Arduino硬件中断可靠性问题

Question

这似乎是一个愚蠢的问题，也许它的描述不是我能设计的最好的。

我正在制作一个速度传感器，它使用两个红外光束来计算速度，这是根据断开两个光束所需的时间来计算的。

我有两种测试方法。

1. 我的手（5-10米/秒）
2. 高速加农炮（30-60米/秒）。

我已经排除了使用示波器来自IR光束的信号出现问题，当代码失败/工作时，数据在示波器上是相同的。

我的问题是我的代码在我用手时起作用，但仍然不规则地失败，而它经常在高速下失败。两种情况下的所有条件都相同。可能是什么问题？

#include <SPI.h>
#include <SD.h>
#include <LiquidCrystal.h>

const int rs = 9, en = 8, d4 = 7, d5 = 6, d6 = 5, d7 = 4;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

File root;
int fileNo = 0;
String currentFileName;
const int CS = 10;
const byte interruptPinStart = 2;
const byte interruptPinFinish = 3;

volatile unsigned long int startTimeMillis = 0;
volatile unsigned long int stopTimeMillis = 0;
volatile unsigned long int startTimeMicros = 0;
volatile unsigned long int stopTimeMicros = 0;
volatile unsigned long int microsDifference = 0;
volatile unsigned long int millisDifference = 0;

int launchNo = 0;
float currentVelocity = 0;
volatile boolean started = false;
String inputString = "";       
boolean stringComplete = false;  
const int txLed1 = 14;
const int statusLed1 = 15;
const int statusLed2 = 16;
volatile boolean triggerDone = false;
float velocity = 0;
String temp;
unsigned long int lockout = 0;
boolean lockedOut = false;
boolean fileFail = false;
int testNo = 0;

void setup() {
  inputString.reserve(200);
  pinMode(statusLed1, OUTPUT);
  pinMode(statusLed2, OUTPUT);
  pinMode(txLed1, OUTPUT);
  Serial.begin(9600);
  while (!Serial) {
    ; 
  }
  lcd.begin(16, 2);
  pinMode(interruptPinStart, INPUT);
  attachInterrupt(digitalPinToInterrupt(interruptPinStart), startTrigger, RISING);
  pinMode(interruptPinFinish, INPUT);
  attachInterrupt(digitalPinToInterrupt(interruptPinFinish), stopTrigger, RISING);
  Serial.print("Initializing SD card...");
  if (!SD.begin(CS)) {
    Serial.println("initialization failed!");
    return;
  }
  Serial.println("initialization done.");
  root = SD.open("/");
  newDirectory(root);
  Serial.println("done!");
  lcd.clear();
  lcd.print(currentFileName);
  tone(txLed1, 38000);
}

void loop() {
  int millsDiff = millis() - stopTimeMillis;
  if (triggerDone) {
    lockedOut = true;
    Serial.print("Micros Diffrence: ");
    Serial.println(microsDifference);
    Serial.print("Millis Difference: ");
    Serial.println(millisDifference);
    float millDiff = (float) millisDifference;
    float microDiff = (float) microsDifference;
    if (microDiff > 0) {
      velocity = (float) 0.09 / (microDiff/1000000);
      testNo++;
      temp = String(launchNo) + "%" + String(microsDifference) + "%" + String(velocity);
      if (velocity > 10.0) {
        root = SD.open(currentFileName, FILE_WRITE);
        if (root) {
          root.println(temp);
          root.close();
          Serial.println(temp);
          launchNo++;
        } else {
          Serial.println("error opening file, " + currentFileName);
          fileFail = true;
        }
      }
      if (fileFail) {
        lcd.clear();
        lcd.print("File Error");
        lcd.setCursor(0, 1);
        lcd.print("Vel " + String(launchNo) + ": " + String(velocity) + " m/s");
        fileFail = false;
      } else {
        lcd.clear();
        lcd.print("Test Number: " + String(testNo));
        lcd.setCursor(0, 1);
        lcd.print("Vel " + String(launchNo) + ": " + String(velocity) + " m/s");
      }
    } 
    triggerDone = false;
    Serial.println("Test Number: " + String(testNo));
  }
  if (digitalRead(interruptPinStart) == LOW) {
    digitalWrite(statusLed1, HIGH);
  } else {
    digitalWrite(statusLed1, LOW);
  }
  if (digitalRead(interruptPinFinish) == LOW) {
    digitalWrite(statusLed2, HIGH);
  } else {
    digitalWrite(statusLed2, LOW);
  }
}

void startTrigger() {
  startTimeMicros = micros();
  startTimeMillis = millis();
  volatile int diff1 = startTimeMicros - startTimeMillis;
  volatile int diff2 = startTimeMillis - stopTimeMillis;
  if (diff2 > 200) {
    if (started == false || diff1 > 1000) {
      started = true;
      triggerDone = false;
    }
  }
}

void stopTrigger() {
  stopTimeMicros = micros();
  stopTimeMillis = millis();
  microsDifference = stopTimeMicros - startTimeMicros;
  millisDifference = stopTimeMillis - startTimeMillis;
  if ((millisDifference > 0  && millisDifference < 800) && started) {
    microsDifference = stopTimeMicros - startTimeMicros;
    millisDifference = stopTimeMillis - startTimeMillis;
    started = false;
    triggerDone = true;
  }
}