How do electronic sensors actually “sense” things
In: Technology
It really depends on the sensor, there lot of different things to send.
Many rely on changing a property of a circuit called “resistance”, which is a measure of how the circuit *pushes back* against a flow of electricity. If I take a battery and connect both ends together with a wire electricity will flow very quickly through the wire without achieving anything, this is called a ‘short circuit’. If I place a light bulb in the wire the light bulb resists the flow of electricity and makes light & heat, and the electricity flows slower, essentially. Any element you add to a circuit that slows the flow of electricity is a “resistor” in electrical-speak.
Now let’s make a resistor that can change it’s ability to resist in response to some outside input. I can create a dial resistor that goes from low resistance on one end and up to high resistance on the other end. That’s essentially a volume knob on a TV or stereo.
Instead of a dial, let’s make a resistor that changes it’s ability in response to light, in a dark room it has low resistance and in a bright room it has high resistance. That’s called a photo-resistor and is used in things like remote controls and dimming phone screens outdoors.
I can make a resistor that changes if it gets bent or changes shape, I could use that to detect damage to bridge or building for example, or put it below a button like on an ATM or a calculator to detect button presses.
I can make a resistor that changes if it gets warm or cold and use that as a thermometer.
I can make a resistor that changes if it’s upside down or side ways and use that to sense orientation.
I make a resistor that changes to sound… to radiation… to proximity (like in a motion sensor for an alarm system) … etc etc..
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