Don Mcleish on the history of the PD
The PD came about because PK informed me that the MCE2S switch was likely an infringement on one of SF's patents. I wanted a clean way to access two levels of light output and it couldn't be via the tail switch as it had been. Push for momentary and t wist for lock was similar to the UI in the SF lights but with the addition of a second level via a deeper push or further twist. Initially it was used for two levels of current drive to the same LED. I took it down a new road with the LunaSol lights where one level was with a low level flood and the second level with a collimated beam. But as the LED's got brighter and approached 100 lumens, in my opinion it was time for three levels of output. I played with an additional contact in the PD design but felt it was not dependable or friendly in the momentary mode and only reasonable in the twisty mode. Fortunately three (or even more) levels of output could be accessed with a quick on-off-on cycling either in mom...