Example Ultrasound Hardware

Figure 1 shows an untrasound spread spectrum implementation prototype which is essentially a Raspberry Pi, a low-power audio amplifier and a transducer that has good audio capability between approximately 5 kHz and 25 kHz. This is the spread-spectrum output device; the receive devices were PCs or mobile phones.

Figure 1 - Raspberry Pi Ultrasound Implementation

This prototype has been used to demonstrate robust information transfer in rooms aproximately 20 feet by 40 feet with output SPLs lower than 65 dB SPL - even when this prototype was put inside the speaker podium which had no direct path to the room volume.

Most speakers/transducers and microphones on consumer devices can accommodate most designs using frequencies between 5 kHz and 25 kHz (Nyquest criterion and other I/O capabilities limit descrete signal processing desings).

Michael A. Ramalho
Last Modified on :  October 14, 2019
Page Owner : Michael A. Ramalho, Ph.D.