This command set was used to talk the payload from the ground during its flight. This system provided a huge amount of flexibility and let us maintain manual control, when required, of almost every aspect of the payload’s functions.
Over the Air Command Protocol and Listings
- All COMMAND strings begin with “SGS” and are all in capitals.
- All response strings begin with “SGSBalloon: ” and cannot be more than 2/3 lines long. “df -h” prompts about the longest response you can get away with.
- Format is: SGS<cmd> [<pwd>] <args>
Where <cmd> is a command from the list below
<pwd> is the OTA command protocol password
<args> is any optional arguments the command takes
- In the examples, the password is represented by 
- The system will ONLY accept commands from a certain call sign (M6TWO) but from ANY SSID. This allows some method of authentication whilst allowing more than one station to control the flight computer.
For example, both M6TWO -3 and M6TWO -6 are permitted to control.
|Command||Example Command||Example Response||Notes|
|SGSHELLO||SGSHELLO ||SGSBalloon: Hello from the SGS Weather Balloon!||A ping. The balloon will send back a hello string.|
|SGSECHO <text>||SGSECHO  hello||SGSBalloon: You said: SGSECHO hello||The balloon will echo <text>.|
|SGSDAEMONS||SGSDAEMONS ||SGSBalloon: [SNIP] /usr/bin/perl ./ax25perld.pl||The balloon will respond with ps listings from ax25perld and avionicsd.|
|SGSEXEC <command>||SGSEXEC  df -h||SGSBalloon: Filesystem Size [SNIP]||Warning: Dangerous command! The balloon executes the command, and responds with the shell response. Must not be a long response, 3 lines is about the max.|
|SGSPICTURE||SGSPICTURE ||SGSBalloon: Touched /root/etc/takepic||Touches the file /root/etc/takepic which flightc.pl looks for. When found, flightj.pl will send a “TAKE PICTURE NOW” command to the PICAXE.|
|SGSGREP <string>||SGSGREP  avionics||SGSBalloon: [SNIP] perl /root/avionicsd.pl||Returns the “ps ajx” grep’d listing for <string>.|
|SGSCUTDOWN <auth>||SGSCUTDOWN  DRaPh78r||SGSBalloon: Touched /root/etc/cutdown||Warning: Dangerous command! Touches the file /root/etc/cutdown which flightc.pl looks for. When found, flightj.pl will send a “CUT DOWN NOW” command to the PICAXE.|
|SGSKILLALL <auth>||SGSKILLALL  J74TfLp0||SGSBalloon: Starting kill…||Warning: Dangerous command! This command kills avionicsd, ax25perld, flightc.pl, flightj.pl and hard resets the PICAXE. The two Perl daemons rely on launcher/cron to restart. ONLY use as a last resort.|
|SGSTEST||SGSTEST ||SGSBalloon: PIC Response: [SNIP] SGSBalloon: GPS Response: [SNIP]||Pings the PIC to make sure it’s awake and ready. PIC has 5 seconds to respond. Grabs a bunch of GPS data to make sure it’s online and talking to gpsd. Returns results.|
|SGSCYCLE||SGSCYCLE ||Cycles the GPS and PIC using the hardware power control systems.|
|SGSSHUTDOWN||SGSSHUTDOWN  <auth>||Warning: Dangerous command! Shuts down the flight computer.|