EDIT: This is a continually updating post of our various hardware iterations. You can track the changes and see how our product progresses from breadboard to manufacturing at scale.
Updated on November 4, 2012
We just received our second prototype, substituting the breadboard prototype with our own PCB.
We decided to keep using the same Microchip ADK kit and only design the analog board with a flat connector. Separating the analog and digital circuits will enable us to iterate faster – for example, if we want to switch to a different microcontroller.
Updated on July 4, 2012
The first version of our hardware is up and running.
By this we mean that we are able to connect our board to an Android phone through USB (using the Microchip ADK Starter's kit) and sample at 40,000 samples per second, including real-time signal analysis and classification. Our goal is to reach ultrasound frequencies (~ 120 Ksps).
We are using the PIC24F microcontroller that comes with the kit and added a Texas Instruments ADC (Analog Digital Converter) that should be able to reach 500 ksps. Our current bottleneck is in sampling and transmitting the data to Android. It's a combination of the microcontroller's abilities and the fact that Android phones only support USB full-speed.
Next up is to increase the sampling rate by tweaking the firmware and validating the analog circuits – data integrity above all.