checkout addtocart events Observer im magento

/app/code/local/Cart/Cart/etc/config.xml

<?xml version="1.0"?>
<config>
  <modules>
    <Cart_Cart>
      <version>0.1.0</version>
    </Cart_Cart>
  </modules>
  <frontend>
<events>
            <checkout_cart_product_add_after>
                <observers>
                   <Cart_Cart_Model_Observer>
                      <type>singleton</type>
                      <class>Cart_Cart_Model_Observer</class>
                      <method>addtocart</method>
                   </Cart_Cart_Model_Observer>
               </observers>
            </checkout_cart_product_add_after>
        </events>

    <routers>
      <cart>
        <use>standard</use>
          <args>
            <module>Cart_Cart</module>
            <frontName>cart</frontName>
          </args>
      </cart>
    </routers>
<layout>
 <updates>
<cart>
 <file>cart.xml</file>
</cart>
 </updates>
</layout>
  </frontend>
  <global>
    <helpers>
      <cart>
        <class>Cart_Cart_Helper</class>
      </cart>
    </helpers>
<blocks>
 <cart>
<class>Cart_Cart_Block</class>
 </cart>
</blocks>
  </global>
</config>



/app/code/local/Cart/Cart/Model/Observer.php

<?php

class Cart_Cart_Model_Observer {
public function addtocart($observer) {
print_r($_REQUEST);

echo $event = $observer->getEvent(); //Fetches the current event
die('Test Grip');
echo $product = $event->getProduct();

$eventmsg = "Current Event Triggered : " . $event->getName() . "
Currently Added Product : " . $product->getName();
//Adds Custom message to shopping cart
echo Mage::getSingleton("checkout/session")->addSuccess($eventmsg);
//Your Custom Logic Here
//you can use print_r($product) here to get more details
}
}
?>