Abstract: An event sensor circuit monitors power consumption patterns of a device to determine occurrence of particular operations by the device. In response to detection of one or more particular operations the event sensor signals an alert generator to generate an alert. The system may be implemented within a replaceable battery pack or in an add-on package to monitor power consumption of the device and generate an alert. The event sensor circuit and alert generator utilizes a microprocessor which can be programmed to accommodate pattern detection in a variety of devices. The event sensor circuit and alert generator can be used as an alternative or supplemental alert signal source for a device and can be user selectively enabled or disabled and user selectively set to provide a variety of alert signals. The alert generator can be user programmable to provide a fully customized alert.