Goals

The project has a goal of creating a simple USB ultrasound microphone capable of receiving up to 80kHz. 

As one of the primary goals is enabling you to perform 'acoustic cryptanalysis', a simple software program will be created enabling potentially interesting signals to monitored and decoded.

For example data may be 'exfiltrated' from a SMPS of a computer, by causing the processor to draw high or low amounts of power, causing the ultrasound emitted from the SMPS to change.  The signal from the SMPS will then be decodable by our software.

Schematic

This schematic depicts an STM32 microcontroller along with the MEMS ultrasound microphone.  It is powered and accessible by USB.   You will notice there is a 6 pin header to program the microcontroller.

PCB

The following image depicts the current positions of the components in kicad, before I've routed them.

I'm quite new to pcb design, especially with a microcontroller with so many pins!  So I'm going to spend a while positioning the components until I'm happy with their location prior to routing.

The routed PCB looks as follows:

I just sent it off to MacroFab for a prototype to be created today (16th April), hopefully I've not made any mistakes!