pyrtlsdr 0.2.7

pyrtlsdr
========

A Python wrapper for librtlsdr (a driver for Realtek RTL2832U based
SDR's)

|Build Status|\ |Coverage Status|

Description
===========

pyrtlsdr is a simple Python interface to devices supported by the
RTL-SDR project, which turns certain USB DVB-T dongles employing the
Realtek RTL2832U chipset into low-cost, general purpose software-defined
radio receivers. It wraps many of the functions in the `librtlsdr
library <https://github.com/librtlsdr/librtlsdr>`__
(`download <https://github.com/librtlsdr/librtlsdr/releases>`__)
including asynchronous read support and also provides a more Pythonic
API.

Usage
=====

pyrtlsdr can be installed by downloading the source files and running
``python setup.py install``, or using
`pip <http://www.pip-installer.org/en/latest/>`__ and
``pip install pyrtlsdr``.

All functions in librtlsdr are accessible via librtlsdr.py and a
Pythonic interface is available in rtlsdr.py (recommended). Some
documentation can be found in docstrings in the latter file.

Examples
--------

Simple way to read and print some samples:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code:: python

from rtlsdr import RtlSdr

sdr = RtlSdr()

# configure device
sdr.sample_rate = 2.048e6 # Hz
sdr.center_freq = 70e6 # Hz
sdr.freq_correction = 60 # PPM
sdr.gain = 'auto'

print(sdr.read_samples(512))

Plotting the PSD with matplotlib:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code:: python

from pylab import *
from rtlsdr import *

sdr = RtlSdr()

# configure device
sdr.sample_rate = 2.4e6
sdr.center_freq = 95e6
sdr.gain = 4

samples = sdr.read_samples(256*1024)

# use matplotlib to estimate and plot the PSD
psd(samples, NFFT=1024, Fs=sdr.sample_rate/1e6, Fc=sdr.center_freq/1e6)
xlabel('Frequency (MHz)')
ylabel('Relative power (dB)')

show()

Resulting Plot:
~~~~~~~~~~~~~~~

.. figure:: http://i.imgur.com/hFhg8.png
:alt: link

link
See the files 'demo\_waterfall.py' and 'test.py' for more examples.

Handling multiple devices:
--------------------------

*(added in v2.5.6)*

.. code:: python

from rtlsdr import RtlSdr

# Get a list of detected device serial numbers (str)
serial_numbers = RtlSdr.get_device_serial_addresses()

# Find the device index for a given serial number
device_index = RtlSdr.get_device_index_by_serial('00000001')

sdr = RtlSdr(device_index)


# Or pass the serial number directly:
sdr = RtlSdr(serial_number='00000001')

Note
~~~~

Most devices by default have the same serial number: '0000001'. This can
be set to a custom value by using the
`rtl\_eeprom <http://manpages.ubuntu.com/manpages/trusty/man1/rtl_eeprom.1.html>`__
utility packaged with ``librtlsdr``.

Experimental features
=====================

Two new submodules are available for testing: **rtlsdraio**, which adds
native Python 3 asynchronous support (asyncio module), and **rtlsdrtcp**
which adds a TCP server/client for accessing a device over the network.
See the respective modules in the rtlsdr folder for more details and
feel free to test and report any bugs!

rtlsdraio
---------

Note that the rtlsdraio module is automatically imported and adds
``stream()`` and ``stop()`` methods to the normal ``RtlSdr`` class. It
also requires the new ``async``/``await`` syntax introduced in Python
3.5+.

The syntax is basically:

.. code:: python

import asyncio
from rtlsdr import RtlSdr

async def streaming():
sdr = RtlSdr()

async for samples in sdr.stream():
# do something with samples
# ...

# to stop streaming:
await sdr.stop()

# done
sdr.close()

loop = asyncio.get_event_loop()
loop.run_until_complete(streaming())

rtlsdrtcp
---------

The ``RtlSdrTcpServer`` class is meant to be connected physically to an
SDR dongle and communicate with an instance of ``RtlSdrTcpClient``. The
client is intended to function as closely as possible to the base RtlSdr
class (as if it had a physical dongle attatched to it).

Both of these classes have the same arguments as the base ``RtlSdr``
class with the addition of ``hostname`` and ``port``:

.. code:: python

server = RtlSdrTcpServer(hostname='192.168.1.100', port=12345)
server.run_forever()
# Will listen for clients until Ctrl-C is pressed

.. code:: python

# On another machine (typically)
client = RtlSdrTcpClient(hostname='192.168.1.100', port=12345)
client.center_freq = 2e6
data = client.read_samples()

TCP Client Mode
---------------

On platforms where the ``librtlsdr`` library cannot be
installed/compiled, it is possible to import the ``RtlSdrTcpClient``
only by setting the environment variable ``"RTLSDR_CLIENT_MODE"`` to
``"true"``. If this is set, no other modules will be available.

*Feature added in v0.2.4*

Dependencies
============

- Windows/Linux/OSX
- Python 2.7.x/3.3+
- `librtlsdr <https://github.com/librtlsdr/librtlsdr/releases>`__
- **Optional**: NumPy (wraps samples in a more convenient form)

matplotlib is also useful for plotting data. The librtlsdr binaries
(rtlsdr.dll in Windows and librtlsdr.so in Linux) should be in the
pyrtlsdr directory, or a system path. Note that these binaries may have
additional dependencies.

Todo
====

There are a few remaining functions in librtlsdr that haven't been
wrapped yet. It's a simple process if there's an additional function you
need to add support for, and please send a pull request if you'd like to
share your changes.

Troubleshooting
===============

- Some operating systems (Linux, OS X) seem to result in libusb buffer
issues when performing small reads. Try reading 1024 (or higher
powers of two) samples at a time if you have problems.

- If you're having librtlsdr import errors:
- **Windows**: Make sure all the librtlsdr DLL files (librtlsdr.dll,
libusb-1.0.dll) are in your system path, or the same folder as this
README file. Also make sure you have all of *their* dependencies
(e.g. libgcc\_s\_dw2-1.dll or possibly the Visual Studio runtime
files). If rtl\_sdr.exe works, then you should be okay. Also note
that you can't mix the 64 bit version of Python with 32 bit builds of
librtlsdr, and vice versa.
- **Linux**: Make sure your LD\_LIBRARY\_PATH environment variable
contains the directory where the librtlsdr.so.0 library is located.
You can do this in a shell with (for example):
``export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib``. See
`here <https://github.com/roger-/pyrtlsdr/issues/7>`__ for more
details.

License
=======

All of the code contained here is licensed by the GNU General Public
License v3.

Credit
======

Credit to dbasden for his earlier wrapper
`python-librtlsdr <https://github.com/dbasden/python-librtlsdr>`__ and
all the contributers on GitHub.

Copyright (C) 2013 by Roger https://github.com/roger-

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