Capacitance sensing pads

I guess I wasn't clear. The symbol consists of a through-hole pad (which is

what the device connects to on the bottom layer), and a polygon around it.

The polygon has to be made in the top layer only, because that's where the

touch sensing happens. I can't make it with layer 17, because that would

create polygons on both top and bottom. For the buttons, I suppose I could

distort an SMD, but I also need to create W-shaped elements for the

"slider". If you're curious, here's the application note:

http://download.cypress.com.edgesuite.net/design_resources/application_notes/contents/capacitance_sensing___layout_guidelines_for_psoc_capsense___an2292_12.pdf

"David Moodie" <dgmoodie@onetel.com.cut_this_off> wrote in message

news:g2qoqd$phh$1@cheetah.cadsoft.de...

John Giddy wrote:

LGR wrote:

I'm trying to make some symbols to use as capacitive sensing buttons for

use with a Cypress PSoC Capsense chip. The Cypress application note

(AN2292) says to fill ground around the pads. I can't figure out how to

create a buffer area to keep the polygon from filling right over the

pads. Any ideas?

 

If the pads are made using SMD pads or through-hole pads, any polygon

drawn around them but named differently from the signals on the pads will

automatically have an isolation space around the pads.

If you draw the touch pads using polygons, you will just have to be

careful how you draw the ground polygon outline so an isolation space is

left.

John G.

 

If using two polygons then the inner polygon needs to have a lower rank

than the outer. See Help polygon, where there are a few lines on Rank.

You do not need to take special care about drawing the outer polygon.

The isolation will be set depending upon the isolation value of the

polygons, the higher value being used.

 

cheers

 

David

I guess I wasn't clear. The symbol consists of a through-hole pad (which is

what the device connects to on the bottom layer), and a polygon around it.

The polygon has to be made in the top layer only, because that's where the

touch sensing happens. I can't make it with layer 17, because that would

create polygons on both top and bottom. For the buttons, I suppose I could

distort an SMD, but I also need to create W-shaped elements for the

"slider". If you're curious, here's the application note:

http://download.cypress.com.edgesuite.net/design_resources/application_notes/contents/capacitance_sensing___layout_guidelines_for_psoc_capsense___an2292_12.pdf

"David Moodie" <dgmoodie@onetel.com.cut_this_off> wrote in message

news:g2qoqd$phh$1@cheetah.cadsoft.de...

John Giddy wrote:

LGR wrote:

I'm trying to make some symbols to use as capacitive sensing buttons for

use with a Cypress PSoC Capsense chip. The Cypress application note

(AN2292) says to fill ground around the pads. I can't figure out how to

create a buffer area to keep the polygon from filling right over the

pads. Any ideas?

 

If the pads are made using SMD pads or through-hole pads, any polygon

drawn around them but named differently from the signals on the pads will

automatically have an isolation space around the pads.

If you draw the touch pads using polygons, you will just have to be

careful how you draw the ground polygon outline so an isolation space is

left.

John G.

 

If using two polygons then the inner polygon needs to have a lower rank

than the outer. See Help polygon, where there are a few lines on Rank.

You do not need to take special care about drawing the outer polygon.

The isolation will be set depending upon the isolation value of the

polygons, the higher value being used.

 

cheers

 

David