EasyLog Counter, Event and State USB Data Logger - 

This standalone data logger can record events (detecting an input and storing the time and date), record state changes (similar to an 'event' but also recording when the input reverts back to normal) and count events (count the number of events that happen during a timed interval). Up to 32,510 events or state changes can be recorded and up to 32,510 timed intervals in event counter mode (with 65,536 events in each interval). The user can easily set up the logging rate and start time, and download the stored data by plugging the module into a PC's USB port and running the software (available as a free download from www.easylogusb.com). The data can then be graphed, printed and exported to other applications.