Parametric Speaker

Inspiration

The inspiration for this project was that the team had done some research into interesting and unique technology that we hadn't looked at before, and this was the most interesting option, so we decided to take the principles and develop them into a full project.

What it does

This speaker is designed to emit sound at an Ultrasound frequency of 40kHz, which isn't in the audible range for humans. However, once these sound waves reach a surface, they demodulate, and then they create audible sound at the location where they collided, which gives the impression that the source of the audio doesn't originate from the speakers. Another use is that if the ultrasound targets a person, the sound will seem as if it's coming from them, which means that we can then send secret audible messages to people that only they can hear depending on how large the range is. An application of this is to provide secret changing pins to members of staff so they can access pin-pads, or to receive secret notifications of security risks that don't panic the masses.

How we built it

We researched the components needed for the project and found sample circuits online. We then created the mount for the system out of foam board, and soldered the speakers to a board, connecting them to the 555 board.

Challenges we ran into

Using the incorrect rated capacitors
The initial breadboard was causing too much noise in the system, so we had to switch our system over to a soldered board
Trying to learn how the circuit should function
Wiring issues and reducing the noise of the circuit
Tuning using the capacitors to reach the desired frequency

Accomplishments that we're proud of

We have a sound output from the speaker system
We have made progress with each iteration of the system - Using Arduino to create a sound in the audible range from a Piezo speaker system / Implementing an audio jack into the system to change the audio to something that isn't chip tunes / Removing the Piezo speaker and implementing the Ultrasound system to then have an ultrasound output / Tuning the system with capacitors to then create a quiet audible system.

What we learned

Working with non-theoretical electricity provides new challenges
It's tough to try and tune audio you can't hear
Having a plan that extends over the entirety of the project is beneficial
Being able to quickly adapt keeps up progress to the project and enables us to continue working towards our goal