(五)在MCU上写Python,这些坑我帮你踩过了——MicroPython语言实战指南

# ❌ 错误：b和a指向同一个lista = [1, 2, 3]b = ab.append(4)print(a)  # [1, 2, 3, 4] — a也被改了！# ✅ 正确：显式复制a = [1, 2, 3]b = list(a)  # 或 a.copy()b.append(4)print(a)  # [1, 2, 3] — 不受影响

from micropython import const# const()让编译器直接替换常量值# 减少字节码体积和全局字典开销_MIN_PIXELS = const(80)_MAX_BLOBS = const(20)_CONFIDENCE = const(0.75)

# ✅ 好的做法：初始化阶段创建所有对象import sensor, image, timefrom micropython import const# 初始化（只执行一次）sensor.reset()sensor.set_pixformat(sensor.RGB565)sensor.set_framesize(sensor.QVGA)sensor.skip_frames(time=2000)# 预分配阈值（元组，不可变，省内存）RED_THRESHOLD = (30, 100, 15, 127, 15, 127)BLUE_THRESHOLD = (0, 50, -30, 30, -50, -20)# 预分配结构稳定的字典config = {"min_area": 200, "max_blobs": 10}clock = time.clock()# 帧循环（反复执行）while True:    clock.tick()    img = sensor.snapshot()  # 复用帧缓冲    blobs = img.find_blobs([RED_THRESHOLD], pixels_threshold=config["min_area"])    for blob in blobs[:config["max_blobs"]]:        img.draw_rectangle(blob.rect())    print(f"FPS: {clock.fps():.1f}")

# ❌ 错误1：每帧都创建新字符串while True:    img = sensor.snapshot()    result = f"Found {len(blobs)} blobs at {time.ticks_ms()}"  # 每帧新字符串！# ✅ 正确：预先格式化while True:    img = sensor.snapshot()    print(len(blobs), time.ticks_ms())  # 分开打印，不拼接# ❌ 错误2：持有snapshot()引用img1 = sensor.snapshot()img2 = sensor.snapshot()diff = img1.difference(img2)  # img1已被覆盖！结果错误# ✅ 正确：复制需要保留的帧img1 = sensor.snapshot().copy()img2 = sensor.snapshot()diff = img1.difference(img2)  # 正确# ❌ 错误3：循环中不断appendresults = []while True:    img = sensor.snapshot()    blobs = img.find_blobs([threshold])    results.extend(blobs)  # 无限增长！内存泄漏# ✅ 正确：清空或限制大小while True:    img = sensor.snapshot()    blobs = img.find_blobs([threshold])    # 只处理当前帧结果，不累积

"""零件分拣系统 - 基于颜色识别ESP-VISION MicroPython"""import sensor, image, timefrom micropython import const# 常量定义RED_THRESHOLD = const((30, 100, 15, 127, 15, 127))BLUE_THRESHOLD = const((0, 50, -30, 30, -50, -20))GREEN_THRESHOLD = const((0, 50, -50, -10, 0, 50))MIN_AREA = const(500)MAX_BLOBS = const(10)# 初始化摄像头sensor.reset()sensor.set_pixformat(sensor.RGB565)sensor.set_framesize(sensor.QVGA)sensor.skip_frames(time=2000)# 颜色映射COLOR_MAP = {    "red": RED_THRESHOLD,    "blue": BLUE_THRESHOLD,    "green": GREEN_THRESHOLD,}clock = time.clock()def classify_parts():    """分类并计数零件"""    img = sensor.snapshot()    results = {}    for color_name, threshold in COLOR_MAP.items():        blobs = img.find_blobs([threshold], pixels_threshold=MIN_AREA)        count = min(len(blobs), MAX_BLOBS)        results[color_name] = count        # 绘制检测框        for blob in blobs[:MAX_BLOBS]:            img.draw_rectangle(blob.rect(), color=(255, 0, 0))            img.draw_cross(blob.cx(), blob.cy())    return results# 主循环while True:    clock.tick()    results = classify_parts()    print(f"FPS: {clock.fps():.1f} | Red: {results['red']} | "          f"Blue: {results['blue']} | Green: {results['green']}")