我正试图用我的Arduino和我的服务器创建一个domotica设置。在使用射频发射器之前，我试图从我的php网页控制LED（设置它们打开/关闭）。
这一切都很完美，除了LED1在我加载/刷新网页时打开。我的网页包含以下代码（我改编自https://www.lassiemarlowe.com/tutorials/power-led-bulbs-arduino-php-part-2/)：
<html>
<head>
<title>Arduino Domotica Control Panel</title>
这里有一些css代码。。。
<?php
switch($_POST)
{
case isset($_POST['submitOn']):
$fp = fopen("/dev/ttyUSB1", "w");
fwrite($fp, 1);
fclose($fp);
break;
case isset($_POST['submitOff']):
$fp = fopen("/dev/ttyUSB1", "w");
fwrite($fp, 2);
fclose($fp);
break;
case isset($_POST['submitOn1']):
$fp = fopen("/dev/ttyUSB1", "w");
fwrite($fp, 3);
fclose($fp);
break;
case isset($_POST['submitOff1']):
$fp = fopen("/dev/ttyUSB1", "w");
fwrite($fp, 4);
fclose($fp);
break;
case isset($_POST['submitOn2']):
$fp = fopen("/dev/ttyUSB1", "w");
fwrite($fp, 5);
fclose($fp);
break;
case isset($_POST['submitOff2']):
$fp = fopen("/dev/ttyUSB1", "w");
fwrite($fp, 6);
fclose($fp);
break;
case isset($_POST['allon']):
$fp = fopen("/dev/ttyUSB1", "w");
fwrite($fp, 7);
fclose($fp);
break;
case isset($_POST['alloff']):
$fp = fopen("/dev/ttyUSB1", "w");
fwrite($fp, 8);
fclose($fp);
break;
}
?>
</head>
<body>
<h1>Control Panel</h1>
<form class="control-panel-frm" method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
<input type='submit' class="s3d turnOn" name='submitOn' value='LED 1 on'>
<input type='submit' class="s3d switchoff" name='submitOff' value='LED 1 off'>
<br><br>
<input type='submit' class="s3d turnOn" name='submitOn1' value='LED 2 on'>
<input type='submit' class="s3d switchoff" name='submitOff1' value='LED 2 off'>
<br><br>
<input type='submit' class="s3d turnOn" name='submitOn2' value='LED 3 on'>
<input type='submit' class="s3d switchoff" name='submitOff2' value='LED 3 off'>
<br><br>
<input type='submit' class="s3d turnOn" name='allon' value='All LEDs on'>
<input type='submit' class="s3d switchoff" name='alloff' value='All LEDs off'>
</form>
如前所述，问题是LED1（对应于php post"submitOn"）在我加载/刷新网页时打开。检查串行监视器时，Arduino会收到一个"1"。
为了防止我的网页在加载时向Arduino发送任何内容，我应该更改什么
我想您对开关的理解是错误的。Switch将大括号()中的值与大小写给定的值进行比较。请参阅开关的手册页面，以获得有关此方面的更多说明。
除此之外，您还可以将数据从html表单传输到PHP应用程序。您将LED 1 on作为表单元素submitOn的值发送。
试试这个：
<?php
$actions = [
'submitOn' => 1,
'submitOff' => 2,
//...
];
if(!empty($_POST['action']) && array_key_exists($_POST['action'], $actions)){
$fp = fopen("/dev/ttyUSB1", "w");
fwrite($fp, $actions[$_POST['action']]);
fclose($fp);
}
?>
<form class="control-panel-frm" method="post" action="">
<input type="submit" class="s3d turnOn" name="action" value="submitOn">
<input type="submit" class="s3d switchoff" name="action" value="submitOff">
</form>
请注意，表单的空action将表单数据发送到当前页面。有关多个提交按钮的使用，请参阅一个表单中的两个提交按钮。