Relay and Liquid level sensor in IF statement

Projects Programming
1

Hello,

First of all thank you for reading me and the help. I tried to find solution on the web without success. I am new to arduino and the code.

I am trying to control a relay using a digital water level sensor.
The sensor is working fine I get 1 or 0 in the serial monitor based on the level of water from a small tank
Same thing for the relay if I control it itself I can activate or deactivate it without issue. My problem is in the combination of both relay and sensor within an IF ELSE statement.

I want the relay to deactivate if the sensor return 1 or activate the relay if the sensor return 0

I tried the code below. but basically the relay will not change if the sensor value change from 0 to 1 or 1 to 0.

Did I forgot something or is there a mistake in the code ?

FYI I am working with a 8 relays board and an Mega2560

#define RELAY_ON 0
#define RELAY_OFF 1

#define Relay8 31
#define Relay7 33
#define Relay6 35
#define Relay5 37
#define Relay4 39
#define Relay3 41
#define Relay2 43
#define Relay1 45
int Liquid_level=0;

void setup()
{
digitalWrite(Relay1,RELAY_OFF);
digitalWrite(Relay2,RELAY_OFF);
digitalWrite(Relay3,RELAY_OFF);
digitalWrite(Relay4,RELAY_OFF);
digitalWrite(Relay5,RELAY_OFF);
digitalWrite(Relay6,RELAY_OFF);
digitalWrite(Relay7,RELAY_OFF);
digitalWrite(Relay8,RELAY_OFF);

pinMode(Relay1, OUTPUT);
pinMode(Relay2, OUTPUT);
pinMode(Relay3, OUTPUT);
pinMode(Relay4, OUTPUT);
pinMode(Relay5, OUTPUT);
pinMode(Relay6, OUTPUT);
pinMode(Relay7, OUTPUT);
pinMode(Relay8, OUTPUT);
Serial.begin(9600);
pinMode(5,INPUT);
}

void loop()
{

Liquid_level=digitalRead(5);
Serial.print("Liquid_level= ");
Serial.println(Liquid_level,DEC);
delay(100);
if (digitalRead(Liquid_level) == HIGH) {
digitalWrite(Relay1,RELAY_OFF);
}
else{ // sinon
digitalWrite(Relay1,RELAY_ON);
}
}

Thanks in advance for your help.

2

I want the relay to deactivate if the sensor return 1 or activate the relay if the sensor return 0

Why do you talk about "the relay" when your code has 8 relays?

  Liquid_level=digitalRead(5);
  Serial.print("Liquid_level= ");
  Serial.println(Liquid_level,DEC);
  delay(100);
   if (digitalRead(Liquid_level) == HIGH) {

Is Liquid_Level a pin state, as the first statement in the snippet implies, or a pin number, as the last statement implies? It can not be both.

3

Thank you Paul.

Sorry for lack of the precision I mean by "the relay" Relay1

Regarding your second question, do you mean that I must replace :

if (digitalRead(Liquid_level) == HIGH)

By

if (Liquid_level == HIGH)

4

Regarding your second question, do you mean that I must replace :

if (digitalRead(Liquid_level) == HIGH)

By

if (Liquid_level == HIGH)

Personally, I think that that is obvious. But, just to be clear - yes.