Ricoh released a SDK a while ago, see this thread:
Introducing Pentax Wi-Fi & USB Tether by PentaxForums.com - PentaxForums.com I haven't seen anything lately about Adam's program or the other project that someone on this forum was working on, so I don't know what the current status is.
Bad news: I did some research and the SDK only works for 645Z, K-1, KP and K-70 via USB. AFAIK, the developers of PKTether and PKTriggercord weren't able to figure out how to work with the K-3 (and it required putting your camera into debug mode, which my K-30 didn't like and I had to reinstall the firmware in my camera to get it to work at all)
Last edited by RGlasel; 02-28-2020 at 09:56 PM.