Event-recording devices with identification codes

A method for reporting a physical or chemical state or event by using a device that changes a device state when exposed to the physical or chemical state or event, the method comprising:

• exposing the device to a first environment wherein the device comprises:
• a sensor for detecting the physical or chemical state or event wherein the sensor includes a first portion for latching onto one of a plurality of stops during an expansion of the sensor,
• a recording mechanism coupled to the sensor and recording the device state such that the device state changes upon occurrence of the physical or chemical event or a change in the physical or chemical state, and
• a transponder configured to transmit a signal indicating the device state when triggered by a wireless interrogation signal;
• probing the device with an interrogator to determine its current device state and thereby determine whether the first environment provided the physical or chemical state or event;
• saving the current device state as a saved device state;
• without physically resetting the device state, exposing the device to a second environment which potentially could provide the physical or chemical state or event to cause the device state to change;
• and
• probing the device with the interrogator to determine if its current device state is different from the saved device state and thereby determine whether the second environment provided the physical or chemical state or event.

A device for reporting a physical or chemical state or event, the device comprising:

• a sensor for detecting the physical or chemical state or event without using a power source wherein the sensor includes a first portion for latching onto one of a plurality of stops during an expansion of the sensor;
• a recording mechanism coupled to the sensor for recording that the physical or chemical state or event has occurred, wherein the recording mechanism allows recording of multiple physical or chemical events or state changes, each associated with a distinct device state;
• a tag that contains identification information that can distinguish said device from a plurality of similar devices;
• and
• a transponder, coupled to the recording mechanism and the tag, configured to transmit a signal indicating (i) the device state and thereby indicating the physical or chemical state or event and (ii) the identification information when triggered by a wireless interrogation signal.