend on your perspective. That may in turn depend on whether you're likely to be a direct beneficiary of the technology – or worried about being on the wrong end.

The chip will be presented this week at the Symposia on VLSI Technology and Circuits in Honolulu.

Source: MIT