Facebook
Google
GitHub
Linkedin
Hey, im just wondering if anyone has seen or have experience about lateral axis sensors using capasitance (for measuring angle between two metal plates)?
Last edited:
Capasitance angle sensor
- Thread starter William.Joh
- Start date
Got a source for proof of concept?
Air-spaced tuning capacitor for AM radio?
I asking for an industrial application. I suppose there are many ways to derive an angle from a capacitance but noise and tiny distance between plates come to mind as the limiting factors. On the other hand, I can see these devices being very precise hence the radio tuning capability.
A 3-plate sensor can null-out the effects of plate spacing.
How? I imagine the angle between the middle plate and the left plate will be proportional to the middle plate and the right plate where they add to a coefficient of 1. I'm just trying to get my head around how this would actually be measured. Some kind of differential amplifier?
Here imagine the rotating electrode is energized with a signal and the fixed plate is actually 2 plates with a gap for the moving one to slide into.
The two fixed plates connect to a Transimpedance amplifier that converts the coupled capacitive signal to a voltage.
Now the axial motion of the electrode is diluted, having far less impact on the reading.
If you add another set of electrodes on the other side and make the reading differential, even better.
Since the sensing electrodes are at virtual ground, you can shield the thing with a grounded cover with no loss of sensitivity.
Driving the plates with two signals 180 degrees out of phase is a cool trick, but then you need a synchronous demodulator.
Last edited:
