(Credit: DC Fever)
Using the ioShutter.
Now, if your Pentax DSLR has a cable release socket, then you can use your iPhone to fire the shutter remotely but wired, and with even more software control capabilities including interval shooting, programmable bulb and sound/movement trigger etc. A nice and welcome Pentax alternative of course. And with many people are having iPhones nowadays, it could come in handy, provided that the user also brings along with the proprietary interfacing release cable that is to be purchased from the ioShutter altogether with the App.
Related:-
Remote Control Your Camera Using Android Device
The Pentax (Electronic) Cable Switches