A projectile launch detector, including a body, a mast and a blade rigidly connected to the mast; the mast being capable of sliding between a retracted configuration and a deployed configuration, and capable of pivoting between a first and a second angular position. The detector may further includes a first elastic return element to return the mast to the deployed configuration relative to the body; and a first associated sensor; and a second elastic return element to return the mast to the first angular position relative to the body; and a second associated sensor.