Read PWM input with Arduino. I used it to check the pulse lengths on a Futaba RC receiver to set the endpoints.

gistfile1.ino

const int pin = 2;
const int numSamples = 1000;

volatile unsigned long microseconds;
volatile byte index = 0;
volatile unsigned long results[numSamples];

void setup() {
  Serial.begin(115200);
  pinMode(pin, INPUT);
  attachInterrupt(0, analyze, CHANGE);
  results[0] = 0;
}

void analyze() {
  if (index < numSamples) {
    if (index > 0) {
      results[index] = micros() - microseconds;
    }
    index = index + 1;
  }
  microseconds = micros();
}

void loop() {
  if (index >= numSamples) {
   for(byte i=0; i < numSamples; i++) {
     if (results[i] < 3000) {
       Serial.println(results[i]);
     }
   }
   index = 0;
   Serial.println("--");
  }
  delay(500);
}