my project Capacitive Sensing LED dimmer 12F1822 via PWM

[Charlie]

@Charlie... my design is specifically designed to run on battery power. The PIC current drain should not change by much. Unless one starts trying to supply current via other pins.

Respectfully, that's simply wrong. Every different instruction uses a slightly different amount of current. Those current changes result in noise. Put a cap across the zener to resolve it. And if minimal current is your objective, you are wasting more in the zener than is used in the PIC. Use a regulator and use the PIC sleep capability to get down to minimal current. If you are really interested in parts count, have a look at some of the other PIC devices. The 12HV615 for instance - I've used this as a touch dimmer for LED lighting - can run off of 12V directly (well, through a resistor) because it has an integrated regulator. The method it uses, though, does still waste a little current.

[Heckler]

@Barry... building this just for hobby fun. And always enjoy using something I build myself. Probably just build a few for myself. Possibly thinking of using it as I teach electronics to Boy Scouts for the electronics merit badge. The final requirement is for them to build a project.

The touch sensor on my proto type is a bit of copper tape (Scotch #1245) stuck to my desk with regular scotch tape over the top as an insulator.

In the final I envision a small ckt board, say 1" x 2" or so, with a "touch" area for the button.

@Charlie... I did not know that there was an "HV" pic. Thats cool. Might have to take a look at getting a couple of samples.

So regarding the noise... A small cap across the power input is probably a good idea. What problems might the noise cause? Intermittent operation? I took a look with an o-scope across the power input (vss, vdd) and didn't see what I thought was a lot of noise (lot is a relative term though)

Yeah I am clear on the fact that a Zener supply is wastefull, but hey 2ma, though your point is well taken. I just don't have one of those LVD regulators on hand.

Again, just an exercise in understanding how to set-up and use the cap sense and maybe come up with a little fun project.

Really my signature line says it all for me.
Kinda like, why does one seemed determined to solve a rubics cube. (and no, I can't)
BUT I can easily waste? 4 or 5 hours trying to figure out the cap sense set up and coding on a little 8 pin pic