Multiple if statements

Thanks in advance for your help.

So I’m working on a pressure sensor. The idea is that when the pressure sensor gets to a certain value, say 10 AND then decreases sharply after it has gotten to 10, activate the buzzer. (So it’s like, I pump my car tire to 10 and I want to know if there is a leak)

I just for the life of me can not make this happen. I know I’m just missing something very small but I will greatly appreciate any help.

Below is my code:

#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

// These constants won’t change:
const int analogPin = A0; // pin that the sensor is attached to
const int ledPin = 13; // pin that the LED is attached to
const int threshold = 5; // an arbitrary threshold level that’s in the range of the analog input
const int buzzer = 9; // pin that the buzzer is connected to.

void setup() {
// initialize the LED pin as an output:
pinMode(ledPin, OUTPUT); // initilizes the pin as an output.
pinMode(buzzer, OUTPUT); // Set buzzer - pin 9 as an output

// initialize serial communications:
lcd.begin(16, 2);
lcd.print (“Pressure in kpa”);

void loop() {
// read the value of the pressure sensor:
float sensorValue = analogRead(analogPin);
// int kpa = (((sensorValue5)/1024)(120/5)-116); // 116 was subtracted to equilibrate the sensor
int kpa = ((sensorValue * 5 / 1024) * (15 / 5) * (6.894 / 1) - 10); //
// if the analog value is greater than whatever threshold we use , turn on the LED:

if (kpa > threshold )

digitalWrite(ledPin, HIGH);
digitalWrite(buzzer, HIGH);
tone(buzzer, 1000); // this controls the picth of the sound. (Hz)
} else {
digitalWrite(ledPin, LOW);
digitalWrite(buzzer, LOW);
noTone(buzzer); // Stop sound…

// print the analog value:
delay(1); // delay in between reads for stability
lcd.setCursor (0, 1);
lcd.print (kpa);



Are the kpa values on the LCD correct?

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[code] Paste sketch here. [/code]


How fast a leak? If you pump up to 200kPa and it takes 10 minutes to fall back to 190 kPa, is that a leak?