Arduino+四位数码管显示电压大小

好的，你可以参考以下代码实现：

int pinA = 2; // 数码管引脚A连接的Arduino引脚
int pinB = 3; // 数码管引脚B连接的Arduino引脚
int pinC = 4; // 数码管引脚C连接的Arduino引脚
int pinD = 5; // 数码管引脚D连接的Arduino引脚
int pinE = 6; // 数码管引脚E连接的Arduino引脚
int pinF = 7; // 数码管引脚F连接的Arduino引脚
int pinG = 8; // 数码管引脚G连接的Arduino引脚
int pinDP = 9; // 数码管引脚DP连接的Arduino引脚

void setup() {
  // 设置引脚为输出模式
  pinMode(pinA, OUTPUT);
  pinMode(pinB, OUTPUT);
  pinMode(pinC, OUTPUT);
  pinMode(pinD, OUTPUT);
  pinMode(pinE, OUTPUT);
  pinMode(pinF, OUTPUT);
  pinMode(pinG, OUTPUT);
  pinMode(pinDP, OUTPUT);
}

void loop() {
  // 读取电压值并转换为字符串
  float voltage = analogRead(A0) * 0.00488; // A0为连接电压传感器的Arduino引脚
  String voltageStr = String(voltage, 2); // 保留两位小数

  // 显示电压值
  display(voltageStr);
  delay(1000);
}

void display(String str) {
  int len = str.length();
  for (int i = 0; i < len; i++) {
    // 显示当前数字
    showDigit(str.charAt(i));
    // 点亮小数点
    if (i == len - 3) {
      digitalWrite(pinDP, HIGH);
    }
    delay(5); // 延时一段时间
    // 关闭数码管
    digitalWrite(pinA, LOW);
    digitalWrite(pinB, LOW);
    digitalWrite(pinC, LOW);
    digitalWrite(pinD, LOW);
    digitalWrite(pinE, LOW);
    digitalWrite(pinF, LOW);
    digitalWrite(pinG, LOW);
    digitalWrite(pinDP, LOW);
  }
}

void showDigit(char c) {
  switch (c) {
    case '0':
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, HIGH);
      digitalWrite(pinF, HIGH);
      digitalWrite(pinG, LOW);
      break;
    case '1':
      digitalWrite(pinA, LOW);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, LOW);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, LOW);
      digitalWrite(pinG, LOW);
      break;
    case '2':
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, LOW);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, HIGH);
      digitalWrite(pinF, LOW);
      digitalWrite(pinG, HIGH);
      break;
    case '3':
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, LOW);
      digitalWrite(pinG, HIGH);
      break;
    case '4':
      digitalWrite(pinA, LOW);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, LOW);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, HIGH);
      digitalWrite(pinG, HIGH);
      break;
    case '5':
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, LOW);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, HIGH);
      digitalWrite(pinG, HIGH);
      break;
    case '6':
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, LOW);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, HIGH);
      digitalWrite(pinF, HIGH);
      digitalWrite(pinG, HIGH);
      break;
    case '7':
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, LOW);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, LOW);
      digitalWrite(pinG, LOW);
      break;
    case '8':
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, HIGH);
      digitalWrite(pinF, HIGH);
      digitalWrite(pinG, HIGH);
      break;
    case '9':
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, HIGH);
      digitalWrite(pinG, HIGH);
      break;
    case '.':
      digitalWrite(pinA, LOW);
      digitalWrite(pinB, LOW);
      digitalWrite(pinC, LOW);
      digitalWrite(pinD, LOW);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, LOW);
      digitalWrite(pinG, HIGH);
      break;
  }
}

注意，以上代码中的数码管引脚连接顺序可能与你实际连接的顺序不同，需要根据实际情况进行修改。另外，电压传感器的输出电压范围可能不同，需要根据具体型号进行调整。