Intel IoT Gateways: Pulling Data from a Temperature Sensor Using a Python Script

Transcription

1 Intel IoT Gateways: Pulling Data from a Temperature Sensor Using a Python Script Order No.:

2 By using this document, in addition to any agreements you have with Intel, you accept the terms set forth below. You may not use or facilitate the use of this document in connection with any infringement or other legal analysis concerning Intel products described herein. You agree to grant Intel a non-exclusive, royalty-free license to any patent claim thereafter drafted which includes subject matter disclosed herein. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. All information provided here is subject to change without notice. Contact your Intel representative to obtain the latest product specifications and roadmaps. Intel may make changes to specifications and product descriptions at any time, without notice. Designers must not rely on the absence or characteristics of any features or instructions marked "reserved" or "undefined". Intel reserves these for future definition and shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to them. The information here is subject to change without notice. Do not finalize a design with this information. The products described in this document may contain design defects or errors known as errata which may cause the product to deviate from published specifications. Current characterized errata are available on request. Intel processor numbers are not a proxy for performance. Processor numbers differentiate features within a processor family, not across different processor families. Learn more at: The sample code in this document is provided AS IS without warranty of any kind. Intel disclaims all implied warranties including, without limitation, any implied warranties of merchantability or of fitness for a particular purpose. The entire risk arising out of the use or performance of the sample and documentation remains with you. In no event shall Intel, its authors, or anyone else involved in the creation, production, or delivery of the code be liable for any damages whatsoever (including, without limitation, damages for loss of business profits, business interruption, loss of business information, or other pecuniary loss) arising out of the use of or inability to use the sample code or documentation, even if Intel has been advised of the possibility of such damages. Intel, the Intel logo, Intel Atom, Intel Core and Intel Quark, are trademarks of Intel Corporation in the U.S. and/or other countries. Wind River is a trademark of Wind River Systems, Inc. *Other names and brands may be claimed as the property of others. Copyright 2015, Intel Corporation. All rights reserved. 2 Order No.:

3 Revision History Intel IoT Gateway Revision History Date Revision Description 001 Initial public release Order No.:

4 Intel IoT Gateway Contents Contents Revision History Introduction Create the Directory Structure Create the Sample Application Create the BitBake Recipe Set Up Phidgets Libraries Build and Install Gateway Operating System Image Connect and Test the Temperature Sensor Conclusion Development Suggestions Order No.:

5 Introduction Intel IoT Gateway 1.0 Introduction Note: For an online version of this document, see SetupGateway-PullSensorData-Python Applicable to These Intel IoT Gateway Products Intel IoT Gateways based on Intel Atom processors Intel IoT Gateways based on Intel Core processors Intel IoT Gateways based on Intel Quark processors How These Instructions Help You These instructions will guide you through the steps to create and install a custom Wind River Linux 7 OS image that includes the software and libraries necessary to interface a Phidgets* temperature sensor with your Intel IoT Gateway using Python. Then, it will show how to attach the temperature sensor and run an example Python application that pulls temperature data from the temperature sensor and stores it locally on the Gateway. Sensor Hardware You Need to Provide You need the following components: Phidgets Precision Temperature Sensor. Part #1124_0: Phidgets Interface Kit 8/8/8. Part # 1018_2: Order No.: Intel IoT Gateways: Pulling Data from a Temperature Sensor Using a Python Script 5

6 Intel IoT Gateway Introduction Pre-Requisites Your Gateway hardware must be set up. See SetupGateway-hardware Your Wind River development environment must be installed and configured on your Development Computer. See DevelopmentTools Required Experience Level This guide assumes you have experience with: Executing Linux commands. Creating, editing, and executing scripts. Installing and configuring Linux software. Using a terminal emulation program like PuTTY* with serial connections between computers. Document Terminology and Conventions Terminology Gateway: An Intel IoT Gateway. Development Computer: Linux computer that you provide to develop applications for your Gateway. Ubuntu* Base is preferred. Conventions This font is used for commands, API names, parameters, filenames, directory paths, and executables. Bold text is used for graphical user interface entries, buttons, and keyboard keys. This font in a gray box is used for commands you must type or include in a script. Where to Perform These Steps Begin these instructions in the $HOME/Project directory on your Development Computer. 6 Order No.:

7 Create the Directory Structure Intel IoT Gateway 2.0 Create the Directory Structure 1. When you set up your development environment, you created a script file called config.sh in the $HOME/Project directory on your Development Computer. Edit config.sh to check for and include: --enable-reconfig --without-layer=wr-srm,wr-ima-appraise 2. Create the upper level example directory: mkdir -p $HOME/Project/layers/local/recipes-local 3. Create the directory where the Phidgets libraries will be built: mkdir -p $HOME/Project/layers/local/recipes-local/libphidget 4. Create the directory structure where the Python-specific Phidgits libraries and the example application will be built: mkdir -p $HOME/Project/layers/local/recipes-local/PhidgetsPython/files Order No.:

8 Intel IoT Gateway Create the Sample Application 3.0 Create the Sample Application 1. Change to the example application directory: cd $HOME/Project/layers/local/recipes-local/PhidgetsPython/files 2. Create a file called pytemp.py and copy/paste the following contents into it: #! /usr/bin/python import sys import datetime from time import time, sleep from Phidgets. Devices. InterfaceKit import * from Phidgets. Devices. TemperatureSensor import * TEMP_SENSOR_PORT = 6 # Define an error catching function so we can call it on "try...except" blocks def LocalErrorCatcher( event ): print ( "Phidget Exception: " + str(e.code) + " - " + str(e.details) + ", Exiting..." ) exit(1) # Get the temperature sensor reading from port #TEMP_SENSOR_PORT of the Sensor Kit def GetTemp( device, outfile, TEMP_SENSOR_PORT ): current_time = datetime. datetime.now() # Get the board temperature in Celsius by reading sensor input and applying conversion formula ambienttemp = ( device.getsensorvalue( TEMP_SENSOR_PORT ) *.2222) # Write the data to the text file time_and_temp = (str(current_time) + ", " + str(ambienttemp) + "\n" ) print ( "%s" % time_and_temp) outfile.write(time_and_temp) sys.stdout.flush() # Clear and open the data file for writing outfile = open( "phidgets_temperature_data.txt", "w" ) # Write a header to the text file first thing outfile.write( "Time Sensor Temperature (C)\n" ) # Connect to Interface Kit and set data sampling rate to 4ms print ( "Opening Phdgets Interface Kit object..." ) try : device = InterfaceKit() except PhidgetException as e: LocalErrorCatcher(e) try : device.openphidget() except PhidgetException as e: 8 Order No.:

9 Create the Sample Application Intel IoT Gateway LocalErrorCatcher(e) try : device.waitforattach(10000) device.setdatarate(temp_sensor_port, 4) except PhidgetException as e: LocalErrorCatcher(e) print ( "%d attached! Now reading temperature every second." % (device.getserialnum())) print ( "Press 'Ctrl + c' to end anytime...\n\n" ); print ( "Time Sensor Temperature (C)\n" ) try : while True : sleep(1) GetTemp(device, outfile, TEMP_SENSOR_PORT) except KeyboardInterrupt: pass print ( "Phidget SensorKit gracefully detached. Exiting." ) device.closephidget() exit(0) Order No.:

10 Intel IoT Gateway Create the BitBake Recipe 4.0 Create the BitBake Recipe 1. Change to the $HOME/Project/layers/local/recipes-local/ PhidgetsPython directory: cd $HOME/Project/layers/local/recipes-local/PhidgetsPython/ 2. Click this link to obtain the filename of the zip file: downloads/libraries/phidgetspython.zip. As of September 15, 2015, the filename is PhidgetsPython_ zip Note: It is not necessary to download or install the file. 3. Use the base part of the filename to create a.bb file with same base name. For example PhidgetsPython_ bb 4. Add the following contents to the.bb file: SUMMARY = "The PhidgetsPython package" DESCRIPTION = "The PhidgetsPython package" HOMEPAGE = " LICENSE = "CC-BY-2.5" SECTION = "devel" # Specify source directory that BitBake uses to build this package. WORKDIR is standard. S = "${WORKDIR}" # You need to checksum the license for this package. Leave the md5sum empty, # and on the first compile pass BitBake will tell you what value to insert. LIC_FILES_CHKSUM = "file://phidgetspython/phidgets/ Phidget.py;beginline=1;endline=5;md5=5ed30fa0f6c0218da12eda933f341a36;" # Here is where you add packages to the build dependencies DEPENDS = "libphidget" # This is the incremental package revision number. You should # increment this value for each new revision to update the build. PR = "r0" # This is where you set the package's upstream location. The file # name at the end of the path is used as the package's.zip name when # searched in the local 'download' directories. SRC_URI = " \ file://pytemp.py" # Here is the checksum attribute for the package's zip file. Leave this empty, # and on the first compile pass BitBake will tell you what md5 value to insert. SRC_URI[md5sum] = "4db33d1f8fc73dc86a32c415a5c47a2f" 10 Order No.:

11 Create the BitBake Recipe Intel IoT Gateway SRC_URI[sha256sum] = "070a9f7da2a99f28c9995f93ee419dbd8474f5caafb e64bca0f8" # Safe default to force a non-parallel build PARALLEL_MAKE = "-j 1" # Individually create and populate directories to house all components of this package do_install() { install -m 777 -d ${D}/root/examples/ install -m 777 -d ${D}/root/examples/PhidgetsPython/ install -m 777 ${WORKDIR}/pytemp.py ${D}/root/examples/ cp -r ${WORKDIR}/PhidgetsPython/* ${D}/root/examples/PhidgetsPython/ } # List of files that BitBake will verify are installed from the do_install() FILES_${PN} = "/root/examples/pytemp.py \ /root/examples/phidgetspython/* \ /root/examples/phidgetspython/phidgets/* \ /root/examples/phidgetspython/phidgets/devices/* \ /root/examples/phidgetspython/phidgets/events/* \ " # Call the setup script after all components are in place. pkg_postinst_${pn} () { #!/bin/sh -e cd /root/examples/phidgetspython python setup.py install } 5. Go to your $HOME/Projects and add the PhidgetsPython package to your Gateway operating system image: cd $HOME/Project make -C build PhidgetsPython.addpkg make -C build PhidgetsPython Ignore warning messages. However, if you see errors about md5 checksums or sha256 checksums, then the library package license has changed. The error message will show the expected values. Copy and paste these expected md5 and sha256 values into the appropriate lines of the bb file, save the file, and retry the make commands. Order No.:

12 Intel IoT Gateway Set Up Phidgets Libraries 5.0 Set Up Phidgets Libraries 1. Change to the directory where the Phidgets libraries will be built: cd $HOME/Project/layers/local/recipes-c-example/libphidget 2. Click this link to obtain the filename of the tar.gz file: downloads/libraries/libphidget.tar.gz. As of October 20, 2015, the filename is libphidget_ tar.gz Note: It is not necessary to download or install the file. The files will be installed when you next run make. 3. Use the base part of the filename to create a.bb file with same base name. For example libphidget_ bb 4. Add these contents to the.bb file: # Basic information about package DESCRIPTION = "Phidgets Library" SECTION = "examples" LICENSE = "GPLv3" LIC_FILES_CHKSUM = "file://copying;md5=d32239bcb673463ab874e80d47fae504" SRC_URI = " SRC_URI[md5sum] = "a1ee9be d70c8304c3ac8" SRC_URI[sha256sum] = "491580b8f8def0cbde55202fe8297e1d811eeaf2014b8b35883f7f86225d2bee" PR = "r0" DEPENDS = "libusb" # Automatically take care of installation and verification using provided configure file inherit autotools 5. Go to your $HOME/Projects directory and add the libphidgets package to your Gateway operating system image: cd $HOME/Project make -C build libphidget.addpkg make -C build libphidget Ignore warning messages. However, if you see errors about md5 checksums or sha256 checksums, then the library package license has changed. The error message will show the expected values. Copy and paste these expected md5 and sha256 values into the appropriate lines of the bb file, save the file, and retry the make commands. 12 Order No.:

13 Build and Install Gateway Operating System Image Intel IoT Gateway 6.0 Build and Install Gateway Operating System Image Build the Gateway OS 1. In the $HOME/Projects directory on your Development Computer, build your Gateway OS image: Note: The make command can take several hours, depending on the speed of your Development Computer. make fs 2. Confirm that the packages were successfully included in the new image by making sure pytemp.py was created: cd $HOME/Project/export/dist/usr/bin/ ls pytemp.py Copy the Gateway OS to USB Flash Drive In this section you will copy your Gateway OS onto a bootable USB flash drive. The USB flash drive must be at least 4 GB and any content on it will be erased. 1. From your Development Computer, display the storage devices: ls /dev/sd? 2. Insert the USB flash drive into your Development Computer. 3. Run ls again and compare the results to determine the newly connected storage device (USB flash drive): ls /dev/sd? You will need the USB flash drive name in the next step. In this example, the USB flash drive is /dev/sdb 4. Change to the $HOME/Project directory: cd $HOME/Project 5. Deploy the Gateway OS to the USB flash drive. The compiled OS file is named to match the processor type in the Gateway. Use the appropriate command for your Gateway and replace??? with the storage device: Order No.:

14 Intel IoT Gateway Build and Install Gateway Operating System Image Intel IoT Gateways based on Intel Atom processors: sudo./deploy.sh -u -f export/intel-baytrail-64-idp-idp-dist.tar.bz2 \ -d /dev/??? -y; sync Intel IoT Gateways based on Intel Core processors: sudo./deploy.sh -u -f export/intel-haswell-64-idp-idp-dist.tar.bz2 \ -d /dev/??? -y; sync Intel IoT Gateways based on Intel Quark processors: sudo./deploy.sh -u -f export/intel-quark-idp-idp-dist.tar.bz2 \ -d /dev/??? -y -u -b cross-hill; sync The deploy process takes about 15 minutes. 6. Type your Linux password if prompted and click OK. The bootable USB drive is created when you see DONE! 7. Remove and reinsert the USB flash drive in your Development Computer. It mounts with two partitions, one of which is /media/<username>/wr_usb_boot. 8. Copy the Gateway OS file to the flash drive. Use the appropriate command for your Gateway and replace <username> with your Linux login name: Intel IoT Gateways based on Intel Atom processors: sudo cp export/intel-baytrail-64-idp-idp-dist.tar.bz2 /media/<username>/ wr_usb_boot/opt/; sync Intel IoT Gateways based on Intel Core processors: sudo cp export/intel-haswell-64-idp-idp-dist.tar.bz2 /media/<username>/ wr_usb_boot/opt/; sync Intel IoT Gateways based on Intel Quark processors: sudo cp export/intel-quark-idp-idp-dist.tar.bz2 /media/<username>/wr_usb_boot/ opt/; sync 9. Remove the USB flash drive from your Development Computer. Install OS on Gateway Perform these steps on the Gateway. Important: Before using these steps, you must set your Gateway's BIOS to boot from the USB flash drive. Instructions for doing this are in the - Appendix: Setup BIOS Boot from USB. See 1. Power down the Gateway, insert the USB flash drive, and then re-apply power. Login using root for the login ID and password. 2. Install the OS. Use the appropriate command for your Gateway: 14 Order No.:

15 Build and Install Gateway Operating System Image Intel IoT Gateway Intel IoT Gateways based on Intel Atom and Core processors tgt=/dev/sda /sbin/reset_media Intel IoT Gateways based on Intel Quark processors /sbin/reset_media When prompted to Restore the boot media to its factory defaults, answer yes. This installation can take up to 20 minutes. Important: If you receive the message ERROR: Unmount /dev/sda1 failed! your Gateway might not have booted from the USB flash drive. Check the boot priority and UEFI settings to ensure the first boot priority is UEFI, using the internal storage device. See "Appendix: Setup BIOS Boot from USB" in 3. Install the OS: /sbin/reset_media When prompted to Restore the boot media to its factory defaults, answer yes. This installation can take up to 20 minutes. Important: If you receive the message ERROR: Unmount /dev/sda1 failed! your Gateway might not have booted from the USB flash drive. Check the boot priority and UEFI settings to ensure the first boot priority is UEFI, using the internal storage device. See "Appendix: Setup BIOS Boot from USB" in 4. Installation is complete when you see the message DONE! Shut down the Gateway: poweroff 5. Remove the USB flash drive and then power up your Gateway. Note: If you see a boot error message, such as Reboot and select proper boot device or similar, ensure the Gateway BIOS has Boot Priority 1 set for: UEFI via internal storage. See "Appendix: Setup BIOS Boot from USB" in 6. Login using root for both the login ID and password. Order No.:

16 Intel IoT Gateway Connect and Test the Temperature Sensor 7.0 Connect and Test the Temperature Sensor 1. Connect the temperature sensor to your Gateway. Connect the Phidgets temperature sensor to port 6 of the Phidgets 1018 Interface Kit. Connect the Phidgets 1018 Interface Kit plugged into any USB port on your Gateway. 2. Execute the pytemp.py application on your Gateway: python /root/examples/pytemp.py 3. This application will read the temperature from the Phidgets Temperature sensor each second. The output to your screen displays the temperature and the time at which the temperature was recorded, similar to this: 16 Order No.:

17 Connect and Test the Temperature Sensor Intel IoT Gateway This content is also written to a local text file named phidgets_temeprature_data.txt Order No.:

18 Intel IoT Gateway Conclusion 8.0 Conclusion In this guide, you accomplished these tasks: Created a custom Wind River Linux 7 Gateway operating system image that included Phidgets packages and a Python application. Install this image onto your Gateway using a USB flash drive. Connected a Phidgets temperature sensor to the Gateway. Ran an example Python application to obtain temperature data from the temperature sensor. Continue to the next section for further development suggestions. 18 Order No.:

19 Development Suggestions Intel IoT Gateway 9.0 Development Suggestions Try these ideas to enhance your development: Create an application that uses other Phidgets sensors. For Phidgets source code examples that use Python, see: Python.zip Modify the example application so that it uploads the data to an online database. Use Python to publish data over MQTT from an Intel IoT Gateway. For help, see Intel IoT Gateway: Publishing Data to an MQTT Broker Using Python Getting Started Guide at Use Python to publish data to an external cloud service from an Intel IoT Gateway. Order No.: