1. A BISTABLE SWITCH MECHANISM INDICATING THE DIRECTION OF ROTATION OF AN ASSOCIATED FINGER, SAID SWITCH CONSISTING ESSENTIALLY OF: A PAIR OF PIVOTED MEMBERS, EACH MEMBER BEING PIVOTED FOR LIMITED ARCUATE MOVEMENT; A SPRING CONNECTING PORTIONS OF EACH OF THE PAIR OF PIVOTED MEMBERS AND YIELDINGLY PERMITTING THE SHIFTING OF THE PAIR OF PIVOTED MEMBERS TO AND FROM A STABLE POSITION DESIGNATED AS AN ADVANCED POSITION AND A STABLE POSITION DESIGNATED AS A WITHDRAWN POSITION BUT NORMALLY URGING THE PIVOTED MEMBERS TOWARD SUCH A STABLE POSITION; A U-SHAPED SPRING IN A SLOT IN ONE OF THE PIVOTED MEMBERS, SAID SPRING HAVING TWO SPRING TIPS EXTENDING FROM SUCH SLOT, A SPRING TIP YIELDINGLY FLEXING DURING THE CONTINUED ROTATION OF AND ASSOCIATED FINGER IN THE DIRECTION CORRESPONDING TO THE POSITION OF THE BISTLE SWITCH, AND A SPRING TIP BEING ACTUATED TO SHIFT THE BISTLE SWITCH TO THE POSITION CORRESPONDING TO THE DIRECTION OF ROTATION OF THE FINGER WHEN CONTACTED BY THE INITIAL ROTATION OF THE FINGER THROUGH A CONTACT ZONE IN A DIRECTION OPPOSITE TO THAT CORRESPONDING TO THE POSITION OF THE BISTABLE SWITCH; AND AN ELECTRICAL SWITCH OPERATIVELY SHIFTED BY THE SHIFTING OF THE PAIR OF PIVOTED MEMBERS.