The S MINE 35, sometimes called the S-grenade or S-mine, was a small antipersonnel explosive device that could use an internal propulsive charge to fire itself a short distance into the air where it would explode. With a choice of several add-on mechanical or electrical triggers, it could be placed on the ground, buried in the ground, or, as on the Tiger tank, carried in a launcher tube.
Photographs of S-mines with attached mechanical triggers are provided in the U.S. War Department's Handbook on German Military Forces, section 5. The same description, without the photos, is provided by Lone Sentry. The S-mines used on the Tiger would have an internal trigger, screwed into a central threaded tube within the mine. In these photos, the base plate is on top and the trigger devices are screwed onto the end of this tube.
The launcher for S-grenades on the Tiger was an open metal tube of 3mm wall thickness. There was a thick strip welded across the back, with a central hole for the tube that protruded slightly from the base plate of the mine. The lead wires for the trigger extended from this tube. A spring was fixed inside the top of the launcher to hold the S-grenade in place. Near the front of the launcher there was a small hole; I don't know its purpose, but it may have been to aid in extracting a mine from the launcher.
The launcher was welded to a metal base, angled upwards at 30 degrees. The base, made of 4mm sheet metal, had bolt holes for attaching it to the mounts on the Tiger's hull. The vertical part of the support had 3 holes for the electrical connectors.
Three thumbwheels were provided for the electrical connections. They were threaded to bolts on a 5mm insulating board. This diagram shows the fixed parts, and the outline of the board.
This diagram shows the electrical components were assembled on the vertical fin of the launcher. The circuit board was mounted on the left side of the fin. There were two thumbscrews on this side, allowing the connection of the lead wires from the trigger. The rear thumbscrew was electrically connected to the launcher's body and thence to the hull of the tank, which provided the de facto ground voltage. The forward thumbscrew on the left side was insulated from the launcher's body but electrically connected to the single thumbscrew on the right side of the board. The signal wire from within the Tiger was connected to that thumbscrew.