Snap Circuits Led Secret Security System (for Tricks)

Step 1: Led Senser

Step 2: Trickster Led

Step 3: How to Use It

Put something in between the lighting up led and the senser and ask a volunteer to come and tell him to either take the thing out of the senser and put it back in or leave it how it is while you go out of the room then come back in and switch the switch connected to the led without them seeing you and if the led lights up they did not take it out to reset it press the button