HC-SR04

// HC-SR04 · ESP32 · Trig=GPIO5, Echo=GPIO18(经分压)
#define TRIG_PIN 5
#define ECHO_PIN 18

void setup() {
  Serial.begin(115200);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  digitalWrite(TRIG_PIN, LOW);
}

float getDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);          // ≥10us 触发脉冲
  digitalWrite(TRIG_PIN, LOW);

  // 30ms 超时:约等于5m的往返时间上限,避免物体太远时死等
  unsigned long duration = pulseIn(ECHO_PIN, HIGH, 30000);
  if (duration == 0) return -1;     // 没测到(超出量程/无反射)
  return duration / 58.0;
}

void loop() {
  float d = getDistanceCM();
  if (d < 0) {
    Serial.println("超出量程或无回波");
  } else {
    Serial.print("距离: ");
    Serial.print(d, 1);
    Serial.println(" cm");
  }
  delay(300);
}

[env:bluepill_f103c8]
platform = ststm32
board = bluepill_f103c8
framework = arduino
upload_protocol = stlink
monitor_speed = 115200
lib_deps =
    adafruit/Adafruit SSD1306@^2.5.13
    adafruit/Adafruit GFX Library@^1.11.11

// HC-SR04 · STM32F103C8T6 · PlatformIO/STM32duino · Trig=PA0, Echo=PA1(经分压)
// 串口通过CP2102接PA9(TX)/PA10(RX) · OLED(SSD1306,I2C,0x3C)可选: SCL=PB6, SDA=PB7
#include <Arduino.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define TRIG_PIN PA0
#define ECHO_PIN PA1
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

HardwareSerial DebugSerial(PA10, PA9);  // RX, TX —— 给 CP2102 看的调试串口
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
  DebugSerial.begin(115200);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  digitalWrite(TRIG_PIN, LOW);

  Wire.begin();
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
}

float getDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  unsigned long duration = pulseIn(ECHO_PIN, HIGH, 30000);
  if (duration == 0) return -1;
  return duration / 58.0;
}

void loop() {
  float d = getDistanceCM();
  if (d < 0) {
    DebugSerial.println("No echo / out of range");
  } else {
    DebugSerial.print("Distance: ");
    DebugSerial.print(d, 1);
    DebugSerial.println(" cm");
  }

  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println("HC-SR04 Distance");

  display.setTextSize(3);
  display.setCursor(10, 24);
  if (d < 0) {
    display.print("--.-");
  } else {
    display.print(d, 1);
  }

  display.setTextSize(1);
  display.setCursor(100, 40);
  display.println("cm");
  display.display();
  delay(300);
}

import RPi.GPIO as GPIO
import time

TRIG = 23   # 物理引脚16
ECHO = 24   # 物理引脚18,经分压电阻接入

GPIO.setmode(GPIO.BCM)
GPIO.setup(TRIG, GPIO.OUT)
GPIO.setup(ECHO, GPIO.IN)
GPIO.output(TRIG, False)
time.sleep(0.5)   # 模块上电稳定

def get_distance_cm():
    GPIO.output(TRIG, True)
    time.sleep(0.00001)   # 10us 触发脉冲
    GPIO.output(TRIG, False)

    timeout = time.time() + 0.03
    while GPIO.input(ECHO) == 0:
        start = time.time()
        if start > timeout:
            return None

    timeout = time.time() + 0.03
    while GPIO.input(ECHO) == 1:
        end = time.time()
        if end > timeout:
            return None

    duration = end - start
    return round((duration * 34300) / 2, 1)   # 声速34300cm/s,除2是往返路程

try:
    while True:
        d = get_distance_cm()
        print(f"距离: {d} cm" if d is not None else "超出量程或无回波")
        time.sleep(0.3)
except KeyboardInterrupt:
    GPIO.cleanup()

// HC-SR04 · Arduino Uno · Trig=D9,Echo=D8 · OLED(SSD1306, I2C, 0x3C)
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define TRIG_PIN 9
#define ECHO_PIN 8
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  digitalWrite(TRIG_PIN, LOW);

  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
}

float getDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  unsigned long duration = pulseIn(ECHO_PIN, HIGH, 30000);
  if (duration == 0) return -1;
  return duration / 58.0;
}

void loop() {
  float d = getDistanceCM();

  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println("HC-SR04 Distance");

  display.setTextSize(3);
  display.setCursor(10, 24);
  if (d < 0) {
    display.print("--.-");
  } else {
    display.print(d, 1);
  }

  display.setTextSize(1);
  display.setCursor(100, 40);
  display.println("cm");

  display.display();
  delay(300);
}