I have the pleasure to present a system that I developed and named "Mobile Terminal Ultrasonic Remote Control."
The mobile phone is used as remote management of devices (lights, doors) and access facilities through ultrasound waves.
The mobile must have only a program which emits control signals through ultrasound waves without altering the physical characteristics thereof.
These signals are sent through the speaker used to listen to music.
The prototype receiver uses simple components, starting with the microphone, which is electric.