Big bang: smart helmets prevent hearing loss

US Army helmet
U.S. Army 1st Lt. Elyse Ping Medvigy, a fire support officer with Delta Company, 1st Battalion, 12th Infantry Regiment, 4th Brigade Combat Team, 4th Infantry Division, conducts a call for fire during artillery training near Kandahar Airfield, Kandahar province, Afghanistan, Aug. 22, 2014. Credit: US Army photo by Staff Sgt. Whitney Houston/Released)