I may not be phrasing this right, but basically how does the information translate from mere electronic impulse to interactive reality? How does the seemingly simple on/off nature of computer code result in such complex things as a high resolution image, audio, this website?
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Transducers. These are devices that turn one kind of physical phenomenon into another.
For instance, air pressure. Make a little metal sea!ed balloon with a flexible side. If the air outside is higher pressure than inside, the flexible part will bend a bit. Now fasten a special kind of wire on the flexible part, so it is stretched or squeezed by the flex. This wire has electrical resistance that changes depending on the stretch or squeeze. Put a constant current through the wire and measure the voltage, which will be low if the wire is low resistance, or high if high resistance. Run that voltage into a nifty circuit called an “analog to digital converter”; its output is a set of binary bits representing a number (e.g. 0011, or “3” in decimal) . Attach that ADC output to the input of your CPU, and run a program that reads that input, runs it through a math formula to map the voltage to pressure, and displays the number on your monitor: “Pressure = 1000 millibars”. Done!
Isn’t that simple?
And you can do the same thing with other physical phenomenon, like temperature, fuel flow, light intensity, ad infinitum.
For extra credit, figure out how to run this process in the other direction, so your computer can control the real world, instead of just sensing it. Hint: a circuit called “digital to analog converter” also exists.
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