A friend of mine holds an annual party where the theme is “pants”. For one of the years I added a custom light rig to a pair of pants. I used blue LEDs for the light sources and watch batteries for power. The big problem to solve was how to make them interactive. I wanted to make it so that when I moved the pants would flicker on and off. After a number of experiments I created a pressure activator from rubber suction cups and crossed wires. I attached the actuators to the bottom of my shoes. The suction cup held the wires apart, but when put pressure on it the suction cup collapsed, allowing the crossed wires to touch, completing the circuit and lighting up one leg of the pants (I made separate circuits for each leg).
The lights are shining on the left leg because my foot is fully on the ground. My right leg is not shining because my foot is off the ground. The switches I made were taped to the bottom of my shoes. Standing would activate the leg I was standing on, jumping or stepping would break the circuit. The pants were a total hit, because they seemed to have a life of their own.