Took just a little digging to find the correct commands to get my Arduino + Adafruit GPS based “clock” to talk to gpsd on the Raspberry Pi (the Arduino is powered and connected to a USB port on the Raspberry Pi.) First, I did
sudo apt-get install gpsd
sudo apt-get install gpsd-clients
sudo dpkg-reconfigure gpsd
(using /dev/ttyACM0) when prompted and then
for the display below
Clock is running https://github.com/allendav/GPSClock code
Using CubicSDR, a rtl-sdr dongle and the tracking software I’m developing (and a nice Arrow II dual band yagi), I picked up the CW beacon for the recently launched XW-2E cubesat this morning (see the portion of the waterfall display circled in red
First, I used parts of this gist by floehopper to set up rtl-sdr utilities on the Raspberry Pi (already running Raspbian with a 8 GB flash card at its disposal):
pi@raspberrypi ~ $ sudo apt-get update
pi@raspberrypi ~ $ sudo apt-get upgrade
pi@raspberrypi ~ $ vi no-rtl.conf
pi@raspberrypi ~ $ sudo mv no-rtl.conf /etc/modprobe.d/
pi@raspberrypi ~ $ sudo apt-get install git-core
pi@raspberrypi ~ $ sudo apt-get install git
pi@raspberrypi ~ $ sudo apt-get install cmake
pi@raspberrypi ~ $ sudo apt-get install libusb-1.0-0-dev
pi@raspberrypi ~ $ sudo apt-get install build-essential
pi@raspberrypi ~ $ git clone git://git.osmocom.org/rtl-sdr.git
pi@raspberrypi ~ $ cd rtl-sdr/
pi@raspberrypi ~/rtl-sdr $ mkdir build
pi@raspberrypi ~/rtl-sdr $ cd build
pi@raspberrypi ~/rtl-sdr/build $ cmake ../ -DINSTALL_UDEV_RULES=ON
pi@raspberrypi ~/rtl-sdr/build $ make
pi@raspberrypi ~/rtl-sdr/build $ sudo make install
pi@raspberrypi ~/rtl-sdr/build $ sudo ldconfig
pi@raspberrypi ~/rtl-sdr/build $ cd ~
pi@raspberrypi ~ $ sudo cp ./rtl-sdr/rtl-sdr.rules /etc/udev/rules.d/
pi@raspberrypi ~ $ sudo reboot
Then, I added sox (to get the play command):
pi@raspberrypi ~ $ sudo apt-get install sox libsox-fmt-all
I hooked up a speaker to the Raspberry Pi audio port and then tuned and listened to Puget Sound’s favorite packet frequency:
rtl_fm -f 144390000 -M fm -s 12k - | play -r 12k -t s16 -L -c 1 -
Worked nicely. Need to add squelch argument and combine this with the demodulator I’ve been working on. Satellite tracking with automatic recording of space station packets is the ultimate goal.
New firmware (thanks steveis), recalibrated, fixed some incorrect settings in the transmitter too. Setup autolevel correctly this time. Still waiting for replacement arm. Soon.
After sitting (and running) on my desk in a breadboard for forever, the GPS and Arduino powered UTC clock is finally getting properly housed in a project box. Now just waiting on a couple connector blocks and some wire for the harness.
I’m making progress on the 440 MHz preamp kit. Should be up and running soon. Will make hearing the 70cm satellites a lot easier I hope. (The kit is by Ramsey, fancy aluminum case by Hammond.)
the demodulator you’ve been working on starts outputting meaningful data instead of gibberish (T7RPUR WIDE1 WIDE2 are valid packet radio strings).
I’m writing the demodulator in C++ and it uses the Goertzel algorithm. Need to continue to flesh out the framer, and hook up STDIN to accept sound from rtl_fm and my new SDR dongle.
The goal: automated reception of Space Station packet radio, powered by Raspberry Pi.