IntroductionIn this assignment you are going to develop a Java client/server application that sends and receives temperature data to/from a PC and an embedded Linux device such as the BeagleBone Black (BBB) or Raspberry Pi (RPi). This assignment requires a fair amount of configuration before you begin the assignment. Please send questions on problems that you are having to the mailing list on the module Loop page. The assignment is worth 15% of your overall mark in the module and therefore represents a significant body of work. The assignment begins with steps to set up your BBB/RPi to access the Internet, to flash the user LEDs using C, to install Java and finally to flash the user LEDs using Java. Good luck! Derek. Background Setup and Configuration (BBB and RPi)Follow the steps in this guide to place the BeagleBone Black (BBB) or Raspberry Pi (RPi) on the Internet so that you can clone the repository of source code on the Github site. Please note that access to the Internet from your board is useful, but it is not vital -- you can transfer files from your PC to the boards if necessary. BeagleBone Steps (See below for RPi steps)BeagleBone Only Step 1. BeagleBone Network Configuration and Source CodeFor the BBB, please read: Please note that for Windows 10 you will have to download the BeagleBone drivers from: http://beagleboard.org/getting-started If you have completed this guide successfully, you should be able to perform the following tasks: root@beaglebone:~# ping 8.8.8.8 PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. 64 bytes from 8.8.8.8: icmp_req=1 ttl=50 time=14.0 ms 64 bytes from 8.8.8.8: icmp_req=2 ttl=50 time=13.8 ms ...
root@beaglebone:~# ping www.google.com PING www.google.com (173.194.45.144) 56(84) bytes of data. 64 bytes from www.google.com (173.194.45.144): icmp_req=1 ttl=51 time=58.2 ms 64 bytes from www.google.com (173.194.45.144): icmp_req=2 ttl=51 time=58.2 ms ... NOTE: If you are using Internet-over-USB often on the BBB then you can edit your ~/.profile file using nano and add the following lines to the bottom of the file: /sbin/route add default gw 192.168.7.1 /usr/sbin/ntpdate -b -s -u ie.pool.ntp.org Next, you should clone the EE402 source code repository, as follows: root@beaglebone:~# cd ~/ root@beaglebone:~# git clone https://github.com/derekmolloy/ee402.git Cloning into 'ee402'... remote: Counting objects: 276, done. remote: Total 276 (delta 0), reused 0 (delta 0) Receiving objects: 100% (276/276), 726.80 KiB | 248 KiB/s, done. Resolving deltas: 100% (96/96), done.
root@beaglebone:~# cd ee402/
root@beaglebone:~/ee402# ls LEDcpp LICENSE notes_examples testcpp tmp36 LEDjava README.md scripts testjava ... BeagleBone Only Step 2. Using the BeagleBone User LEDsFollow the guide at: https://sites.google.com/site/derekmolloyee402/home/embedded-linux/flashing-the-leds-using-c You can access the code for this guide in the ee402 repository directory as follows: root@beaglebone:~# cd ~/ee402 root@beaglebone:~/ee402# cd LEDcpp/ root@beaglebone:~/ee402/LEDcpp# ls -al total 32 drwxr-xr-x 2 root root 4096 Nov 17 15:58 . drwxr-xr-x 10 root root 4096 Nov 17 15:59 .. -rwxr-xr-x 1 root root 124 Nov 17 15:58 build -rwxr-xr-x 1 root root 13955 Nov 17 15:58 makeLED -rw-r--r-- 1 root root 1834 Nov 17 15:58 makeLED.cpp root@beaglebone:~/ee402/LEDcpp# ./build EE402 - Building the Test LED program on the Beaglebone Black Finished root@beaglebone:~/ee402/LEDcpp# ./makeLED flash Starting the LED flash program The LED Path is: /sys/class/leds/beaglebone:green:usr0 Finished the LED flash program root@beaglebone:~/ee402/LEDcpp# ./makeLED off Starting the LED flash program The LED Path is: /sys/class/leds/beaglebone:green:usr0 Finished the LED flash program There is a Java version of this code in ~/ee402/LEDjava but leave it alone for the moment. Please note that to control the RPi LEDs use the path /sys/class/leds/ and then the name of the led that you wish to control. BeagleBone Only Step 3. Installing Java on the BeagleBonehttps://sites.google.com/site/derekmolloyee402/home/embedded-linux/flashing-the-leds-using-java Use the same steps in this video and download the Java SE 8 version for Linux ARM 32 Hard Float ABI, which is available at the link: http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html Transfer the downloaded gz file to the BBB using the steps in the video to install Java 7 and the steps below this describe the settings required for Java 8. Figure 1 illustrates my FTP screen for the latest version of Java and the commands I used to transfer the file to the BBB using psftp. The installation of PuTTY that is described in the video is the reason that I have a psftp command. Now, test that the version of Java is working correctly: root@beaglebone:/usr/java# ls ejdk1.8.0_06 root@beaglebone:/usr/java# cd ejdk1.8.0_06/ root@beaglebone:/usr/java/ejdk1.8.0_06# cd linux_arm_vfp_hflt/ root@beaglebone:/usr/java/ejdk1.8.0_06/linux_arm_vfp_hflt# cd jre/bin root@beaglebone:/usr/java/ejdk1.8.0_06/linux_arm_vfp_hflt/jre/bin# ls java keytool pack200 rmid servertool unpack200 jjs orbd policytool rmiregistry tnameserv root@beaglebone:/usr/java/ejdk1.8.0_06/linux_arm_vfp_hflt/jre/bin# ./java -version java version "1.8.0_06" Java(TM) SE Embedded Runtime Environment (build 1.8.0_06-b23) Java HotSpot(TM) Embedded Client VM (build 25.6-b23, mixed mode) Next, you need to add two environment variables so that the JRE can be found in your PATH and so that the JRE will be able to find the location of its installation files, JAVA_HOME, which contains the runtime libraries (note: you can use the Tab key to auto-complete): root@beaglebone:# export PATH=$PATH:/usr/java/ejdk1.8.0_06/linux_arm_vfp_hflt/jre/bin root@beaglebone:# export JAVA_HOME=/usr/java/ejdk1.8.0_06/linux_arm_vfp_hflt/jre root@beaglebone:/usr/java# echo $PATH /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/java/ejdk1.8.0_06/linux_arm_vfp_hflt/jre/bin root@beaglebone:/usr/java# echo $JAVA_HOME /usr/java/ejdk1.8.0_06/linux_arm_vfp_hflt/jre
Now, Java works from any point on your BBB using these environment variables. Add the lines: export PATH=$PATH:/usr/java/ejdk1.8.0_06/linux_arm_vfp_hflt/jre/bin export JAVA_HOME=/usr/java/ejdk1.8.0_06/linux_arm_vfp_hflt/jre to your ~/.profile file by using nano. My ~/.profile file now looks like this (The source command allows you to reload the profile without having to log out and back in again): root@beaglebone:~# cd ~/ root@beaglebone:~# nano .profile root@beaglebone:~# more .profile # ~/.profile: executed by Bourne-compatible login shells. if [ "$BASH" ]; then if [ -f ~/.bashrc ]; then . ~/.bashrc fi fi mesg n export PATH=$PATH:/usr/java/ejdk1.8.0_06/linux_arm_vfp_hflt/jre/bin export JAVA_HOME=/usr/java/ejdk1.8.0_06/linux_arm_vfp_hflt/jre /sbin/route add default gw 192.168.7.1 /usr/sbin/ntpdate -b -s -u ie.pool.ntp.org
root@beaglebone:~# source ~/.profile SIOCADDRT: File exists root@beaglebone:~# java -version java version "1.8.0_06" Java(TM) SE Embedded Runtime Environment (build 1.8.0_06-b23) Java HotSpot(TM) Embedded Client VM (build 25.6-b23, mixed mode) BeagleBone Only Step 5. Testing the Java LED code on the BBBIf everything is working correctly, the Java LED example should now work from the code repository using the following steps (Please adapt the path for the RPi code): root@beaglebone:~# cd ~/ee402/ root@beaglebone:~/ee402# cd LEDjava root@beaglebone:~/ee402/LEDjava# ls README bin src root@beaglebone:~/ee402/LEDjava# cd bin root@beaglebone:~/ee402/LEDjava/bin# cd ee402/ root@beaglebone:~/ee402/LEDjava/bin/ee402# ls BasicLEDExample.class root@beaglebone:~/ee402/LEDjava/bin/ee402# cd .. root@beaglebone:~/ee402/LEDjava/bin# java ee402.BasicLEDExample On root@beaglebone:~/ee402/LEDjava/bin# java ee402.BasicLEDExample Off Raspberry Pi StepsRPi Only Step 1: Network Configuration and Source CodeYou need a network patch cable in order to complete these steps and one of the following configurations:
Please note that if everything goes wrong, you can connect the RPi to a monitor and keyboard and boot it as a regular PC. You can then change the network settings using the GUI tools. In the second case you need to share your wireless network adapter. Use START->Network and Sharing Center->Change Adapter Settings->Right-Click your Wi-Fi adapter -> Properties then click on the Sharing tab and check the two boxes "Allow other network users to connect..." and "Allow other network users to control...". Reboot the RPi. At this point you should be able to:
pi@raspberrypi: $ cd ~/ pi@raspberrypi: $ git clone https://github.com/derekmolloy/ee402.git Cloning into 'ee402'... remote: Counting objects: 276, done. remote: Total 276 (delta 0), reused 0 (delta 0) Receiving objects: 100% (276/276), 726.80 KiB | 248 KiB/s, done. Resolving deltas: 100% (96/96), done.
pi@raspberrypi: $ cd ee402/
pi@raspberrypi: /ee402$ ls LEDcpp LICENSE notes_examples testcpp tmp36 LEDjava README.md scripts testjava ...
RPi Only Step 2. Using the User LEDYou can access the code for this guide in the ee402 repository directory to see how the same thing is achieved on the BeagleBone (as above). Everything is the same except that the path is different. The path is /sys/class/leds/led0. RPi Only Step 3. Installing JavaJava is installed on the default Raspbian image as standard. Equipment for the Assignment.No external sensors or wiring required. You can use the CPU temperature as the sensor input for this assignment. On the RPi the CPU temperature of the board is available at the location: /sys/class/thermal/thermal_zone0/temp For example, to measure the CPU temperature you can read the value as follows:
On the BeagleBone the CPU temperature is available at: /sys/class/hwmon/hwmon0/device/temp1_input If this file entry is not available on your BeagleBone (this will happen if you have installed the latest image) then please use the CPU utilization instead of the CPU temperature for your assignment. You can do this by reading the first line of the file /proc/stat, which will look something like: root@beaglebone:/sys# more /proc/stat cpu 3270 0 2974 46877 268 0 68 0 0 0 ... You do have to do a small amount of coding to get the CPU utilization:
So, in my example above, the cpu utilization is: 12.31% (i.e., 100 x (1 - (46877 / (3270 + 2974 + 46877 + 268 + 68)))) The Embedded Linux Client/Server Temperature Graphing Service In this assignment you should build a temperature sensor client/server application, where the embedded SBC reads the CPU core temperature from a file system entry and sends the data to a desktop computer client, which displays the data in a graphical form. The PC Temperature Graphical ClientIn this application the desktop PC is the graphical temperature client. It connects to the server port on the BBB/RPi boards. The server application executes on the BBB/RPi (as below) and it will provide temperature data (or CPU utilization data) to the client on the PC. The client will then display the data in a full-featured Graphical User Interface (GUI). The PC Temperature client should have the following features:
Remember that the server can connect to multiple clients at the same time so design your client/server appropriately. For example,
The RPi/BBB Embedded Linux Temperature Server In this application the server application should run on the embedded device (Beaglebone/RPi etc.) The server should have the following features:
Code Provided!I have provided you with template code and it MUST BE USED AS THE BASIS OF YOUR SOLUTION. Do *not* use RMI or any other Java Messaging Protocols, only use the template code provided for network communication. This code is available on the web page: Marking You will receive marks for implementing the features above. You will gain marks for making the server threaded, using Swing, for sending suitable messaging objects and for a working solution. You will gain marks for novel/extra features as outlined in the specification. The assignment is worth 15% of your final result. The marks will be broken down into Design, Implementation/Coding and Documentation:
Submission Instructions
Submit the assignment to: https://loop.dcu.ie/mod/assign/view.php?id=1153224 I will discuss the assignment in more detail over the next few weeks. But please start working through the Java notes, particularly in relation to the user interfaces sections. Yes, it likely sounds difficult but you will get through it. I will be giving out additional hints and tips on how to complete this assignment during the coming lectures. Good luck! Derek. |
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