connecting 5v output to analog input to "test cables"

Projects General Guidance
6

OP's CODE

 int xlrPs = 52;  // XLR Positive Pin test send 
int xlrNs = 50;  // XLR Negative Pin test send
int xlrGs = 48;  // XLR Ground Pin test send
int xlrCs = 46;  // XLR Case test send
int xlrPr = A0;  // XLR Positive pin test receive
int xlrNr = A1;  // XLR Negative pin test receive
int xlrGr = A2;  // XLR Ground pin test receive
int xlrCr = A3;  // XLR Case test receive
int Pfail = 31;  // Positive pin test fail
int Nfail = 33;  // Negative pin test fail
int Gfail = 35;  // Ground pin test fail
int Cfail = 37;  // case test fail
int Ppass = 53;  // positive pin pass
int Npass = 51;  // negative pin test pass
int Gpass = 49;  // ground pin test pass
int Cpass = 47;  // case test pass
int Good = 41; // good cable led
int Bad = 43; // bad cable led
int pos = 0;  // variable for positive test
int neg = 0;  // variable for negative test
int gnd = 0;  // variable for ground test
int cas = 0;  // variable for case test (shielded cable)
int P = 0;
int N = 0;
int G = 0;
int C = 0;

void setup() {
  pinMode(xlrPs, OUTPUT);
  pinMode(xlrNs, OUTPUT);
  pinMode(xlrGs, OUTPUT);
  pinMode(xlrCs, OUTPUT);
  pinMode(Pfail, OUTPUT);
  pinMode(Nfail, OUTPUT);
  pinMode(Gfail, OUTPUT);
  pinMode(Cfail, OUTPUT);
  pinMode(Ppass, OUTPUT);
  pinMode(Npass, OUTPUT);
  pinMode(Gpass, OUTPUT);
  pinMode(Cpass, OUTPUT);
  pinMode(Good, OUTPUT);
  pinMode(Bad, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  digitalWrite(xlrPs, HIGH);
  pos = analogRead(xlrPr);
  if (pos >= 1020){
    delay(100);
    digitalWrite(Ppass, HIGH);
    digitalWrite(Pfail, LOW);
    P = 1;
  }
  else if (pos < 1020){
    delay(100);
    digitalWrite(Pfail, HIGH);
    digitalWrite(Ppass, LOW);
    P = 0;
  }
  digitalWrite(xlrNs, HIGH);
  neg = analogRead(xlrNr);
  if (neg >= 1020){
    delay(100);
    digitalWrite(Npass, HIGH);
    digitalWrite(Nfail, LOW);
    N = 1;
  }
  else if (neg < 1020){
    delay(100);
    digitalWrite(Npass, LOW);
    digitalWrite(Nfail, HIGH);
    N = 0;
  }
  digitalWrite(xlrGs, HIGH);
  gnd = analogRead(xlrGr);
  if (gnd >= 1020){
    delay(100);
    digitalWrite(Gpass, HIGH);
    digitalWrite(Gfail, LOW);
    G = 1;
  }
  else if (gnd < 1020){
    delay(100);
    digitalWrite(Gpass, LOW);
    digitalWrite(Gfail, HIGH);
    G = 0;
  }
  digitalWrite(xlrCs, HIGH);
  cas = analogRead(xlrCr);
  if (cas >= 1020){
    delay(100);
    digitalWrite(Cpass, HIGH);
    digitalWrite(Cfail, LOW);
    C = 1;
  }
  else if (cas < 1020){
    delay(100);
    digitalWrite(Cpass, LOW);
    digitalWrite(Cfail, HIGH);
    C = 0;
  }
  if (P + N + G + C == 4){
    digitalWrite(Good, HIGH);
    digitalWrite(Bad, LOW);
  }
  else if (P + N + G + C != 4){
    digitalWrite(Good, LOW);
    digitalWrite(Bad, HIGH);
  }
}

A neat idea to use the analog inputs - then you can see leakage or voltage drop over the wires.