An always on button for the Canon Selphy CP910. The printer seems to work fine with the button on always depressed.
This was required for an instagram printer. The printer / driver would hang when sending two prints at the same time. To recover and continue printing, I use a wireless 433Mhz power adapter to physically turn the printer power on and off. The always on print ensures the printer turns back on automatically without user intervention.
Note that the picture shows a thinner version of this than is available for download. The thicker version was added to ensure it doesn't bend over time.