Assertion: optical keyboard | /r/Desires | at least 2 beams
Facets:
value: to determine the actuated key
type: PURPOSE
Source sentences:
text: Most optical keyboards require at least 2 beams (most commonly vertical beam and horizontal beam) to determine the actuated key.
text: Most optical keyboards require at least 2 beams (most commonly a vertical beam and a horizontal beam) to determine the actuated key.