@@ -16,9 +16,15 @@ In short, these solutions seem cool, but complicated, and I need to take some mo
...
@@ -16,9 +16,15 @@ In short, these solutions seem cool, but complicated, and I need to take some mo
- adc resolution -> bar width / spacing
- adc resolution -> bar width / spacing
- grounding, stack setup, tx pads, rx pad(s)?
- grounding, stack setup, tx pads, rx pad(s)?
## Understanding the Phenomenon
It's good to try to get a grounding on what's really going on. To get the basics in order, I go [here](http://hyperphysics.phy-astr.gsu.edu/hbase/electric/pplate.html).
Capacitance is $C = \frac{k * e * A}{d}$ where $k$ is the relative permittivity of the material between the plates, $e$ is a constant making $k * e = 1$ in air, $A$ is the area of the plates and $d$ is the separation of those plates.
Some quick thoughts
Some quick thoughts
- do static tx / rx pads. reference is metallic thing that moves between them, changing the permeability of space between them
- do static tx / rx pads. reference is metallic thing that moves between them, changing the permeattivity of space between them
- bc capacitance is C = \frac{k * e * A}{d} where E is constant, A is area, and K is relative permeability (k ~= 1 for air)
- bc capacitance is C = \frac{k * e * A}{d} where E is constant, A is area, and K is relative permeattivity (k ~= 1 for air)
- 'metallic thing' can be double-sided pcb w/ sawtooth or sine pattern to read
- 'metallic thing' can be double-sided pcb w/ sawtooth or sine pattern to read
- can do spreadsheet maths for tx / rx areas, see what total capacitance range will be (1pf -> 15pf?)
- can do spreadsheet maths for tx / rx areas, see what total capacitance range will be (1pf -> 15pf?)
- can figure apparent rise-time calculator, probably?
- can figure apparent rise-time calculator, probably?
