q output of flip flop 76 is also fed through a delay circuit 79 to a solid state relay 80 which is used to energize a light bulb 81 which is located within the space enclosed by the door the q output of the flip flop 76 is fed to the clock input of a second flip flop 83 briefly the function of the flip flop 76 may be thought of as determining whether the circuitry is operative or inactive whereas the function of the flip flop 83 is to indicate when the circuitry is operative whether the door is to be driven in a first direction which may be open or a second direction which may be close the q output of the flip flop 83 is connected to a second input of the and gate 78 the q output of flip flop 83 is connected to the second input of and gate 77 as well as to the data input of a latch flip flop 96 which controls the counter circuit 33 to indicate whether the counter is to count up or to count down if the q signal is a 1 the counter circuit count increments and if the signal is a 0 the counter circuit decrements both incrementing and decrementing being responsive to pulses sensed by the transducer 30 the q output of the latch 96 is.