Embedded Linux

How to switch between java versions in linux? (older or newer version selection). 1. First check what  is the version is already been installed on your host by issuing command $java -version then you will see something like below OpenJDK Runtime Environment (build 1.6.0-b09) OpenJDK Client VM (build 1.6.0-b09, mixed mode) This gives you the current version of java you are using. 2.If you have more than one java versions installed on host then enter following command $update-alternative --config java this will give you the following output 1. /usr/lib/jvm/jre-1.4.2-gcj/bin/java *+ 2 /usr/lib/jvm/jre-1.6.0-openjdk/bin/java Enter to keep the current selection[+], or type selection number: Here the * indicates currently which java version you are using. you can input selection number to switch between two. Thanks, Shrenik. Have a look on my interview with EEWeb online international community

  This is a simple approach to see how to implement zigbee based water irrigation control for irrigation system. This is not a difficult thing to get control over motor and electromagnetic valves using zigbee and MCU. I am not going to provide detailed steps how its implemented as code provided is with lot of comments. The idea is we can control the electromagnetic valves and motor depending on the moister content in the farm area and the water level in the water source (water well). Its somewhat advanced technique which requires PC/laptop for manual control. This system is having both manual and automatic control. For manual control you can control valves and motor from remote place, and for automatic control the simple moister sensor like this can be used. That moister sensor will give digital logic output based on whether soil is wet or dry. If its dry and the water level is good then motor and respective valve will get turned on. Now to setup communication between two zigbee mo...