Name that switch!

[hevans1944]

My thought...

A piezoelectric mic could be stuck on with tape to the side of your mouth/jaw the output fed to a small opamp which in turns slowly charges a capacitor which is bled to ground...

So for example just clenching will fire a spike but not enough to charge the cap, when you begin grinding the cap fills (adj time by potentiometer ) and then say a 555 triggers alarming you?

1 pot for time 1 pot for fine tuning sensitivity to the amplifier...

I like the thought of energy-harvesting a piezoelectric microphone as a motion sensor, but the output would be minucule IMHO. The silicone rubber hose, used as a sort of bridle with pressure sensor attached, seems most practical. Perhaps a cheap piezoelectric microphone (or crystal ear-bud if those are still available) would serve as an inexpensive pressure transducer. The OP could easily remove the tube from his mouth and place it under his chin periodically, which feature is what I like about it. Not too obtrusive and easy to apply and remove during the night if you want or need to do so.

The key will be the data acquisition system and associated signal conditioning. The pressure signals will be small changes and will need some "smart" software to pull them out of the "noise" for translation to something useful that can be recorded and related to bruxism.

As @KJ6EAD has noted, this is old technology that somehow failed to make the inventor fabulously wealthy after investing a lot of time and money to secure a patent and FDA approval for the sensing mechanism. Depending on where @anthonyadams lives, it may not be necessary to get the "guvmint" involved with this project. Here in the Nanny States, I am not so sure...

CYA disclaimer: I offer no medical or legal advice here. Please consult your healthcare professional for medical advice and your attorney for legal advice. Any electronic advice I offer is subject to the Terms and Rules posted on the website of this forum.

Hop

 

[cjdelphi]

Fair enough...

If you were able to use a small plastic tube to clench on without choking, maybe a pressure sensor like the one used in washing machines to detect when water fills up, tricky.

But with the piezo it's not really energy harvesting as the tiny signal is amplified...

 

[hevans1944]

Fair enough...

If you were able to use a small plastic tube to clench on without choking, maybe a pressure sensor like the one used in washing machines to detect when water fills up, tricky.

But with the piezo it's not really energy harvesting as the tiny signal is amplified...

Hadn't thought of using a washing machine fill-switch as a sensor. Should work, but as you said, tricky to set up. A linear pressure sensor would be better.

Sorry about the "energy harvesting" statement. I just assumed, since you were charging a capacitor with the piezoelectric microphone, that you intended it to also use it as a power source. My bad.

 

[cjdelphi]

Lol you'd have to do a lot of teeth grinding!

 

[hevans1944]

Lol you'd have to do a lot of teeth grinding!

Maybe not. They are doing a lot of wonderful things with ultra-low power electronics today. Nano-watt and pico-watt type stuff.

 

[AnalogKid]

A couple of peel-and-stick EKG electrode tabs seem safest to me. Yes, the signals are tiny, but so are EKG and EEG signals, and they've been used for decades. Lotsa high-gain, low-noise preamp parts out there; think moving coil phono preamp with different eq.

ak

 

[hevans1944]

A couple of peel-and-stick EKG electrode tabs seem safest to me. Yes, the signals are tiny, but so are EKG and EEG signals, and they've been used for decades. ...

... I've also been experimenting with EMG circuits. With a few electrodes taped to my jaw, I've been able to measure muscle activity. This approach is less intrusive than having something in your mouth, but it comes with a different set of challenges. Mainly, the signal produced by jaw muscles is very small, which makes it difficult to isolate.

As you can see, from reading the OP's comment in post #19, he has already tried this approach and found it lacking. EMG is much more difficult instrumentation than EEG.

 

[AnalogKid]

Well, maybe one "much" more. After my wife went through one I did some digging and whipped up a couple of flavors. Lotsa gain but not much bandwidth for a generic circuit, and probably "much" less bandwidth for this application. Without seeing his circuit we can only guess, but my guess is that the safety and convenience pluses more than outweigh an extra amp stage and a true IA front end.

ak