Project On Ultrasound Gesture Detection

In this project, ultrasound around 24kHz was used to detect movement near an object. Waving a hand or other solid object near the source of the ultrasound (speaker) causes a shift in the frequency of the sound, which is then detected by a microphone. We detected characteristic shifts in frequency to determine whether motion was towards (push) or away from (pull) the microphone. Two modes of visual indication were used to display the results of the motion detection: blinking LEDs and a computer display. With the blinking LEDs, a different color LED would light up according to the direction of motion detected. In the computer animation, the waveform would be displayed on screen along with markings of which parts are pulls and pushes. Sections of the waveform that represent different motions would be marked as push or pull.

 Download Link:

Project on Thermistor Respiratory Monitor

For our project, we wanted to create a solution to a real-world problem. Many biomedical devices, such as commercially available respiratory monitors, are designed for the developed world and require a stable power-supply to operate. We wanted to implement a solution that is adaptable to different environments.
Our device uses several concepts we learned this semester in College. We use analog-to-digital conversions to sample readings from both the thermistor and the battery, pulse-width modulation to generate a signal for the speaker, and timers to switch between tasks. Our implantation also includes various analog circuitry for voltage regulation and signal amplification. Developing a robust and accurate respiratory monitor served to be a challenging, yet rewarding experience.

Download The Project: