If you’re trying to measure the strength of an insect’s leg response, you can’t poke it with your finger – the size difference between the two will be too large to do this with enough precision. However, a set of hand-controlled soft robotic microfingers can now do the job. Created by scientists at Japan’s Ritsumeikan University, each flat rectangular device is just 12mm long, 3mm wide and 490 micrometers (millionths of a meter) thick. Five of these are combined into a single device, which is basically a robotic arm with soft, flexible fingers. Each finger contains a balloon-like pneumatic actuator with a liquid metal strain gauge.

The user wears special sensors on their fingers that measure the speed, volume and direction of bending of the fingers. These data are transmitted in real time to the corresponding micro-fingers, causing them to bend accordingly. If they push an object pushing back, strain gauges measure the force with which that object does this.

During testing of the technology, microfingers were used to measure the reaction force of the legs of a live pill bug held upside down with a suction cup. The force measured was approximately 10 millinewtons, which coincided with previously calculated estimates. Now, it is hoped that with further development, this technology could be used not only in insect research, but also in other applications where a little “hands-on” approach is required.

“Using our voltage-sensing microfinger, we were able to directly measure the thrust and force of the pill bug’s legs and body, something that was previously impossible to achieve,” said lead researcher Professor Satoshi Konishi. “We hope our results will lead to further technological advances for microfinger-insect interactions, leading to human interactions with the environment on a much smaller scale.”