Powah-1 and Powah-2

[asgard]

Here is a pretty simple pair of circuits.  The first one I call Powah-1.  As can be seen in the photos it is only about 0.5"x0.5".  This is a soft-switch on-off toggle.  Powah-1 can directly switch up to CMOS logic levels.  The difference in Powah-2 is that because of the protection barrier diode the logic is powered at 5.1V even though the PFET can switch 18V quite adequately.  The current draw on both devices at quiescent is at the measurability limit of my cheap B&K multimeter.  The other difference between Powah-1 and Powah-2 is the on-press of the button can be quite brief, while the off-press requires a full 3-second press to turn off the circuit.
The Powah-2 fits on a 0.8"x0.5" board.

If the pins are not connected the little boards can be mounted in various places and used as limit sensors for motion control, etc.

I did the materials costing and calculate (with the typical 4x materials cost value) the Powah-1 at $5.95, and the Powah-2 at $13.95.

Obviously for a power toggle a mechanical switch can be used, but a debounce circuit adjunct would require nearly the same amount of additional logic and cost.

Just thought I should throw it out here for your edification.
J.R.