University of Washington scientists create tiny sensor package that bees can carry

Keeping an eye on crops is getting to be a high tech job for farmers. Already farmers can use drones to fly over their fields and keep an eye on the temperature, humidity, and crop health. The catch is that the large drones have short flying times before they need to land and recharge. This has led researchers at the University of Washington (UW) to create a tiny sensing system that is small enough to be attached to the back of a bumblebee.

The sensor system has an internal rechargeable battery that can last for up to seven hours of flight time. When the bee returns to its hive at night, the sensor package would recharge and upload data. There were challenges with the bee sensor packs, namely GPS receivers use too much power, and insects can't carry much weight. This is what led the team to use the bumblebee because they are larger and able to carry a tiny battery that can power the system.

Bumblebees are also hive insects and return to their hive every night. The scientists are clear that in their testing they did follow "the best methods for care and handling" of the bees. The sensor backpack that the team designed weighs in at 102 milligrams, roughly the weight of seven grains of uncooked rice. Breaking that weight down, the battery is 70 milligrams of that weight meaning all the sensors and systems had only 30milligrams of weight left.

To determine where the bees were with no GPS equipment, the scientists set up antennas that broadcast signals from a base station across a specific area. A receiver in the bee backpack used the signal strength and angle between it and the bee to triangulate the bee's location. In testing on a soccer field, the team was able to detect the position of the bee as long as it was within 80 meters of the antennas.

Sensors in the backpacks include hardware for monitoring temperature, humidity, and light intensity. The entire system allows the bees to collect data and log the information with location. Data is uploaded at the hive using backscatter via reflecting radio waves transmitted from a nearby antenna. Current generation backpacks can only store 30 kilobytes of data. The team wants to create backpacks with live streaming cameras to send data to farmers in real-time in the future.