== Zynq-based WISER platform - Spectrum sensing with multiple nodes (OEDL) ==

[[TOC(Tutorials/k0SDR*)]]

=== Description ===
This tutorial demonstrates how to record spectrum on multiple nodes using an OEDL script.


=== Hardware / Software Resources utilized ===
 1. SB6 nodes with WISER platform.
 2. ''wiser_sb6_zedboard.ndz'': disk image loaded onto nodes.
 3. ''wiserd'' application - [http://wiser.orbit-lab.org/wiki/wiser Check here for more info].

=== Spectrum sensing with an OEDL script  ===
 * Follow the [wiki:Tutorials/k0SDR/Tutorial13 start-up instructions] to program and setup the FPGAs on both the nodes.
 * The following OEDL script resides on the console of SB6 and can be used to run spectrum sensing on both the nodes at once.
{{{
defProperty('radio',"zynq","")
defProperty('rx_freq1', "800e6", "")
defProperty('rx_freq2', "815e6", "")
defProperty('rx_gain', "10", "")
defProperty('rx_fft_bins',"256","")
defProperty('rx_fft_scaling',"170","")
defProperty('rx_fft_averaging',"256","")
defProperty('start_fft',"0","")
defProperty('time',10,"")

require './wiserd.rb'

#defGroup('receiver', "node1-1.sb6.orbit-lab.org, node1-2.sb6.orbit-lab.org" ) do |node|
defGroup('receiver', "node1-2.sb6.orbit-lab.org" ) do |node|
  node.addApplication("test:app:wiserd") do |app|
    app.setProperty('--radio',property.radio)
    if ((node).to_s.casecmp("node1-1.sb6.orbit-lab.org") == 0)
      app.setProperty('--zynq_rx_freq', property.rx_freq1)
    else
      app.setProperty('--zynq_rx_freq', property.rx_freq2)
    end

    app.setProperty('--zynq_rx_gain', property.rx_gain)
    app.setProperty('--zynq_fft_bins', property.rx_fft_bins)
    app.setProperty('--zynq_fft_scaling', property.rx_fft_scaling)
    app.setProperty('--zynq_avg_window', property.rx_fft_averaging)
    app.setProperty('--fft_engine',property.start_fft)
  end
end

onEvent(:ALL_UP_AND_INSTALLED) do |event|
  wait 5
  info "Starting the Receiver"
  group("receiver").startApplications
  wait 1
  property.start_fft = "1"
  wait property.time
  property.start_fft = "0"
  group("receiver").stopApplications
  Experiment.done
end 
}}}
* The script here takes the receive center frequencies and run time as parameters along with the number of fft bins etc. Run the script by typing
{{{
omf exec sys:exp:zynq_spec_sense.rb --time 20
}}}
* Run tcpdump on the nodes to see packets coming from the zedboard to the node
{{{
root@node1-2:~# tcpdump -i eth2
}}}
* FFT bin data is collected in /zynq_rx_fft.bin on each of the nodes. These files can be copied to the console and the spectrum can be plotted using an octave script.