Physical Computing at SVA IXD

An analog input is a measurable electrical signal with a defined range that is generated by a sensor and received by a controller. The analog input changes continuously in a definable manner in relation to the measured property.

The analog signals generated by some types of sensors must be conditioned by converting to a higher-level standard signal that can be transmitted over wires to the receiving controller. Analog inputs are converted to digital signals by the analog-to-digital (A/D) converter typically located at the controller. Analog-to-digital conversion is limited to a small range of DC voltage, so that internal or external input circuitry must change the character of non-compatible signal types to a DC voltage range within the limits of the A/D converter.

In this lab we wanted to try other variable resistors. I used a force-sensing resistor, and a photoresistor. When the photoresistor was used, if there was light, the LED will turn on, when I stopped the light from entering, the LED went off.

With the force sensing resistor same thing happened as you pressed the sensor, the LED will light up and, when you left it without pressure it will turn off.

With both sensors, I tried using two different resistors the 10K and 1K. With the 10K the LED could not be clearly seen when it lighted up. The values when measuring the voltage with the multimeter where the following:

With 10K, measuring across power and ground: 0.48V

With 1K, measuring across power and ground: 4.91V

When using the Arduino Serial Monitor you could see the differences in the numbers it showed as you changed the resistors. The biggest number it showed was 1023 and the lowest was 0 (with 1k resistor).