Should I use a loop instead of an If statement?

Question

I have a simple sketch that tests input from 2 touch sensors and outputs to 2 relays (if a sensor is touched, trigger the respective momentary relay). It has been a bit quirky to say the least. perhaps I need to adjust delays or adjust sensitivity of the touch sensors, but I feel that maybe the coding could be more efficient. Would using a WHILE or DOWHILE loop work better than an IF statement for this? It seems like there is a timing issue between the relay and the sensor. When I hit the sensor, the relay triggers immediately, but then it doesn't shut off right away. Also if both sensors are made at the same time, I am seeing only 1 relay trigger or neither. I am trying to eliminate the code as my failure point. I have the code printing to the serial monitor to show "Sensor 1 touched" or "Sensor 2 touched", and sometimes that triggers once and sometimes it will print multiple times.

int touchPin1 = 2; //Touch sensor 1
int touchPin2 = 4; //Touch sensor 2
int val_1 = 0; 
int val_2 = 0; 
int relayPin1 = 8; //Relay 1
int relayPin2 = 9; //Relay 2

void setup() 
{
  Serial.begin(9600);
  pinMode(touchPin1, INPUT); 
  pinMode(touchPin2, INPUT);
  pinMode(relayPin1, OUTPUT);
  pinMode(relayPin2, OUTPUT);

}

void loop() {
  digitalWrite(relayPin1, LOW);
  digitalWrite(relayPin2, LOW);
  val_1 = digitalRead(touchPin1);
  val_2 = digitalRead(touchPin2);  
  if(val_1 ==1)
  {
  Serial.println("Pad 1 Touched");
  digitalWrite(relayPin1, HIGH);
  }
  if(val_2 ==1)
  {
  Serial.println("Pad 2 Touched");
  digitalWrite(relayPin2, HIGH);
  }
  delay(100);
  //Serial.println();
}

Basically I am asking if there is a more efficient way to code this.

Touch Sensors: Adafruit Standalone Momentary Capacitive Touch Sensor Breakout Adafruit Part Number: 1374

Relays: SunFounder Relay Module for Arduino and Raspberry Pi 5V DC Trigger by HIGHLO (HIGH Trigger)

Answer 1

What you are lacking is the else concept:

• If a touch pad is pressed, then
  • Turn the relay on
• else
  • Turn the relay off

Rather than turn the relay off every iteration, you only turn it off if the touch pad is not pressed.

That can be written as:

val_1 = digitalRead(touchPin1);

if(val_1 ==1)
{
  Serial.println("Pad 1 Touched");
  digitalWrite(relayPin1, HIGH);
} else {
  digitalWrite(relayPin1, LOW);
}

If you want your messages to be more meaningful and not spam, then you can remember the previous state and only do things if the state changes:

static uint8_t oldVal1 = LOW;

uint8_t val1 = digitaRead(touchPin1);

if (val1 != oldVal1) {
    oldVal1 = val1;
    if (val1 == HIGH) {
        Serial.println("Pad 1 Touched");
        digitalWrite(relayPin1, HIGH);
    } else {
        Serial.println("Pad 1 Released");
        digitalWrite(relayPin1, LOW);
    }
}