It is easy integrate DHT11 temperature and humidity sensor with Arduino Uno board. You can find enough resources in the web how to connect DHT11 with Arduino.
Measured temperature and humidity can publish to a Web via APIs supported by cosm.com.
You can find the working code in the Github.
When you upload the program to Arduino UNO board you may get an error saying
“Serial port ‘/dev/ttyACM0’ not found. Did you select the right one from the Tools > Serial Port menu?“
This error occurs when user do not have write privileges to device /dev/ttyACM0. User can fix this issue by giving enough rights to user or simply give all writes to the device. ( chmod 777 /dev/ttyACM0 [this is a hack ;)])
Apache Hadoop 1.0.0 released. Release Note
Hadoop 1.0.0 released from 0.20.2xx.x development tree. There is another new development in Hadoop space with version 0.23.0. New 0.23.0 version contains HDFS Federation and NextGen MapReduce (YARN).
Ubuntu 11.10 released with the Linux 3.0.0. Now Linux has the Xen dom0 support.
1. Install Xen hypervisor
apt-get install xen-hypervisor-4.1-amd64
2. create a domU configuration. ( node0.cfg )
disk = [ 'file:/mnt/vm/xen/vm_images/node0.iso,hda,w', 'file:/media/mnt/vm/xen/iso_files/oneiric-desktop-i386.iso,hdc:cdrom,r' ] memory=1024 vcpus=1 name="node0" vif=[ 'type=ioemu,bridge=virbr0' ] builder = "hvm" device_model = "/usr/lib/xen-4.1/bin/qemu-dm" vnc=1 vncunused=1 apic=0 acpi=0 pae=0 serial = "pty" # enable serial console boot="dc" on_reboot = 'restart' on_crash = 'restart'
3. Start the domain
xm create /pathto/node0.cfg
In the first boot vm boots from cdrom and user can install new OS to vm.
by changing the boot order to boot=”c” user can boot from the hard disk.
4. List running domains.
Ubuntu 11.10 still need some path fixes to run user domains /vms ( domU ).
You may get an error in your /var/log/qemu-dm-node0.log saying :
Could not read keymap file: ‘/usr/share/qemu/keymaps/en-us’
create symbolic link named qemu-linaro in /usr/share with the name qemu.
For bridge networks default bridge may not include your default NIC.
If your vms ( domUs ) can not communicate with out side networks add
NIC to bridge.
brctl addif virbr0 eth0
WSO2 CSS is Column ( Family Data ) Store based on Apache Cassandra . WSO2 CSS can deploy with any WSO2 Carbon based product and it is available as a service in StratosLive the PaaS offering of WSO2.
It is very easy to use CSS as a data store with widely available connectors like java based Hector and other thrift based connectors. StratosLive supports Hector API to communicate with the Cassanda based back-end CSS cluster. External applications can use StratosLive PaaS column data store feature with any Cassandra connector.
StratosLive app developers have to use tenant information to authenticate in the connection with CSS data store. Tenant admin can create tenant and authorize the user for data store access.
This sample create connection to StratosLive CSS as an external application. It writes random data to StratosLive CSS keyspace and read and output date via stdout.
Instructions to build and run the sample.
Build the project with Maven
Take a copy of the source using svn
mvn clean install
Build the project with dependency libraries
mvn clean assembly:assembly -o
Execute the program
java -jar target/org.wso2.carbon.cassandra.examples-3.2.1-jar-with-dependencies.jar
WSO2Con 2011 is happening in Colombo Sri Lanka between Sep 12 – 16 at Waters Edge. WSO2Con 2011 is the second WSO2 developer conference and it is more focus on new WSO2 PaaS offering named Stratos and the hosted service StratosLive.
WSO2Con 2011 main conference starts on 13th Sep and ends on 15th Sep. There are pre-conference tutorials and post conference tutorials to get real experience of the WSO2 product stack. Each conference day has two tracks therefore participants can select talks based on the interests. Check the conference agenda early and select the track.
In this year conference WSO2 customers and partners are presenting their solutions developed with WSO2 products.