FSR LED System

Projects Programming
1

I also posted this in the sensor forum, let me know if crossposting is not allowed

Hi all,

I am building a small project that has 3 LEDs and an FSR sensor. Essentially, I want each LED to light up SEPARATELY as more pressure is applied. Here is what I want in pseudo code.

0-50 - no LEDs are lit
50-400 - only first LED is lit
400 - 700 - only second LED is lit
700 - 1000 - only third LED is lit

my serial print is working, and the FSR is projecting a nice range from 0-900

my code at the moment just lights up the first two, and the pressure controls brightness for some reason, even though I never defined brightness as a value.

HERE IS MY CODE

int sensorPin = A0;
int ledPin1 = 13;
int ledPin2 = 11; 
int ledPin3 = 10; 

int sensorValue = 0;
int noPressure = 50; 
int lowPressure = 400; 
int goodPressure = 700; 
int hiPressure = 1000;


void setup() {
 pinMode(sensorPin, INPUT); 
 pinMode(ledPin1, OUTPUT); 
 pinMode(ledPin2, OUTPUT); 
 pinMode(ledPin3, OUTPUT); 

 Serial.begin(9600);

}

void loop() {
 sensorValue = analogRead(sensorPin); //reads pin value, assigns it to sensorValue

 Serial.println(sensorValue);

 if (sensorValue <= noPressure)
 {
   digitalWrite(ledPin1, LOW); 
   digitalWrite(ledPin2, LOW); 
   digitalWrite(ledPin3, LOW); 
 }

 if (sensorValue < lowPressure)
 {
   digitalWrite(ledPin1, LOW); 
   digitalWrite(ledPin2, LOW); 
   digitalWrite(ledPin3, HIGH);
 }

 else(ledPin3, LOW);

 if (sensorValue < goodPressure) 
 {
   digitalWrite(ledPin1, LOW); 
   digitalWrite(ledPin2, HIGH); 
   digitalWrite(ledPin3, LOW);
 }

 else(ledPin2, LOW);

 if (sensorValue < hiPressure) 
 {
   digitalWrite(ledPin1, LOW); 
   digitalWrite(ledPin2, LOW); 
   digitalWrite(ledPin3, HIGH);
 }

 else(ledPin3, LOW);
}
3

Hello @georgiaes,

georgiaes:
I also posted this in the sensor forum, let me know if crossposting is not allowed

It is not. Other thread removed.

4

Assume sensorValue is 23. Start at the first if statement...

...
 if (sensorValue <= noPressure)
...

Work your way down through the code. Try to determine how execution flows (which then-clauses run because the if-condition is true). I find a print out and pen to be useful for such things.

Can you see why the program is doing what it is doing?

5

Delta_G:
Please read the "How to use this forum" thread at the top of any of the message boards. In the coding and electronics world, a good starting place is always to read the instructions.

That would also help you a lot with your current dilemma. If you'll look at some code examples, you'll notice that NONE of them look like

else(ledPin3, LOW);

Uh oh. How do you have things wired up? Do you have resistors on those LEDs?

Hi, thanks for the response. I will review other coding examples, I am pretty new to programming. Do you have any suggestions on how I can apply (properly notated) if/else statements to my project?

I am confident in my wiring, I have resistors on each LED and I have run my current set-up through a simpler project to see if each of the LEDs were working properly.