第十课 使用Python控制小车
上一节课程我们介绍了怎么连接,以及简单的演示了下怎么控制小车。这节我们将详细介绍python代码,和为什么这样去做。下面是将要用到的代码,首先是robot.py
文件:
#!/usr/bin/python
#coding: utf8
import RPIO as GPIO
import time
import sys
import threading
import tornado.ioloop
import tornado.web
import tornado.httpserver
import tornado.options
import json
tornado.options.define("port",default=8000,type=int)
IN1 = 11
IN2 = 12
IN3 = 16
IN4 = 18
stop_status = 0
last_key = ""
last_request_time = 0
def init():
GPIO.setmode(GPIO.BOARD)
GPIO.setup(IN1,GPIO.OUT)
GPIO.setup(IN2,GPIO.OUT)
GPIO.setup(IN3,GPIO.OUT)
GPIO.setup(IN4,GPIO.OUT)
# 前进
def forward():
global stop_status
GPIO.output(IN1,GPIO.HIGH)
GPIO.output(IN2,GPIO.LOW)
GPIO.output(IN3,GPIO.HIGH)
GPIO.output(IN4,GPIO.LOW)
# print "forward"
# time.sleep(0.1)
# 后退
def reverse():
global stop_status
GPIO.output(IN1,GPIO.LOW)
GPIO.output(IN2,GPIO.HIGH)
GPIO.output(IN3,GPIO.LOW)
GPIO.output(IN4,GPIO.HIGH)
# 左转弯
def left():
global stop_status
GPIO.output(IN1,GPIO.LOW)
GPIO.output(IN2,GPIO.HIGH)
GPIO.output(IN3,GPIO.HIGH)
GPIO.output(IN4,GPIO.LOW)
# 右转弯
def right():
global stop_status
GPIO.output(IN1,GPIO.HIGH)
GPIO.output(IN2,GPIO.LOW)
GPIO.output(IN3,GPIO.LOW)
GPIO.output(IN4,GPIO.HIGH)
#停止
def stop_car():
GPIO.output(IN1,False)
GPIO.output(IN2,False)
GPIO.output(IN3,False)
GPIO.output(IN4,False)
global stop_status
stop_status = 1
#关闭GPIO接口
def close_car():
global stop_status
stop_status = 1
GPIO.cleanup()
class IndexHandler(tornado.web.RequestHandler):
def set_default_headers(self):
self.set_header('Access-Control-Allow-Origin', '*')
self.set_header('Access-Control-Allow-Methods', 'POST, GET, OPTIONS')
self.set_header('Access-Control-Allow-Headers', '*')
def get(self):
self.render("index.html")
def post(self):
global stop_status
global last_key
global last_request_time
old_request_time = last_request_time
init()
sleep_time = 0.1
try:
arg = self.get_argument('k')
new_request_time = self.get_argument('time')
print 'get last time',new_request_time
except Exception, e:
arg = json.loads(self.request.body)['k']
new_request_time = json.loads(self.request.body)['time']
print 'json last time', new_request_time
print "==new time ==", new_request_time
print "==old time ==", old_request_time
if(arg=='w' and last_key!='w' and new_request_time >= old_request_time):
print "forward"
stop_status = 0
autoThread = threading.Thread(target = forward)
autoThread.start()
last_key = 'w'
elif(arg=='s' and last_key!='s' and new_request_time >= old_request_time):
print "reverse"
stop_status = 0
autoThread = threading.Thread(target = reverse)
autoThread.start()
last_key = 's'
elif(arg=='a' and last_key!='a' and new_request_time >= old_request_time):
print "left"
stop_status = 0
autoThread = threading.Thread(target = left)
autoThread.start()
last_key = 'a'
elif(arg=='d' and last_key!='d' and new_request_time >= old_request_time):
print "right"
stop_status = 0
autoThread = threading.Thread(target = right)
autoThread.start()
last_key = 'd'
elif(arg=='stop' and new_request_time >= old_request_time):
print "stop"
last_key = "stop"
time.sleep(0.3)
stop_car()
else:
print "error"
last_request_time = new_request_time
self.write(arg)
def options(self):
pass
if __name__ == '__main__':
tornado.options.parse_command_line()
app = tornado.web.Application(handlers=[(r"/",IndexHandler)])
http_server = tornado.httpserver.HTTPServer(app)
http_server.listen(tornado.options.options.port)
tornado.ioloop.IOLoop.instance().start()
然后是index.html
文件:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>WIFI小车客户端</title>
<script src="http://libs.baidu.com/jquery/1.9.0/jquery.js"></script>
</head>
<body>
<script type="text/javascript">
function go(k){
var requestTime= new Date().getTime();
$.post('/',{k:k,time:requestTime},function(){},"json");
}
$(function(){
var i = null;
window.document.onkeydown = keyDown;
function keyDown(env){
env = (env) ? env : window.event;
if(env.keyCode=='87'){
go('w');
}
if(env.keyCode=='83'){
go('s');
}
if(env.keyCode=='65'){
go('a');
}
if(env.keyCode=='68'){
go('d');
}
};
window.document.onkeyup = keyUp;
function keyUp(env){
env = (env) ? env : window.event;
if(env.keyCode=='87'){
go('stop');
}
if(env.keyCode=='83'){
go('stop');
}
if(env.keyCode=='65'){
go('stop');
}
if(env.keyCode=='68'){
go('stop');
}
}
$('.before').mousedown(function(){
i = setInterval(function(){
go('w');
},100);
});
$('.left').mousedown(function(){
i = setInterval(function(){
go('a');
},100);
});
$('.right').mousedown(function(){
i = setInterval(function(){
go('d');
},100);
});
$('.cabk').mousedown(function(){
i = setInterval(function(){
go('s');
},100);
});
$('#main span').mouseup(function(){
clearInterval(i);
go('stop');
});
});
</script>
<style type="text/css">
#main{width: 150px;height: 150px;background: #ccc;}
#main span{width: 50px;height: 50px;float: left;z-index: 999;}
#main span.on2{background: #ff00ff;}
</style>
<div id="main">
<span></span>
<span class="on2 before"></span>
<span></span>
<span class="on2 left"></span>
<span></span>
<span class="on2 right"></span>
<span></span>
<span class="on2 cabk"></span>
<span></span>
</div>
</body>
</html>
代码会持续更新在Github上地址,有兴趣的可以watch
下,这您将第一时间收到更新通知。