const int pingPin = 7;
const int ledPin = 11;
const int ledPin2 = 10;
int ledLevel = 0;
int ledLevel2 = 255;
int constraint = 0;
void setup()
{
pinMode(ledPin, OUTPUT);
Serial.begin(9600);
}
void loop()
{
long duration, inches, cm;
pinMode(pingPin, OUTPUT);
digitalWrite(pingPin, LOW);
delayMicroseconds(2);
digitalWrite(pingPin, HIGH);
delayMicroseconds(5);
pinMode(pingPin, INPUT);
duration = pulseIn(pingPin, HIGH);
constraint = constrain(duration, 500, 8000);
ledLevel = map(constraint, 500, 8000, 255, 0);
if (ledLevel < 192) {
analogWrite(ledPin, ledLevel);
ledLevel2 = ledLevel2 - 255;
} else if (ledlevel >= 192) {
analogWrite(ledPin, ledLevel);
analogWrite(ledPin2, ledLevel2);
}
Serial.println(duration);
delay(100);
}
这是我的 arduino 代码,当有人开始走向超声波传感器时,它会打开一个 LED,当他们到达 3/4 时,它会打开第二个 LED。当我尝试编译它时,会出现“'ledLevel' 未在此范围内声明”,并突出显示 else if 语句。