Researchers from the University of Washington (UW) have created a sensor that weighs just 98 milligrams (1/10th the weight of a jellybean). Apart from creating such a lightweight sensor, they mounted the sensor on the back of a moth, turning it into an autonomous insect drone. Moreover, the sensor is highly durable as it can withstand a fall of approximately 84 feet or six storeys. Also, the sensor is designed to transmit environmental data such as temperature and humidity, wirelessly, and can last up to 3 years.

Researchers can create swarms of autonomous insect drones

The sensor was easily placed on the moth, like a small backpack. The sensor can be either deployed through small insects like moths and bees or through nano drones. Moths can navigate tiny, remote, and dangerous spaces without a heavy burden.

The moths will only serve as carriers of the sensors and will drop them when they approach their destination. This system would work like a standard drone delivery: Sensors would be perched on the backs of the moths. When the moths reach their destination, researchers can send a command via Bluetooth, and the sensor would unpin and fall to the ground. The lightweight sensors will then wirelessly transmit environmental data from the ground for up to three years.

Watch UW’s sensor carrying moth in action:

The UW team presented their research paper on 24th September at MobiCom 2020. A senior author of the paper, Shyam Gollakota, who is also a UW associate professor in the Paul G. Allen School of Computer Science & Engineering said that the inspiration came from the military’s supply helicopters; “We have seen examples of how the military drops food and essential supplies from helicopters in disaster zones. We were inspired by this and asked the question: Can we use a similar method to map out conditions in regions that are too small or too dangerous for a person to go to?”

The team stated that the battery of the sensor would be replaced by solar cells in future variations. The sensors could be mass deployed using several insects, creating a network across a farm, forest, or any other remote location.

The ingenious design of the ultra-light sensors

Apart from the nano form factor, the overall design aids in the delivery and durability of the sensor. The sensor is attached to the insect via a magnetic pin surrounded by a thin coil of wire. When the researchers send a wireless command to release the sensor, the thin coil generates a current which creates a magnetic field. Therefore, the magnetic field pops the pin from the insect’s back, sending the sensor to the ground.

The sensor is built with a small battery at the corner (the heaviest part). When the sensor is falling to the ground, it starts to spin from the corner, generating drag and slowing the descent. The drag along with the weight limits the descent speed at 11 mph. This makes sure that the sensor safely touches down.

Autonomous drone insect moth
Here, the sensor is placed on top of a penny (for size comparison). As stated, the battery is situated on the left corner of the sensor. Image credit: University of Washington

“This is the first time anyone has shown that sensors can be released from tiny drones or insects such as moths, which can traverse through narrow spaces better than any drone and sustain much longer flights.” Shyam added.

While using nano drones would allow researchers more control over where to place the sensors, using insects would give them an enormous operational range. The same team has also created a GoPro for beetles. This sensor delivery system through insects is a giant leap in the realm of insect drones. Although mosquito sized spy drones are still limited to fiction, insects may soon become the data collectors of the future.