To censor somebody’s speech or writing is to try to suppress it by preventing it from reaching the public. When guests on network TV utter obscenities, broadcasters practice censorship by bleeping them.
To censure someone, however, is to officially denounce an offender. You can be censured as much for actions as for words. A lawyer who destroyed evidence which would have been unfavorable to his client might be censured by the bar association.
A device which senses any change like changes in light or electrical output is a sensor. You car and your digital camera contain sensors.
A censer is a church incense burner.