This is a small demo schematic that was designed on a Samsung Galaxy Note using palmDraft for Android OS :
(right-click-open-in-new-tab to enlarge)
Here are some older schematics that were drawn using the palmOS version of palmDraft.
Top left: from Harry Konstas on a TRGpro (Montreal).
Bottom 2 schematics: from Luis Sifuentes Rosales on a m105 (Peru).
Click here to see a gallery of hand-drawn schematics.