Flying drones can vary in size, whether they are cute little quadcopters that hold in the palm of your hand at giant passenger drones able to carry several people and their luggage. One thing that almost all of these have in common: the need for moving parts to make them take off. It's something that a new drone called ionocraft does not feel the need to adhere to.

Developed by researchers at the University of California, Berkeley, it is not just described as the the smallest flying robot ever madebut which flies without any moving parts: that is, without rotors, wings, or similar appendages. Instead, the insect scale robot relies on atmospheric ion thrusters that allow it to move in a completely silent manner.

"To understand how it works, imagine two asymmetrical – [such as] a wire and an electrode plate, "Daniel Drew, currently a postdoctoral fellow at the Department of Mechanical Engineering at Stanford University, told Digital Trends. "When a voltage is applied between the two, the electric field will be stronger in the vicinity of the wire depending on its geometry. If this field is strong enough, an ambient electron can be driven with enough kinetic energy to trigger the avalanche decomposition by impact ionization. There is now a stable plasma, purple in the dark, around the upper wire. The generated ions will be ejected from this plasma, drifting in the electric field towards the lower electrode. Along the way, they collide with neutral air molecules and impart dynamics, producing a clear surge. "

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By placing your hand under the lower electrode of the ionocraft, you feel the same sensation of accelerated airflow as if you placed it under a rotating propeller. This mechanism is called "electrohydrodynamic force", while the generation of ions is carried out using "corona discharge".

Drew suggests that the mechanical simplicity of the propulsion system should make these UAVs easy to manufacture. And their lack of moving parts or sound could make them useful for tasks such as monitoring and detection in the interior.

"The next step is immediately for controlled flight using onboard detection and an external controller, with wires for data transfer and power," he continued. "We think we are about to achieve this goal. The path to autonomous flight will require a low-mass electronics, being developed by a collaborator, a single-chip solution for computation and wireless communication currently being tested in our laboratory, as well as thin-film batteries with high energy density such as than those produced in the system. Berkeley Research Labs. "