I'm attempting to build a project using the Capacitive Sensing Library. As suggested in the last paragraph of "Grounding and other known issues" section, I put a foil ground plane under the plates I'm using.
However, I get highly variable results. It was very difficult to get the copper wire to solder to the aluminum plates I am using. First, I cut the top and bottom off of an aluminum can then cut that cylinder so that I could flatten it out. I cut that into plates 3 cm by 3 cm. Then I sanded until I had a corner with no paint then tried to solder to the bare section. It took several tries, but eventually to the wire soldered to the plate.
It easily broke off. I used a 25 watt soldering iron. Would it help if I step up to my 45 watt iron? Should I cut the corners so that I could crimp before soldering? Is the plate just too big so that it dissipates the heat too quickly? I've also tried soldering to aluminum foil, with the same result. I've got some thin steel that I could try, if that would solder better. I'm seeking advice before I experiment further.
FYI: I tried the example program for this library (first paragraph), with no changes. I taped the plates down with a wire in contact with the bare corner on the plate, and used 41 MΩ resistors. The three plates that I tried were highly variable and seemed to perform better when they had better contact with the wire. That is why I need to know how to get a good solder connection.