a yarn feeder including a storage drum which is held in a stationary manner on a housing , a rotatable winding tube disposed between the housing and the storage drum and having an outwardly facing yarn exit , and a bracket which is rigid with the housing . an opto - electronic sensor is provided at the bracket in alignment with a light inlet / exit zone . at least one wind deflector is provided between the yarn exit and the light inlet / exit zone . the deflector protrudes outwardly beyond the light inlet / exit zone to guide an air stream emerging from yarn exit away from the light inlet / exit zone .