you need time to put away the gift before your sister enters and you need to be warned that your sister is coming
  • hang a bell to notify you that someone is entering and then put a door stopper to slow down the enterer you would hang the bell about 3" away from the door

  • put a trip wire to stop the enterer,
  • put a bucket on the door when it is open a few inches
  • put a buzzer on the door knob
  • use a spygear lazer alarm
  • put out a tripwire
  • buzzer under the doormat
  • put a horn under the door crack
  • put up a security camera
  • put an oil slick in front of the door
  • use a voicecommand system
  • put a finger scan lock

problems 3/10

different doorknobs

I decided to change the original design from a bell to a trip wire