11. 视频小车

此程序为您提供 PiCar-X 的第一视角体验！通过键盘上的 WSAD 键控制方向， 使用 O 和 P 键调整速度。

运行代码

cd ~/picar-x/example
sudo python3 11.video_car.py

代码运行后，您可以看到 PiCar-X 拍摄的画面，并通过以下按键进行控制：

• O: 加速

• P: 减速

• W: 前进

• S: 后退

• A: 左转

• D: 右转

• F: 停止

• T: 拍照

• Ctrl+C: 退出

查看画面

代码运行后，终端将显示以下提示：

No desktop !
* Serving Flask app "vilib.vilib" (lazy loading)
* Environment: production
WARNING: Do not use the development server in a production environment.
Use a production WSGI server instead.
* Debug mode: off
* Running on http://0.0.0.0:9000/ (Press CTRL+C to quit)

然后您可以在浏览器中输入 http://<你的IP>:9000/mjpg 查看视频画面，例如： https://192.168.18.113:9000/mjpg

代码

#!/usr/bin/env python3

from robot_hat.utils import reset_mcu
from picarx import Picarx
from vilib import Vilib
from time import sleep, time, strftime, localtime
import readchar

import os
user = os.getlogin()
user_home = os.path.expanduser(f'~{user}')

reset_mcu()
sleep(0.2)

manual = '''
按下键盘按键以调用功能（不区分大小写）：

    O: 加速
    P: 减速
    W: 前进
    S: 后退
    A: 左转
    D: 右转
    F: 停止
    T: 拍照

    Ctrl+C: 退出
'''


px = Picarx()

def take_photo():
    _time = strftime('%Y-%m-%d-%H-%M-%S',localtime(time()))
    name = 'photo_%s'%_time
    path = f"{user_home}/Pictures/picar-x/"
    Vilib.take_photo(name, path)
    print('\nphoto save as %s%s.jpg'%(path,name))


def move(operate:str, speed):

    if operate == 'stop':
        px.stop()
    else:
        if operate == 'forward':
            px.set_dir_servo_angle(0)
            px.forward(speed)
        elif operate == 'backward':
            px.set_dir_servo_angle(0)
            px.backward(speed)
        elif operate == 'turn left':
            px.set_dir_servo_angle(-30)
            px.forward(speed)
        elif operate == 'turn right':
            px.set_dir_servo_angle(30)
            px.forward(speed)



def main():
    speed = 0
    status = 'stop'

    Vilib.camera_start(vflip=False,hflip=False)
    Vilib.display(local=True,web=True)
    sleep(2)  # 等待启动
    print(manual)

    while True:
        print("\rstatus: %s , speed: %s    "%(status, speed), end='', flush=True)
        # 读取按键
        key = readchar.readkey().lower()
        # 操作处理
        if key in ('wsadfop'):
            # 油门
            if key == 'o':
                if speed <=90:
                    speed += 10
            elif key == 'p':
                if speed >=10:
                    speed -= 10
                if speed == 0:
                    status = 'stop'
            # 方向控制
            elif key in ('wsad'):
                if speed == 0:
                    speed = 10
                if key == 'w':
                    # 倒车时限速，避免瞬间电流过大
                    if status != 'forward' and speed > 60:
                        speed = 60
                    status = 'forward'
                elif key == 'a':
                    status = 'turn left'
                elif key == 's':
                    if status != 'backward' and speed > 60: # 倒车时限速
                        speed = 60
                    status = 'backward'
                elif key == 'd':
                    status = 'turn right'
            # 停止
            elif key == 'f':
                status = 'stop'
            # 移动
            move(status, speed)
        # 拍照
        elif key == 't':
            take_photo()
        # 退出
        elif key == readchar.key.CTRL_C:
            print('\nquit ...')
            px.stop()
            Vilib.camera_close()
            break

        sleep(0.1)


if __name__ == "__main__":
    try:
        main()
    except Exception as e:
        print("error:%s"%e)
    finally:
        px.stop()
        Vilib.camera_close()