Hi Ashley
You need an S or L type Cable Release, in any convenient length. There is a photo of the connecting end at ....
.... which is in .... Contax User Forum » Contax SLR C/Y-mount » Yashica Lenses with C/Y mount » Yashica3.5-5.6/28-210
There are older Contax Infra-red and Radio-remote systems which crop up second-hand every now and again. You can see an ex&le of these (in German) on Dirk's Brochure pages.
See the 1982 System Brochure - page 19.
I have made several systems for Contax owners that used different trigger mechanisms. Some based on ultra cheap Toy Radio Control cars ( with the receiver stripped out) and others on car-boot sale bought Infra-red devices.
All that is required is an isolated push-to-make switch (e.g. relay) connected to the cable that attaches to the camera. I used a surplus cable release cable on some, discarding the (faulty) push switch. On others, I broke into the cable release cable with a miniature male/female connector, preserving the original cable push switch function. It only requires simple soldering of the 2 core cable.
I do remember accidently running off a roll of film once when one of the prototype radio devices was not shielded and a near-by parked Radio-cab took over control of my camera! The same device proved excellent later controlling the camera at over 100 yards from my hide.
Send private message if such a project appeals to you.
Cheers, Kyocera Kid.