一、利用阿里云服務器實現樹莓派外網訪問（SSH 反向代理）
1. 樹莓派端配置
步驟 1：安裝 SSH 服務（若未安裝）
sudo apt-get install openssh-server步驟 2：創建反向代理連接
-p 22：指定阿里云服務器的 SSH 端口
-qngfN：靜默模式、后臺運行、不分配偽終端
-R：反向代理參數
2222：阿里云服務器用于映射的端口（需自行定義未被占用的端口）
username：阿里云服務器登錄用戶名
步驟 3：設置開機自啟動
將反向代理命令添加到~/.bashrc或創建啟動腳本：
echo "ssh -p 22 -qngfNTR 2222:localhost:22 username@114.55.126.125" >> ~/.bashrc2. 阿里云服務器端配置
步驟 1：檢查端口監聽狀態
ss -ntl | grep 2222若輸出類似LISTEN 0 128 :::2222 :::*，說明端口已成功綁定。
步驟 2：配置防火墻（若使用安全組）
在阿里云控制臺的安全組規則中添加入方向規則，允許 TCP 協議訪問 2222 端口。
3. 外網訪問樹莓派
# 格式: ssh -p [服務器映射端口] [樹莓派用戶名]@[服務器IP]
ssh -p 2222 pi@114.55.126.125二、樹莓派 PWM LED 呼吸燈（含多線程實現）
1. 單線程順序呼吸燈
import RPi.GPIO as GPIO
import time# 設置GPIO模式為BOARD編號
GPIO.setmode(GPIO.BOARD)# 定義LED引腳（可修改為實際連接的引腳）
YELLOW_LED = 11 # 黃燈
GREEN_LED = 16 # 綠燈# 初始化引腳
GPIO.setup(YELLOW_LED, GPIO.OUT)
GPIO.setup(GREEN_LED, GPIO.OUT)# 創建PWM對象（頻率60Hz）
pwm_yellow = GPIO.PWM(YELLOW_LED, 60)
pwm_green = GPIO.PWM(GREEN_LED, 60)# 啟動PWM（初始占空比0）
pwm_yellow.start(0)
pwm_green.start(0)try:# 循環3次呼吸效果for _ in range(3):# 黃燈呼吸for dc in range(0, 101, 5):pwm_yellow.ChangeDutyCycle(dc)time.sleep(0.05)for dc in range(100, -1, -5):pwm_yellow.ChangeDutyCycle(dc)time.sleep(0.05)# 綠燈呼吸for dc in range(0, 101, 5):pwm_green.ChangeDutyCycle(dc)time.sleep(0.05)for dc in range(100, -1, -5):pwm_green.ChangeDutyCycle(dc)time.sleep(0.05)finally:# 停止PWM并清理資源pwm_yellow.stop()pwm_green.stop()GPIO.cleanup()2. 多線程同時呼吸燈實現
import RPi.GPIO as GPIO
import time
import threading# 設置GPIO模式
GPIO.setmode(GPIO.BOARD)# 定義LED引腳
YELLOW_LED = 11
GREEN_LED = 16# 初始化引腳
GPIO.setup(YELLOW_LED, GPIO.OUT)
GPIO.setup(GREEN_LED, GPIO.OUT)# 創建PWM對象
pwm_yellow = GPIO.PWM(YELLOW_LED, 60)
pwm_green = GPIO.PWM(GREEN_LED, 60)# 啟動PWM
pwm_yellow.start(0)
pwm_green.start(0)def yellow_breath():"""黃燈呼吸函數"""for _ in range(3):for dc in range(0, 101, 5):pwm_yellow.ChangeDutyCycle(dc)time.sleep(0.05)for dc in range(100, -1, -5):pwm_yellow.ChangeDutyCycle(dc)time.sleep(0.05)def green_breath():"""綠燈呼吸函數"""for _ in range(3):for dc in range(0, 101, 5):pwm_green.ChangeDutyCycle(dc)time.sleep(0.05)for dc in range(100, -1, -5):pwm_green.ChangeDutyCycle(dc)time.sleep(0.05)try:# 創建并啟動線程t1 = threading.Thread(target=yellow_breath)t2 = threading.Thread(target=green_breath)t1.start()t2.start()# 等待線程結束t1.join()t2.join()finally:# 清理資源pwm_yellow.stop()pwm_green.stop()GPIO.cleanup()三、樹莓派超聲波測距程序
1. 硬件連接
超聲波模塊 Trig 引腳 → 樹莓派 GPIO23（BCM 編號）
超聲波模塊 Echo 引腳 → 樹莓派 GPIO24（BCM 編號）
模塊 VCC → 樹莓派 5V
模塊 GND → 樹莓派 GND
2. 完整代碼
import RPi.GPIO as GPIO
import time# 設置GPIO模式為BCM
GPIO.setmode(GPIO.BCM)# 定義引腳
TRIG_PIN = 23
ECHO_PIN = 24# 初始化引腳
GPIO.setup(TRIG_PIN, GPIO.OUT)
GPIO.setup(ECHO_PIN, GPIO.IN)def measure_distance():"""測量距離函數"""# 發送觸發信號GPIO.output(TRIG_PIN, True)time.sleep(0.00001) # 10微秒GPIO.output(TRIG_PIN, False)# 記錄發送和接收時間start_time = time.time()stop_time = time.time()# 等待Echo變為高電平（發送超聲波）while GPIO.input(ECHO_PIN) == 0:start_time = time.time()# 等待Echo變為低電平（接收超聲波）while GPIO.input(ECHO_PIN) == 1:stop_time = time.time()# 計算距離（聲速343m/s，轉換為cm）time_elapsed = stop_time - start_timedistance = (time_elapsed * 34300) / 2return distancetry:print("超聲波測距程序啟動，按Ctrl+C停止")while True:dist = measure_distance()print(f"距離: {dist:.2f} cm")time.sleep(1) # 每秒測量一次except KeyboardInterrupt:print("程序停止")
finally:GPIO.cleanup()四、Linux 驅動程序控制 PWM（含編譯與測試）
1. 準備編譯環境
# 安裝內核頭文件（樹莓派專用）
sudo apt-get install raspberrypi-kernel-headers2. 驅動程序代碼
pwmled.h 文件
#define PWMLED_MAX_BRIGHTNESS 1000typedef enum {PWMLED_CMD_SET_BRIGHTNESS = 0x1,PWMLED_CMD_GET_BRIGHTNESS,
} pwmled_cmd_t;pwmled.c 文件
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/pwm.h>
#include "pwmled.h"MODULE_LICENSE("Dual MIT/GPL");
MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("PWM LED Driver");#define PWM_PERIOD_NS 1000000 // 1ms周期（1000000納秒）static struct {struct pwm_device *pwm;unsigned int brightness;
} pwmled;// IOCTL處理函數
long pwmled_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) {switch (cmd) {case PWMLED_CMD_SET_BRIGHTNESS:// 限制亮度范圍0~1000pwmled.brightness = arg > PWMLED_MAX_BRIGHTNESS ? PWMLED_MAX_BRIGHTNESS : arg;// 計算占空比（亮度*1000納秒）int duty_ns = pwmled.brightness * 1000;// 配置PWMpwm_config(pwmled.pwm, duty_ns, PWM_PERIOD_NS);// 啟用或禁用PWMif (pwmled.brightness > 0) {pwm_enable(pwmled.pwm);} else {pwm_disable(pwmled.pwm);}break;case PWMLED_CMD_GET_BRIGHTNESS:return pwmled.brightness;default:return -EINVAL;}return 0;
}// 文件操作結構體
static struct file_operations fops = {.owner = THIS_MODULE,.unlocked_ioctl = pwmled_ioctl,
};// 雜項設備結構體
static struct miscdevice pwmled_misc = {.minor = MISC_DYNAMIC_MINOR,.name = "pwmled",.fops = &fops,
};// 模塊初始化函數
int __init pwmled_init(void) {int ret;// 請求PWM通道0（根據實際硬件修改通道號）pwmled.pwm = pwm_request(0, "pwmled");if (IS_ERR(pwmled.pwm)) {ret = PTR_ERR(pwmled.pwm);printk(KERN_ERR "Failed to request PWM channel\n");return ret;}// 初始化亮度為0pwmled.brightness = 0;// 注冊雜項設備ret = misc_register(&pwmled_misc);if (ret < 0) {printk(KERN_ERR "Failed to register misc device\n");pwm_free(pwmled.pwm);return ret;}printk(KERN_INFO "PWM LED driver initialized\n");return 0;
}// 模塊退出函數
void __exit pwmled_exit(void) {// 禁用PWMpwm_disable(pwmled.pwm);// 釋放PWM資源pwm_free(pwmled.pwm);// 注銷雜項設備misc_deregister(&pwmled_misc);printk(KERN_INFO "PWM LED driver unloaded\n");
}module_init(pwmled_init);
module_exit(pwmled_exit);3. 編譯驅動（Makefile）
obj-m += pwmled.oall:make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
clean:make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean4. 加載驅動與測試
步驟 1：編譯并加載驅動
# 編譯驅動
make
# 加載驅動
sudo insmod pwmled.ko步驟 2：查看設備節點
ls /dev/pwmled步驟 3：編寫測試程序
import os
import fcntl# 定義IOCTL命令
PWMLED_CMD_SET_BRIGHTNESS = 0x1
PWMLED_CMD_GET_BRIGHTNESS = 0x2# 打開設備文件
fd = os.open("/dev/pwmled", os.O_RDWR)
if fd < 0:print("Failed to open /dev/pwmled")exit(1)try:# 設置亮度（0~1000）brightness = 500print(f"設置亮度為: {brightness}")fcntl.ioctl(fd, PWMLED_CMD_SET_BRIGHTNESS, brightness)# 等待5秒time.sleep(5)# 獲取當前亮度current_brightness = fcntl.ioctl(fd, PWMLED_CMD_GET_BRIGHTNESS)print(f"當前亮度: {current_brightness}")finally:# 關閉設備文件os.close(fd)步驟 4：卸載驅動
sudo rmmod pwmled
