//  Adapted from: rx_tx01  Robert Hart Mar 2019.
//  Program to use transmit-receive across space between two conductors.
//  One conductor attached to pin D10, one to A0
//
//  
//  Signal varies with electric field coupling between conductors, and can
//  be used to measure many things related to position, overlap, and intervening material
//  between the two conductors.
//




int read_high;
int read_low;
int diff;


void setup() {
pinMode(D10,OUTPUT);      //Pin D10 provides the voltage step
Serial.begin(9600);
}

void loop() {


   digitalWrite(D10,HIGH);              //Step the voltage high on conductor 1.
   read_high = analogRead(A0);        //Measure response of conductor 2.
   delayMicroseconds(100);            //Delay to reach steady state.
   digitalWrite(D10,LOW);               //Step the voltage to zero on conductor 1.
   read_low = analogRead(A0);         //Measure response of conductor 2.
   diff = read_high - read_low;       //desired answer is the difference between high and low.

Serial.println(diff);
delay(100);

}