Saying non credible af here, but in theory one could add a upwards facing shotgun shells on top of the helmet, triggered by a Camera/proximity sensor if it detects a drone/falling grande. Maybe add a gyroscope to check if the helmet is actually facing upwards before triggering. All in all unit cost could be below 250$

  • 6x 12 gauge shells with bird shot
  • Raspberry pi type controller
  • USB cam
  • Laser distance sensor
  • gyroscope
  • servo trigger