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OpenSim allows you to simulate an OpenWSN network without physical devices.

How it works

A simulated network behaves exactly like a network with real hardware. You can interact with the OpenVisualizer, communicate with your nodes from the Internet. The difference is the firmware of each mote is running on your computer, rather than on a target device.

OpenSim does so by compiling the mote firmware as a Python extension module, and creating an instance of the resulting class for each emulated mote. When the simulation is running, these emulate motes communicate with the rest of the OpenVisualizer architecture (see Architecture) over the eventBus.

As illustrated in the diagram below, the emulated motes interact with the eventBus the exact say way a moteProbe instance (connected to a hardware mote) does.

The OpenVisualizer is not aware it is talking with emulated motes, and from a networking point of view, interacting with the emulated motes is exactly the same as interacting with real motes.

Preparing for a simulation

Directory organization

The OpenSim environment combines elements from the following repositories:

The OpenSim environment assumes that you have cloned them at the same level. That is, you need to have the openwsn-sw/ and openwsn-fw/ directories side-by-side on your computer.

Installation requirements

  • You need to be able to run the OpenVisualizer, so make sure installed the elements necessary for the OpenVisualizer to run.
  • Your computer needs to have gcc installed to be able to compile the firmware as a Python extension module. On Linux, that should be the case by default. On Windows, we recommend http://www.mingw.org/.
  • To be able to compile the firmware, the compiler will need to have access to the Python.h header file. If the compiler cannot find it, you will get the following error:

    File "/home/user/Desktop/openWSN-sim/openwsn-fw/SConscript", line 449, in sconscript_scanner
    scons: done reading SConscript files.
    scons: Building targets ...
    Compiling (shared) firmware/openos/projects/common/03oos_openwsn/03oos_openwsn_obj.os
    In file included from build/python_gcc/bsp/boards/board_obj.h:46:0,
                     from firmware/openos/projects/common/03oos_openwsn/03oos_openwsn_obj.c:15:
    build/python_gcc/bsp/boards/python/openwsnmodule_obj.h:11:20: fatal error: Python.h: No such file or directory
    compilation terminated.
    scons: *** [firmware/openos/projects/common/03oos_openwsn/03oos_openwsn_obj.os] Error 1
    scons: building terminated because of errors.

    The Python header files should be present by default on Windows. On Linux, you need to install the python-dev package:

    apt-get install python-dev
  • In some Linux installations, you might need to install the python-tk package:

    apt-get install python-tk

Compiling firmware

Before you can run a simulation, you need to compile the OpenWSN firmware as a Python extension module. For that, navigate to the openwsn-fw/ directory, and enter the following command:

scons board=python toolchain=gcc oos_openwsn

You can see an example output of this command on the OpenWSN builders:

This command creates the following Python extension module.

openwsn-fw/firmware/openos/projects/common/oos_openwsn.pyd

Running a simulation

Running a simulation is exactly like running the OpenVisualizer, but specifying that this is a simulation.

As with the OpenVisualizer, there are several interfaces available.

graphical user interface (GUI)

You have two options to start it:

  • from the command line, navigate to openwsn-sw/software/openvisualizer/bin/openVisualizerApp/ and enter the following command:

    python openVisualizerGui.py --sim [--simCount=<number of simulated nodes>]
  • enter the following command from openwsn-sw/software/openvisualizer/:

    scons rungui --sim [--simCount=<number of simulated nodes>]

Brackets are not required when issuing a command. For example, to run a 5 motes simulating network, use following command without brackets. It's the same for following two cases: CLI and Web interface

scons rungui --sim --simCount=5

command line interface (CLI)

You have two options to start it:

  • from the command line, navigate to openwsn-sw/software/openvisualizer/bin/openVisualizerApp/ and enter the following command:

    python openVisualizerCli.py --sim [--simCount=<number of simulated nodes>]
  • enter the following command from openwsn-sw/software/openvisualizer/:

    scons runcli --sim [--simCount=<number of simulated nodes>]

web interface

You have two options to start it:

  • from the command line, navigate to openwsn-sw/software/openvisualizer/bin/openVisualizerApp/ and enter the following command:

    python openVisualizerWeb.py --sim [--simCount=<number of simulated nodes>]
  • enter the following command from openwsn-sw/software/openvisualizer/:

    scons runweb --sim [--simCount=<number of simulated nodes>]
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4 Comments

  1. I don't really understand.

    About the "Running a simulation" topic, it's exactly about running OpenVisualizer, not running OpenSim.

    After reading this page, I have no idea to use OpenSim with OpenVisualizer.

  2. Joey Duh,

    The OpenVisualizer is able to gather the debugging information/packet on event bus injected by the hardware motes from serial port and show the debugging inforamtion of the motes.

    OpenSim, as part of OpenVisualizer is able to emulate a mote to generate data and inject to the event bus.

    If you use the command

    scons runweb

    OpenVisualizer will search the serial port connected to the computer to gather data.

    If you use the command 

    scons runweb --sim --simCount=3

    OpenVisualizer will create 3 threads to simulate 3 motes and generate the debugging data, rather from real hardware.

     

    Tengfei

  3. I have a problem. When using OpenSim, is time count is different than real hardware?

    Using simulation mode, i got DAO every 2 seconds. However, using real hardware i got DAO every 30 seconds.

    1. Chang, chun-wei yes, the simulation is an event-driver emulator. Once every events before sending DAO are down. the simulation will send DAO next immediately. When there are less motes in the network, simulation will run faster than real.