SX-70 cable release prototype
The SX-70 shutter mechanism is triggered by metal contacts - all a cable release does is jump those contacts in the shutter housing, and move the contact point to the remote trigger (the toggle switch, in this case).
This is an early prototype I made to test that. It's pretty idiot-proof to make your own cable release, hell you could get away even with sticking two stripped wires in the socket and touching them when you're ready to expose.
SX-70 cable release prototype
The SX-70 shutter mechanism is triggered by metal contacts - all a cable release does is jump those contacts in the shutter housing, and move the contact point to the remote trigger (the toggle switch, in this case).
This is an early prototype I made to test that. It's pretty idiot-proof to make your own cable release, hell you could get away even with sticking two stripped wires in the socket and touching them when you're ready to expose.