laugh-o-meter
/lɑːˈfɒmɪtə/ /laˈfɒmɪtə/ /ˈlɑːfəʊˌmiːtə/(also laughometer)
noun
Any of various devices used to measure or indicate the volume (or another quality) of laughter, and hence to gauge the humour of a performance, joke, etc.
Origin
Early 20th century; earliest use found in North Adams (Massachusetts) Evening Transcript. From laugh + -ometer.