Related Clues:

• Light detectors
• They may be vital
• Burglar alarm features
• Items on space probes
• Electric eyes, e.g.
• They may be donated
• Some are vital
• Detection devices
• Periodicals
• Hearts, e.g.
• Hymn-playing instruments
• They detect heat or motion
• They can get pretty loud in church
• These can be vital
• Taste buds, essentially