Hi guys! This is my first ever post here and my first ever program, so bear with me.
I'm trying to turn on a light by using an infrared sensor to find the speed of a car, and turn on a light if it is speeding to let the driver know.
I * a cough* tried cough :o to write a code, but it is not working(getting a "expected '(' before ';' token' error") and I need some help.
Here is my code:
int timer=0;
int IRPin=9;
int obstacle=HIGH;
int T;
int MS;
int LED=5;
int KMPH;
unsigned long currentMillis;
void setup() {
 // put your setup code here, to run once:
pinMode(IRPin, INPUT); //Defining inputs and outputs
pinMode(LED, OUTPUT);
}
void loop() {
 // put your main code here, to run repeatedly:
if (obstacle == LOW;) {Â //Means there is an obstacle
 currentMillis = millis(); //Start timer
 Â
 }
}
if (obstacle == HIGH;){ //No more obstacle
Â
}
MS=40/currentMillis; //Divide current time and pre-set distance to get meters per second
KMPH=MS*3.6; //convert to KMH
if (KMPH >= 40){
 digitalWrite(LED, HIGH);
}
}
All help appreciated, thanks in advance!
EDIT: Added my error name, as I forgot to.