Patent ID: 8324903

Claim:
A sensor ( 10 ) for use in conjunction with a canopy release mechanism, the sensor ( 10 ) having firing and testing modes and comprising: a detection sub-circuit ( 12 ) including a battery ( 20 ) and first and second electrodes ( 22 ), the detection sub-circuit ( 12 ) further including a first switch (S 1 ) having a closed position completing a circuit between the first and second electrodes ( 22 ) and an opened position with no circuit being completed between the first and second electrodes ( 22 ); a firing sub-circuit ( 14 ) connected to the detection sub-circuit ( 12 ), the firing sub-circuit ( 14 ) including a comparator ( 56 ) having positive and negative terminals and a comparator output, a capacitor ( 54 ) and a load ( 52 ) interconnected to the comparator output, a fixed reference voltage ( 62 ) connected to the negative terminal, a second switch (S 2 ) interconnected to the positive terminal, and two resistors, the second switch (S 2 ) having a closed position wherein the two resistors are placed in parallel whereby the fixed reference voltage ( 62 ) is not exceeded and there is no output from comparator ( 56 ), the second switch (S 2 ) further including an opened position wherein current flow at the comparator output is permitted; a test switch ( 38 ) and an associated test power source ( 36 ), closure of the test switch ( 38 ) effecting closure of the first and second switches (S 1 and S 2 ); a controller sub-circuit ( 16 ) connected to the detection sub-circuit ( 12 ) and including a microcontroller ( 70 ) and an EPROM ( 72 ), the controller sub-circuit ( 16 ) functioning to record data regarding the firing mode; whereby the firing mode is achieved when the test switch ( 38 ) is opened and sea water is present to complete a circuit between the first and second electrodes ( 22 ), the completed circuit delivering current to the firing sub-circuit ( 14 ), the opening of second switch (S 2 ), permitting current flow at the comparator output to charge capacitor ( 54 ) and fire load ( 52 ); and whereby the testing mode is achieved when the test switch ( 38 ) is closed to complete a circuit between the first and second electrodes ( 22 ), the complete circuit delivering current to the firing sub-circuit ( 14 ), the closing of second switch (S 2 ) preventing current flow at the comparator output, whereby capacitor ( 54 ) is not charged and load ( 52 ) is not fired, current being supplied to the controller sub-circuit ( 16 ) during the testing mode.