So for a recent science fair i built a theremin based medical monitor. It uses the human body as an external capacitor and the chest movements of breathing are recorded with capacitive sensing. Two oscillators were constructed, and the capacitance changes of the oscillators change the frequencies. I plotted these frequency changes on Audacity. I built it with nand gates and TTL chips on a classic breadboard. Now, i’m looking to improve its sensitivity and make it more stable. Perhaps arduino is an option, but i really have no idea as to where to go. How can I increase the sentitivity, and finalize my project? How do i get started with arduino (i have no experience with arduino). Any tips, advice, help would be much appreciated
If you search google for thereminvision you should come across sites and a pdf document by Terry Fritz where he used (CMOS) 555 chips operating at megahertz frequencies to detect distances of robots by heterodyning. Probably similar to your method. So it may help you if you increase the operating frequency.
The main issue that you will have using a theremin approach is thermal drift. It is a bit complicated how to over come this and those in the theremin community that talk big never demonstrated any method that solves this. If you want good sensitivity you want to use a LC oscillator approach. Theremins use changes in capacitance to the sensor as the mechanism that creates the proximity effect. I would suggest you experiment with the Theremaniac assembled board for $99. You can find it on ebay. My interest in the theremin is as a musical instrument and how the early models had the sound of a lady singing. I may be the only one on the planet today that has figured it out. I can’t play but listen http://www.oldtemecula.com/theremin/tw/ … oice5r.mp3 450k
Good Luck,
Christopher
Edit:
Here is a modern day open source Arduino approach to theremin building, maybe the “best” DIY digital theremin.
