added receive_blink_ros example, this can help to get ROS interfaced with arduino an CAN

examples/send_Blink_ROS/send_Blink_ROS.ino

@@ -0,0 +1,63 @@
+// demo: CAN-BUS Shield, send data
+#include <mcp_can.h>
+#include <SPI.h>
+
+//ROS
+#include <ros.h>
+#include <std_msgs/Empty.h>
+
+ros::NodeHandle  nh;
+
+const int SPI_CS_PIN = 9;
+const int ledHIGH=1;
+const int ledLOW=0;
+unsigned char stmp[8] = {ledHIGH, 1, 2, 3, ledLOW, 5, 6, 7};
+
+MCP_CAN CAN(SPI_CS_PIN);                                    // Set CS pin
+
+void messageCb( const std_msgs::Empty& toggle_msg){
+  //digitalWrite(13, HIGH-digitalRead(13));   // blink the led
+  // send data:  id = 0x00, standrad frame, data len = 8, stmp: data buf
+  CAN.sendMsgBuf(0x70,0, 8, stmp);
+  delay(1000);                       // send data per 100ms
+}
+
+ros::Subscriber<std_msgs::Empty> sub("toggle_led", &messageCb );
+
+// the cs pin of the version after v1.1 is default to D9
+// v0.9b and v1.0 is default D10
+
+
+
+void setup()
+{
+    Serial.begin(115200);
+    nh.initNode();
+    nh.subscribe(sub);
+
+START_INIT:
+
+    if(CAN_OK == CAN.begin(CAN_500KBPS))                   // init can bus : baudrate = 500k
+    {
+        Serial.println("CAN BUS Shield init ok!");
+    }
+    else
+    {
+        Serial.println("CAN BUS Shield init fail");
+        Serial.println("Init CAN BUS Shield again");
+        delay(100);
+        goto START_INIT;
+    }
+}
+
+
+void loop()
+{   
+    
+    nh.spinOnce();
+    delay(1);
+}
+
+/*********************************************************************************************************
+  END FILE
+*********************************************************************************************************/