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The technology used in bomb and shell fuses could help baseball players and
coaches to record ball speeds (WO 01/79858). Single-chip fuses use a simple
Doppler radar circuit to detect a target and detonate the bomb just before
impact. Now Sports Sensors of Cincinnati has built a similar chip into a
wristwatch-like device designed to be worn by a batter. The chip times radar
reflections from objects up to a metre away and calculates the ball’s speed,
which it displays on an LCD on the back of a player’s glove.