A Python wrapper for librtlsdr (a driver for Realtek RTL2832U based SDR’s)
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 including asynchronous read support and also provides a more Pythonic API.
pyrtlsdr can be installed by downloading the source files and running
python setup.py install, or using pip 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.
Simple way to read and print some samples:¶
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:¶
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) sdr.close() # 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()
See the files ‘demo_waterfall.py’ and ‘test.py’ for more examples.
Handling multiple devices:¶
(added in v2.5.6)
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')
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!
Note that the rtlsdraio module is automatically imported and adds
stop() methods to the normal
RtlSdr class. It also requires the new
await syntax introduced in Python 3.5+.
The syntax is basically:
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())
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
server = RtlSdrTcpServer(hostname='192.168.1.100', port=12345) server.run_forever() # Will listen for clients until Ctrl-C is pressed
# 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
"true". If this is set, no other modules will be available.
Feature added in v0.2.4
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.
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.
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 this issue for more details.
All of the code contained here is licensed by the GNU General Public License v3.