expected `}' at end of input

Question

int scvVal = 6;
int drvVal = 9;
int sensorVal = A1;
void setup() { 
 Serial.begin(9600);
 pinMode(6, OUTPUT);
 pinMode(9, OUTPUT); 
 }
void loop(){
 sensorVal = analogRead(A1);
 Serial.print("Sensor Value: ");
 Serial.print(sensorVal);
 float voltage = (sensorVal*5.0)/1024.0; 
 Serial.print("Volts: ");
 Serial.print(voltage);
 float pressure_pascal = (400.0*((float)voltage-0.5))*1000000.0;
 float pressure_bar = pressure_pascal/10e5;
 Serial.print("Pressure = ");
 Serial.print(pressure_bar); 
 Serial.println(" bars");
 Serial.print("Pressure = ");
 {
 for(int a = 255; a>=0;a--)
 {
 analogWrite(6,a); 
 if (pressure_bar = 1600){
 analogWrite (6, a);
 if (pressure_bar > 1600){
 analogWrite (6, a);
 }
 for(int a = 0; a<256; a++)
 {
 analogWrite(6, a);
 {
 if(pressure_bar < 1600){
 analogWrite (6, a); 
 }
 for(int b = 255; b>=0;b--)
 {
 analogWrite(9, b);
 {
 if (pressure_bar == 1600){
 analogWrite (9, b);
 if(pressure_bar < 1600){
 analogWrite (9, b);
}
 for(int b = 0; b<256; b++)
 {
 analogWrite(9, b);
 { 
if (pressure_bar > 1600){
 analogWrite (9, b); 
 }
 }

• sempaiscuba: Welcome to Arduino:SE. Your life would be so much easier if you indented your code correctly. It would then be fairly obvious where the missing } should be.
• Đức Hòang: do you help me?
• chrisl: @Duc Hoang: Are you formatting your code correctly, that it is readable? Select in in the question editor and click on the {} button
• Majenko: Never before have I see such random use of brackets... ;)
• jsotola: do you help me? .... you have to start by helping yourself ..... read and understand the answers below ..... do not copy and paste code without thinking

Answer 1

Some guidelines for programming:

Start each statement on a new line

int scvVal = 6; 
int drvVal = 9; 
int sensorVal = A1; 
void setup() { 
Serial.begin(9600); 
pinMode(6, OUTPUT); 
pinMode(9, OUTPUT);
} void loop(){ 
sensorVal = analogRead(A1);
Serial.print("Sensor Value: "); Serial.print(sensorVal);
float voltage = (sensorVal*5.0)/1024.0; Serial.print("Volts: "); Serial.print(voltage);
float pressure_pascal = (400.0*((float)voltage-0.5))*1000000.0; 
float pressure_bar = pressure_pascal/10e5; 
Serial.print("Pressure = "); 
Serial.print(pressure_bar); 
Serial.println(" bars"); 
Serial.print("Pressure = "); { 
for(int a = 255; a>=0;a--) { 
analogWrite(6,a); 
if (pressure_bar = 1600){ 
analogWrite (6, a); 
if (pressure_bar > 1600){ 
analogWrite (6, a); } 
for(int a = 0; a<256; a++) { 
analogWrite(6, a); { 
if(pressure_bar < 1600){ 
analogWrite (6, a); } 
for(int b = 255; b>=0;b--) { 
analogWrite(9, b); { 
if (pressure_bar == 1600){ 
analogWrite (9, b); 
if(pressure_bar < 1600){ 
analogWrite (9, b); } 
for(int b = 0; b<256; b++) { 
analogWrite(9, b); { 
if (pressure_bar > 1600){ 
analogWrite (9, b);
} }

Use brackets and align them

.. so each pair of { and } is on the same column and align code with brackets to be indented 2, 3 or 4 spaces

int scvVal = 6; 
int drvVal = 9; 
int sensorVal = A1; 
void setup() 
{ 
 Serial.begin(9600); 
 pinMode(6, OUTPUT); 
 pinMode(9, OUTPUT);
} 
void loop()
{ 
 sensorVal = analogRead(A1);
 Serial.print("Sensor Value: "); 
 Serial.print(sensorVal);
 float voltage = (sensorVal*5.0)/1024.0; Serial.print("Volts: "); 
 Serial.print(voltage);
 float pressure_pascal = (400.0*((float)voltage-0.5))*1000000.0; 
 float pressure_bar = pressure_pascal/10e5; 
 Serial.print("Pressure = "); 
 Serial.print(pressure_bar); 
 Serial.println(" bars"); 
 Serial.print("Pressure = "); 
 { 
 for(int a = 255; a>=0;a--) 
 { 
 analogWrite(6,a); 
 if (pressure_bar = 1600)
 { 
 analogWrite (6, a); 
 if (pressure_bar > 1600)
 { 
 analogWrite (6, a); 
 } 
 for(int a = 0; a<256; a++) 
 { 
 analogWrite(6, a); 
 { 
 if(pressure_bar < 1600)
 { 
 analogWrite (6, a); 
 } 
 for(int b = 255; b>=0;b--) 
 { 
 analogWrite(9, b); 
 { 
 if (pressure_bar == 1600)
 { 
 analogWrite (9, b); 
 if(pressure_bar < 1600)
 { 
 analogWrite (9, b); 
 } 
 for(int b = 0; b<256; b++) 
 { 
 analogWrite(9, b); 
 { 
 if (pressure_bar > 1600)
 { 
 analogWrite (9, b);
 }
 }

Remove superfluous brackets

As you can see, you are having some superfluous/missing brackets. What you want is probably something like:

int scvVal = 6; 
int drvVal = 9; 
int sensorVal = A1; 
void setup() 
{ 
 Serial.begin(9600); 
 pinMode(6, OUTPUT); 
 pinMode(9, OUTPUT);
} 
void loop()
{ 
 sensorVal = analogRead(A1);
 Serial.print("Sensor Value: "); 
 Serial.print(sensorVal);
 float voltage = (sensorVal*5.0)/1024.0; Serial.print("Volts: "); 
 Serial.print(voltage);
 float pressure_pascal = (400.0*((float)voltage-0.5))*1000000.0; 
 float pressure_bar = pressure_pascal/10e5; 
 Serial.print("Pressure = "); 
 Serial.print(pressure_bar); 
 Serial.println(" bars"); 
 Serial.print("Pressure = "); 
 for(int a = 255; a>=0;a--) 
 { 
 analogWrite(6,a); 
 if (pressure_bar = 1600)
 { 
 analogWrite (6, a);
 }
 if (pressure_bar > 1600)
 { 
 analogWrite (6, a); 
 } 
 }
 for(int a = 0; a<256; a++) 
 {
 analogWrite(6, a); 
 if(pressure_bar < 1600)
 { 
 analogWrite (6, a); 
 }
 } 
 for(int b = 255; b>=0;b--) 
 { 
 analogWrite(9, b); 
 if (pressure_bar == 1600)
 { 
 analogWrite (9, b); 
 }
 if(pressure_bar < 1600)
 { 
 analogWrite (9, b); 
 } 
 }
 for(int b = 0; b<256; b++) 
 { 
 analogWrite(9, b); 
 if (pressure_bar > 1600)
 { 
 analogWrite (9, b);
 }
 }
}

Remove duplicate code

In the if statement, you perform twice the same code (both you send an analogWrite with the same value, so the code (from the for loops can be reduced to:

 for(int a = 255; a>=0;a--) 
 { 
 analogWrite(6,a); 
 if (pressure_bar >= 1600)
 { 
 analogWrite (6, a);
 }
 }
 for(int a = 0; a<256; a++) 
 {
 analogWrite(6, a); 
 if(pressure_bar <= 1600)
 { 
 analogWrite (6, a); 
 }
 } 
 for(int b = 255; b>=0;b--) 
 { 
 analogWrite(9, b); 
 if (pressure_bar <= 1600)
 { 
 analogWrite (9, b); 
 } 
 }
 for(int b = 0; b<256; b++) 
 { 
 analogWrite(9, b); 
 if (pressure_bar >= 1600)
 { 
 analogWrite (9, b);
 }
 }
}

Unclear

What is unclear why you first write an analog value, and directly afterward (in each if) you write the same value. I'm not sure what you really want here. Either you want to write to a different pin, or you want a delay (to have the value having some effect), I'm just not sure.

Answer 2

Look at your open brackets { vs closing brackets, }. You need the same number of each. If have this in the Arduino IDE and use CTRL-T, they are somewhat easy to find. I just looked, and I can spot them pretty easily.

int scvVal = 6; 
int drvVal = 9; 
int sensorVal = A1; 
void setup() 
{ 
Serial.begin(9600); 
pinMode(6, OUTPUT); 
pinMode(9, OUTPUT);
} 
void loop()
{ 
sensorVal = analogRead(A1);
Serial.print("Sensor Value: "); 
Serial.print(sensorVal);
float voltage = (sensorVal*5.0)/1024.0; 
Serial.print("Volts: "); 
Serial.print(voltage);
float pressure_pascal = (400.0*((float)voltage-0.5))*1000000.0; 
float pressure_bar = pressure_pascal/10e5; 
Serial.print("Pressure = "); 
Serial.print(pressure_bar); 
Serial.println(" bars"); 
Serial.print("Pressure = "); 
{ << bracket for what?
for(int a = 255; a>=0;a--) { << missing closing bracket
 analogWrite(6,a); 
 if (pressure_bar = 1600){ << missing closing bracket
 analogWrite (6, a); 
 if (pressure_bar > 1600){ 
 analogWrite (6, a); 
 } 
 for(int a = 0; a<256; a++) { 
 analogWrite(6, a); 
 { << wrong direction
 if(pressure_bar < 1600){ 
 analogWrite (6, a); 
 } 
 for(int b = 255; b>=0;b--) { 
 analogWrite(9, b); 
 { << wrong direction
 if (pressure_bar == 1600){ << missing closing bracket
 analogWrite (9, b); 
 if(pressure_bar < 1600){ << missing closing bracket
 analogWrite (9, b); 
 } 
 for(int b = 0; b<256; b++) { 
 analogWrite(9, b); 
 { << wrong direction
 if (pressure_bar > 1600){ 
 analogWrite (9, b);
 } 
} << closing bracket for loop