Resistive Touch Sensor #electronic #experiment #technology

There were popular touch screen types before capacitive like the resistive touch screen. Here I have an 8B pencil and I'll make a solid strip of graphite on the paper. If I measure its resistance, it's around 1 kiloohm and gets a smaller if I go over a smaller trace. So, we fold it and place a voltage across it. Just for proving the point, let's put 120 V across it. Then we measure Ouch. Oh. I did have a battery. Trying again. So, I placed around 11 and 1/2 V across it, but anywhere I connect my probe to, it is like reading between two resistors that divide the voltage down. And if I slide the probe around, I change those values and read a different voltage. I put some tapes on these contacts to insulate them and placed a copper tape at the end of my probe so it can pick up and read the voltage. And if I put my copper tape on this trace, push my finger on it and slide over it with the voltage I'm reading on the scope, I can tell where my finger is on the strip. A simple one-dimensional resistive touch sensor. Now, make it 2D, make it transparent, and slap it on a display, and Bob's your uncle. You have a resistive touch screen.