update sdk document

README.md

@@ -46,11 +46,18 @@ How to build YDLIDAR SDK samples
     $ cd ydlidar_sdk
 
     $ git checkout master
-
-    $ cd ..
+
 
 Linux:
 
+    $ cd startup
+
+    $ chmod +x initenv.sh
+
+    $ sudo ./initenv.sh  ##change the serial port to be readable and writable
+
+    $ cd ../..
+
     $ mkdir build
 
     $ cd build

startup/initenv.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+echo  'KERNEL=="ttyUSB[1-9]*", MODE:="0666", GROUP:="dialout"' >/etc/udev/rules.d/50-usb-serial.rules.rules
+echo  'KERNEL=="ttyUSB*", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea60", MODE:="0666", GROUP:="dialout",  SYMLINK+="ydlidar"' >/etc/udev/rules.d/ydlidar.rules
+echo  'KERNEL=="ttyACM*", ATTRS{idVendor}=="0483", ATTRS{idProduct}=="5740", MODE:="0666", GROUP:="dialout",  SYMLINK+="ydlidar"' >/etc/udev/rules.d/ydlidar-V2.rules
+echo  'KERNEL=="ttyUSB*", ATTRS{idVendor}=="067b", ATTRS{idProduct}=="2303", MODE:="0666", GROUP:="dialout",  SYMLINK+="ydlidar"' >/etc/udev/rules.d/ydlidar-2303.rules
+
+service udev reload
+sleep 2
+service udev restart