Create a Sharp IR Distance Sensor class

[kevlam2706]

We used Sharp IR sensors in the last several years' robots. They provide an analog voltage which varies according to the distance to the nearest object. A graph of voltage-versus-distance is provided in the datasheets for these sensors.

It would be useful to have a wrapper class that knows how to interpret the values to turn into a distance, e.g. 2.3 volts = 17 cm, or whatever. Instead of using if/else or case statements, we could come up with a mathematical formula that fits the curve

Hint: people have already written some of these for Arduino - Google them up, find and port them over!

[kevlam2706]

Sharp GP2Y0A21YK0F has a "medium range" of 10-80 cm.

Datasheet: https://www.parallax.com/sites/default/files/downloads/28995-Sharp-GP2Y0A21YK0F-IR-Datasheet.pdf

[kevlam2706]

One possible approach:

1. Wire one of these IR sensors to a RoboRio's AIO port.
2. Write some simple code to read the sensor and output the value to the console or to a dashboard field.
3. Using a measuring tape, place an object at different distances from the sensor and record the sensor readings. For example, 10cm, 15cm, 20cm, etc.
4. Plot these values in an Excel graph. It should look similar to the graph in the datasheet.
5. Use a curve-fitting function in Excel to come up with coefficients of a polynomial.
6. Now write a sensor wrapper class that uses this formula to interpret the sensor value and return it in a method call.