For the following questions refer to figure 1.1 of the attached doc. I'd like to use a ring electrode with a back-firing smt led centered in the ring. Drawing the schematic for the qtouch sensor, should I omit the electrodes leaving the resistors hanging and add the smt pad in PCB? Otherwise, I'm wondering how to represent the electrode symbol for the schematic. Would it have a pin to connect a trace to? I guess the footprint would have a smt pad with the diameter I want and then an inner diameter big enough to accommodate the led. Then place the back-firing footprint inside the ring electrode. My hurdle now is representing the electrode in the schematic.
On Sat, Jul 19, 2008 at 1:34 AM, DJ Delorie <[EMAIL PROTECTED]> wrote: > > For plain circles, smt pads are easier and better. > > If you wanted to do a resistive touch sensor with a circle with a ring > around it, you'd do the circle as a pad and a smaller circle (radius > == ring width) beside it. Then, when you lay out the board, add an > arc centered on the big pad, intersecting the small pad. Adjust the > angles with a text editor to come close to but not touch any traces > leading away from the center pad (or connect the center pad with a > via, and make the arc full circle. Make the solder mask for the > center pad big enough to expose the ring too. > > > _______________________________________________ > geda-user mailing list > [email protected] > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user >
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