Electronic monitoring unit for monitoring number of uses of cartridge

In a self contained electronic monitoring unit for monitoring and informing a user of the status of a cartridge designed to be used for a predetermined number of fills of a liquid container, the combination comprising:

• signaling means for providing at least first and second distinct human detectable output signals;
• use monitoring means for monitoring each use of a cartridge including liquid sensing means for sensing the presence of liquid during each time a container associated is filled with the cartridge and a pre-programmed integrated circuit responsive to the liquid sensing means for recording each use of the cartridge and for monitoring the occurrence, the imminent occurrence and the non-imminent occurrence of a predetermined number of uses, the monitoring means being arranged to provide outputs indicative that the predetermined number of uses has occurred, is imminent and is non-imminent, and for selectively operating the signaling means, the integrated circuit being programmed:
• a) to operate the signaling means to provide the first output signal when the output of the use monitoring means is indicative of the non-imminent occurrence of the predetermined number of uses to thereby inform the user that the device is operational and that the end of the useful life thereof is non imminent
• b) to operate the signaling means to provide the second output signal when the output of the use monitoring means is indicative of the imminent occurrence of the predetermined number of uses to thereby inform the user that the device is operational but that the end of the useful life thereof is imminent;
• and
• c) to operate the signaling means to provide neither the first nor the second signal when the output of the use monitoring means is indicative of the occurrence of the predetermined number of uses to thereby inform the user that the useful life of the device has ended.