Amazon has filed a patent to build drone propellers that can emit warning noises and certain phrases.
The ecommerce giant is interested in using drones to deliver parcels to people’s homes and offices, cutting out delivery companies like FedEx and DHL.
Spotted by The Register on Thursday, the patent filing has two elements to it.
One involves using drone propellers to alert people on the ground of the drone’s presence, possibly by shouting phrases like “watch out” at them.
The patent reads:
Suppose, for instance, that the AAV were delivering an inventory item to a location. Upon approaching the location, the AAV determines (e.g., based on a video signal fed as an input parameter to the controller via a camera) that a person is situated at or near an intended or a suitable landing area corresponding to the delivery location. Such an input parameter may satisfy a flight condition corresponding to an audible communication, such as a “Watch out!” warning message. Accordingly, the controller may determine and cause to implement modulations of the rotational speed of a propeller, thereby causing the propeller to produce a series of sounds that are audibly perceptible as “Watch out!”
A diagram in the patent shows that Amazon also thinks it would be possible to use LEDs in/on the propellers to convey messages like “Hi.”
The other element involves developing drones with noise-cancelling propellors rotating in different directions. In the patent, Amazon gives an example of a drone with two propellors, stating that one would generate lift, while another could cancel out noise.
The patent reads:
In some cases, an audio sensor (e.g., a microphone) located near the first propeller may detect the noise generated by the first propeller. A controller may be in direct or indirect communication with the audio sensor. The controller may be configured to receive a signal representing the noise detected by the audio sensor. The controller may also be in direct or indirect communication with the second propeller, and may cause the second propeller to produce anti-noise sound that cancels the noise generated by the first propeller.