Voy a dedicar este post a explicar, un poco más en detalle, la comunicación entre Arduino y el servidor web a través del puerto serie (en este caso, USB), utilizando una clase de PHP creada por Rémy Sanchez.
El principio es el mismo que utiliza la aplicación de Arduino para comunicarse con la placa a través del "Serial Monitor". La cuestión aquí es, como enviar y recibir esos datos desde nuestro servidor web.
Yo he utilizado una clase de PHP, ya preparada, para comunicarme con el puerto serie del ordenador. Esta clase funciona perfectamente sobre un servidor en Linux. Según su autor, también es compatible con Windows, pero solo para enviar mensajes.
No hace falta más que este pequeño fragmento de código, para empezar a jugar:
<?php // incluímos la clase necesaria para la comunicación require("php_serial.class.php"); $serial = new phpSerial; // indicamos que puerto serie queremos usar $serial->deviceSet("/dev/ttyACM0"); // ahora la velocidad de transmisión de Arduino $serial->confBaudRate(115200); $serial->deviceOpen(); // aquí el String que queremos enviar $serial->sendMessage("light"); sleep (1); $serial->deviceClose(); ?>
Yo de momento solo lo he utilizado para enviar. Pero en caso de querer recibir habría que utilizar la función readPort(). Como parámetro podemos enviarle el número de caracteres que debe leer, nos devuelve un String.
<?php // guardamos en $read la cadena de // caracteres que hemos recibido de Arduino $read = $serial->readPort(); ?>
A continuación os dejo la clase necesaria para poder usar estas funciones. Unicamente tendréis que guardarla en un archivo a parte, respetando el nombre que os indico como título del código, para que os funcione con el ejemplo que he puesto arriba.
php_serial.class.php
<?php
define ("SERIAL_DEVICE_NOTSET", 0);
define ("SERIAL_DEVICE_SET", 1);
define ("SERIAL_DEVICE_OPENED", 2);
/**
* Serial port control class
*
* THIS PROGRAM COMES WITH ABSOLUTELY NO WARANTIES !
* USE IT AT YOUR OWN RISKS !
*
* Changes added by Rizwan Kassim <rizwank@uwink.com> for OSX functionality
* default serial device for osx devices is /dev/tty.serial for machines with a built in serial device
*
* @author RÈmy Sanchez <thenux@gmail.com>
* @thanks AurÈlien Derouineau for finding how to open serial ports with windows
* @thanks Alec Avedisyan for help and testing with reading
* @copyright under GPL 2 licence
*
* do not change this code unless you know what you are getting into. Leaving it as you have received it should work fine!
*/
class phpSerial
{
var $_device = null;
var $_windevice = null;
var $_dHandle = null;
var $_dState = SERIAL_DEVICE_NOTSET;
var $_buffer = "";
var $_os = "";
/**
* This var says if buffer should be flushed by sendMessage (true) or manualy (false)
*
* @var bool
*/
var $autoflush = true;
/**
* Constructor. Perform some checks about the OS and setserial
*
* @return phpSerial
*/
function phpSerial ()
{
setlocale(LC_ALL, "en_US");
$sysname = php_uname();
if (substr($sysname, 0, 5) === "Linux")
{
$this->_os = "linux";
if($this->_exec("stty --version") === 0)
{
register_shutdown_function(array($this, "deviceClose"));
}
else
{
trigger_error("No stty availible, unable to run.", E_USER_ERROR);
}
}
elseif (substr($sysname, 0, 6) === "Darwin")
{
$this->_os = "osx";
// We know stty is available in Darwin.
// stty returns 1 when run from php, because "stty: stdin isn't a
// terminal"
// skip this check
// if($this->_exec("stty") === 0)
// {
register_shutdown_function(array($this, "deviceClose"));
// }
// else
// {
// trigger_error("No stty availible, unable to run.", E_USER_ERROR);
// }
}
elseif(substr($sysname, 0, 7) === "Windows")
{
$this->_os = "windows";
register_shutdown_function(array($this, "deviceClose"));
}
else
{
trigger_error("Host OS is neither osx, linux nor windows, unable tu run.", E_USER_ERROR);
exit();
}
}
//
// OPEN/CLOSE DEVICE SECTION -- {START}
//
/**
* Device set function : used to set the device name/address.
* -> linux : use the device address, like /dev/ttyS0
* -> osx : use the device address, like /dev/tty.serial
* -> windows : use the COMxx device name, like COM1 (can also be used
* with linux)
*
* @param string $device the name of the device to be used
* @return bool
*/
function deviceSet ($device)
{
if ($this->_dState !== SERIAL_DEVICE_OPENED)
{
if ($this->_os === "linux")
{
if (preg_match("@^COM(\d+):?$@i", $device, $matches))
{
$device = "/dev/ttyS" . ($matches[1] - 1);
}
if ($this->_exec("stty -F " . $device) === 0)
{
$this->_device = $device;
$this->_dState = SERIAL_DEVICE_SET;
return true;
}
}
elseif ($this->_os === "osx")
{
if ($this->_exec("stty -f " . $device) === 0)
{
$this->_device = $device;
$this->_dState = SERIAL_DEVICE_SET;
return true;
}
}
elseif ($this->_os === "windows")
{
if (preg_match("@^COM(\d+):?$@i", $device, $matches) and $this->_exec(exec("mode " . $device)) === 0)
{
$this->_windevice = "COM" . $matches[1];
$this->_device = "\\.\com" . $matches[1];
$this->_dState = SERIAL_DEVICE_SET;
return true;
}
}
trigger_error("Specified serial port is not valid", E_USER_WARNING);
return false;
}
else
{
trigger_error("You must close your device before to set an other one", E_USER_WARNING);
return false;
}
}
/**
* Opens the device for reading and/or writing.
*
* @param string $mode Opening mode : same parameter as fopen()
* @return bool
*/
function deviceOpen ($mode = "r+b")
{
if ($this->_dState === SERIAL_DEVICE_OPENED)
{
trigger_error("The device is already opened", E_USER_NOTICE);
return true;
}
if ($this->_dState === SERIAL_DEVICE_NOTSET)
{
trigger_error("The device must be set before to be open", E_USER_WARNING);
return false;
}
if (!preg_match("@^[raw]\+?b?$@", $mode))
{
trigger_error("Invalid opening mode : ".$mode.". Use fopen() modes.", E_USER_WARNING);
return false;
}
$this->_dHandle = @fopen($this->_device, $mode);
if ($this->_dHandle !== false)
{
stream_set_blocking($this->_dHandle, 0);
$this->_dState = SERIAL_DEVICE_OPENED;
return true;
}
$this->_dHandle = null;
trigger_error("Unable to open the device", E_USER_WARNING);
return false;
}
/**
* Closes the device
*
* @return bool
*/
function deviceClose ()
{
if ($this->_dState !== SERIAL_DEVICE_OPENED)
{
return true;
}
if (fclose($this->_dHandle))
{
$this->_dHandle = null;
$this->_dState = SERIAL_DEVICE_SET;
return true;
}
trigger_error("Unable to close the device", E_USER_ERROR);
return false;
}
//
// OPEN/CLOSE DEVICE SECTION -- {STOP}
//
//
// CONFIGURE SECTION -- {START}
//
/**
* Configure the Baud Rate
* Possible rates : 110, 150, 300, 600, 1200, 2400, 4800, 9600, 38400,
* 57600 and 115200.
*
* @param int $rate the rate to set the port in
* @return bool
*/
function confBaudRate ($rate)
{
if ($this->_dState !== SERIAL_DEVICE_SET)
{
trigger_error("Unable to set the baud rate : the device is either not set or opened", E_USER_WARNING);
return false;
}
$validBauds = array (
110 => 11,
150 => 15,
300 => 30,
600 => 60,
1200 => 12,
2400 => 24,
4800 => 48,
9600 => 96,
19200 => 19,
38400 => 38400,
57600 => 57600,
115200 => 115200
);
if (isset($validBauds[$rate]))
{
if ($this->_os === "linux")
{
$ret = $this->_exec("stty -F " . $this->_device . " " . (int) $rate, $out);
}
if ($this->_os === "darwin")
{
$ret = $this->_exec("stty -f " . $this->_device . " " . (int) $rate, $out);
}
elseif ($this->_os === "windows")
{
$ret = $this->_exec("mode " . $this->_windevice . " BAUD=" . $validBauds[$rate], $out);
}
else return false;
if ($ret !== 0)
{
trigger_error ("Unable to set baud rate: " . $out[1], E_USER_WARNING);
return false;
}
}
}
/**
* Configure parity.
* Modes : odd, even, none
*
* @param string $parity one of the modes
* @return bool
*/
function confParity ($parity)
{
if ($this->_dState !== SERIAL_DEVICE_SET)
{
trigger_error("Unable to set parity : the device is either not set or opened", E_USER_WARNING);
return false;
}
$args = array(
"none" => "-parenb",
"odd" => "parenb parodd",
"even" => "parenb -parodd",
);
if (!isset($args[$parity]))
{
trigger_error("Parity mode not supported", E_USER_WARNING);
return false;
}
if ($this->_os === "linux")
{
$ret = $this->_exec("stty -F " . $this->_device . " " . $args[$parity], $out);
}
else
{
$ret = $this->_exec("mode " . $this->_windevice . " PARITY=" . $parity{0}, $out);
}
if ($ret === 0)
{
return true;
}
trigger_error("Unable to set parity : " . $out[1], E_USER_WARNING);
return false;
}
/**
* Sets the length of a character.
*
* @param int $int length of a character (5 <= length <= 8)
* @return bool
*/
function confCharacterLength ($int)
{
if ($this->_dState !== SERIAL_DEVICE_SET)
{
trigger_error("Unable to set length of a character : the device is either not set or opened", E_USER_WARNING);
return false;
}
$int = (int) $int;
if ($int < 5) $int = 5;
elseif ($int > 8) $int = 8;
if ($this->_os === "linux")
{
$ret = $this->_exec("stty -F " . $this->_device . " cs" . $int, $out);
}
else
{
$ret = $this->_exec("mode " . $this->_windevice . " DATA=" . $int, $out);
}
if ($ret === 0)
{
return true;
}
trigger_error("Unable to set character length : " .$out[1], E_USER_WARNING);
return false;
}
/**
* Sets the length of stop bits.
*
* @param float $length the length of a stop bit. It must be either 1,
* 1.5 or 2. 1.5 is not supported under linux and on some computers.
* @return bool
*/
function confStopBits ($length)
{
if ($this->_dState !== SERIAL_DEVICE_SET)
{
trigger_error("Unable to set the length of a stop bit : the device is either not set or opened", E_USER_WARNING);
return false;
}
if ($length != 1 and $length != 2 and $length != 1.5 and !($length == 1.5 and $this->_os === "linux"))
{
trigger_error("Specified stop bit length is invalid", E_USER_WARNING);
return false;
}
if ($this->_os === "linux")
{
$ret = $this->_exec("stty -F " . $this->_device . " " . (($length == 1) ? "-" : "") . "cstopb", $out);
}
else
{
$ret = $this->_exec("mode " . $this->_windevice . " STOP=" . $length, $out);
}
if ($ret === 0)
{
return true;
}
trigger_error("Unable to set stop bit length : " . $out[1], E_USER_WARNING);
return false;
}
/**
* Configures the flow control
*
* @param string $mode Set the flow control mode. Availible modes :
* -> "none" : no flow control
* -> "rts/cts" : use RTS/CTS handshaking
* -> "xon/xoff" : use XON/XOFF protocol
* @return bool
*/
function confFlowControl ($mode)
{
if ($this->_dState !== SERIAL_DEVICE_SET)
{
trigger_error("Unable to set flow control mode : the device is either not set or opened", E_USER_WARNING);
return false;
}
$linuxModes = array(
"none" => "clocal -crtscts -ixon -ixoff raw",
"rts/cts" => "-clocal crtscts -ixon -ixoff",
"xon/xoff" => "-clocal -crtscts ixon ixoff"
);
$windowsModes = array(
"none" => "xon=off octs=off rts=on",
"rts/cts" => "xon=off octs=on rts=hs",
"xon/xoff" => "xon=on octs=off rts=on",
);
if ($mode !== "none" and $mode !== "rts/cts" and $mode !== "xon/xoff") {
trigger_error("Invalid flow control mode specified", E_USER_ERROR);
return false;
}
if ($this->_os === "linux")
$ret = $this->_exec("stty -F " . $this->_device . " " . $linuxModes[$mode], $out);
else
$ret = $this->_exec("mode " . $this->_windevice . " " . $windowsModes[$mode], $out);
if ($ret === 0) return true;
else {
trigger_error("Unable to set flow control : " . $out[1], E_USER_ERROR);
return false;
}
}
/**
* Sets a setserial parameter (cf man setserial)
* NO MORE USEFUL !
* -> No longer supported
* -> Only use it if you need it
*
* @param string $param parameter name
* @param string $arg parameter value
* @return bool
*/
function setSetserialFlag ($param, $arg = "")
{
if (!$this->_ckOpened()) return false;
$return = exec ("setserial " . $this->_device . " " . $param . " " . $arg . " 2>&1");
if ($return{0} === "I")
{
trigger_error("setserial: Invalid flag", E_USER_WARNING);
return false;
}
elseif ($return{0} === "/")
{
trigger_error("setserial: Error with device file", E_USER_WARNING);
return false;
}
else
{
return true;
}
}
//
// CONFIGURE SECTION -- {STOP}
//
//
// I/O SECTION -- {START}
//
/**
* Sends a string to the device
*
* @param string $str string to be sent to the device
* @param float $waitForReply time to wait for the reply (in seconds)
*/
function sendMessage ($str, $waitForReply = 0.1)
{
$this->_buffer .= $str;
if ($this->autoflush === true) $this->serialflush();
usleep((int) ($waitForReply * 1000000));
}
/**
* Reads the port until no new datas are availible, then return the content.
*
* @pararm int $count number of characters to be read (will stop before
* if less characters are in the buffer)
* @return string
*/
function readPort ($count = 0)
{
if ($this->_dState !== SERIAL_DEVICE_OPENED)
{
trigger_error("Device must be opened to read it", E_USER_WARNING);
return false;
}
if ($this->_os === "linux" || $this->_os === "osx")
{
// Behavior in OSX isn't to wait for new data to recover, but just grabs what's there!
// Doesn't always work perfectly for me in OSX
$content = ""; $i = 0;
if ($count !== 0)
{
do {
if ($i > $count) $content .= fread($this->_dHandle, ($count - $i));
else $content .= fread($this->_dHandle, 128);
} while (($i += 128) === strlen($content));
}
else
{
do {
$content .= fread($this->_dHandle, 128);
} while (($i += 128) === strlen($content));
}
return $content;
}
elseif ($this->_os === "windows")
{
/* Do nothing : not implented yet */
}
trigger_error("Reading serial port is not implemented for Windows", E_USER_WARNING);
return false;
}
/**
* Flushes the output buffer
* Renamed from flush for osx compat. issues
*
* @return bool
*/
function serialflush ()
{
if (!$this->_ckOpened()) return false;
if (fwrite($this->_dHandle, $this->_buffer) !== false)
{
$this->_buffer = "";
return true;
}
else
{
$this->_buffer = "";
trigger_error("Error while sending message", E_USER_WARNING);
return false;
}
}
//
// I/O SECTION -- {STOP}
//
//
// INTERNAL TOOLKIT -- {START}
//
function _ckOpened()
{
if ($this->_dState !== SERIAL_DEVICE_OPENED)
{
trigger_error("Device must be opened", E_USER_WARNING);
return false;
}
return true;
}
function _ckClosed()
{
if ($this->_dState !== SERIAL_DEVICE_CLOSED)
{
trigger_error("Device must be closed", E_USER_WARNING);
return false;
}
return true;
}
function _exec($cmd, &$out = null)
{
$desc = array(
1 => array("pipe", "w"),
2 => array("pipe", "w")
);
$proc = proc_open($cmd, $desc, $pipes);
$ret = stream_get_contents($pipes[1]);
$err = stream_get_contents($pipes[2]);
fclose($pipes[1]);
fclose($pipes[2]);
$retVal = proc_close($proc);
if (func_num_args() == 2) $out = array($ret, $err);
return $retVal;
}
//
// INTERNAL TOOLKIT -- {STOP}
//
}
Un saludo!
