Hy guys... I am using (trying to use) arduino uno with nextion display to watch batteries voltage and water and fuel tank in the boat... I am using a VDO resistors in the tank which goes from 10-180 ohms (10 when full, 180 when empty), so i added voltage regulator before to step down the voltage on 5V, and I am using 1 k resistor with the VDO tank sensor (resistor) to form a voltage divider... The problem is, when I power on the arduino and the display, everything works fine, but when i start to move VDO tank resistor it is giving me different analog input almoust every time on the same levels althougt the resistence remains the same... For example when it is full it shows 100%, and on the half it shows 50%... when I move the VDO resistor up and down few times, and i return it in the full position, the display shows let's say 86% instead of 100%... And then I move it on the half, it shows 24%... The VDO resistor is 100% good! I disconnected everything and just performed a measurment of an input value only with 1k ohm resistor and VDO resistor (sensor) and the same thing happens... First time on a half tank it flickers around lets say 80-90 and when i move it fast few times, it shows 120 on the half tank where it showed 80-90 last time... I tried taking down average measurments for smoothing, the same thing happens... Here is the code, it is quite simple... thanks in advance
float value;
float value2;
float value3;
int value4;
void setup() {
Serial.begin(9600);
pinMode(A0, INPUT); // Pin A0 set as input (batteries)
pinMode(A1, INPUT); //Pin A1 set as input (batteries)
pinMode(A2, INPUT); //Pin A2 set as input (water tank)
}
void mjerenje() // function for measuring batteries, diesel and water tank
{
value = analogRead(A0);
value = (value * 18 / 1023); // value conversion for batteries
value2 = analogRead(A1);
value2 = (value2 * 18 / 1023); // value conversion for batteries
value3 = analogRead(A2);
value4 = map(value3, 6, 160, 100, 0); //value conversion for water tank
value4 = constrain(value4, 0, 100); //constrains the value between 0 and 100
char buffer[10];
dtostrf(value, 3, 1, buffer); //converts a float to a char array with 1 decimal
Serial.print("t0.txt="); //command for printing in a text area (batteries)
Serial.write(0x22);
Serial.print(buffer); //prints out batteries value
Serial.write(0x22);
Serial.write(0xff); // end command
Serial.write(0xff);
Serial.write(0xff);
char bufer[10];
dtostrf(value2, 3, 1, bufer); //converts a float to a char array with 1 decimal
Serial.print("t1.txt="); //command for printing in a text area (batteries)
Serial.write(0x22);
Serial.print(bufer); //prints out batteries value
Serial.write(0x22);
Serial.write(0xff); // end command
Serial.write(0xff);
Serial.write(0xff);
Serial.print("t5.txt="); //command for printing in a text area (water tank)
Serial.write(0x22);
Serial.print(value4); // prints out water tank value
Serial.write(0x22);
Serial.write(0xff);
Serial.write(0xff);
Serial.write(0xff);
}
void loop() {
static unsigned long vrime; // delay every 5 seconds for debouncing
if (millis() - vrime >= 5000)
{
vrime += 5000;
mjerenje(); // calling the measure function every 5 seconds
}
}
