The a common sensor that I see in everyday life is the light sensor. As we come home from a hard day of work and approach our door we are often invited by light turned on by a sensor. We also put light sensors into our electrical outlets to provide light as we walk around in the dark. When we enter the grocery store motion detection opens the door for us. These senors are of then using sound or light sensing technologies. As we walk into the grocery store the change in light value will trigger the sensor to provide a function; in this case it is opening the door.
Nowadays, whoever has a smart phone, carries sensors where ever they go. The obvious sensor in the these smart phones is the touch screen. When we touch these screens we change the state. One method to how they accomplish this is capacitance. A layer of conductive material holds a charge and when we touch the screen the state changes on contact. Resistance is another method where pressure from our fingers cause conductivity where the resistive layers come into contact which then changes the resistance which effects the input. Accelerometers are another sensor found in smart phones. This can allows the phone to know it’s orientation. This can be used for gaming or simply adjusting the view to better suit us. When using GPS function, the accelerometer sends data to the GPS enabling the phone to know it’s directional orientation relative to the cardinal directions. Most accelerometers have embedded micro crystal structures that create a voltage based on stress from movement. The circuitry interprets this change in voltage and translates in in data which the device can use.
I am interested in movement. What comes to mind is an IR triggered zoetrope. As the motor spins a plate, each pass trips the IR sensor causing an LED to blink creating a frame. So this would simplify the syncing process of the RPMs and the rate of flashes. With the turn of a knob the RPM of the motor will increase and the rate of flashes would change accordingly.