Initially I had figured I'd make something that just runs a set of commands and then you would have to edit the source, recompile, etc. to get a different set of commands. Upon further review I decided this wouldn't be all that flexible and would generally be boring. So I wrote up a small command line app that takes commands directly from the standard input and sends them to the drone. Something like "takeoff" or "land" or "gaz .4". Today was the first day I was actually able to test the code and after a few minor changes it worked! I immediately found that I had the same issue with this code as we had had with nearly everything else we'd written for the Drone. We could do the usual takeoff and land and even adjust the Yaw and Gaz, but yet, as usual, we were unable to get the drone to move forward or backward. I dug into the AT command to make sure every bit of information was being sent correctly, and this seemed to be the case. Even other users in the community had used the same commands.
When developing the app I had figured I might run into this issue again, so I had written it so that a thread is immediately dispatched when the code is executed. This thread sends a simple AT command to the drone every 100ms or so, simply to keep the connection alive. In the past when we had looked at this issue before, Dave had found that with a constant "heartbeat" command, we were able to get Pitch and Roll working. Alas, this didn't seem to fix the issue in my case, or so I thought. So I had been sending a command that simply set the Yaw, Pitch, Gaz and Roll to their current settings. So the command had no visible effect on the drone but it did keep reminding it of its current status.
Upon further research I found that this issue had actually been come across by others and they had take a similar, yet slightly different, approach. They had used a heartbeat AT command but the command itself was different. Instead of setting those values mentioned, the simply trigger something called the "Watchdog", using AT*COMWDG=seq, where seq is the current sequence number.
At last, it worked! I was able to get the roll and pitch to change. I quickly realized that it wasn't sticking though and came to the conclusion that I should re-include the other heartbeat command I had used before, to constantly remind the Drone of its state. This fixed it and now the pitch and roll (and yaw and gaz...) stick!
One of the goals of this course was to get the Drone to perform a certain flight pattern on its own. Having to sit in front of the screen typing command after command was somewhat tedious and I thought I might develop a way for the program to read a file. The final scripting files are quite simple and are really the same as typing the commands, with each command one 1 line. I had some trouble getting this to work initially because I had forgotten about implementing a sort of "wait" functionality to pause between commands. Once that was up and running, though, I was able to write out some simple scripts to get the Drone moving.
Here are my sample scripts:
script1.ard:
takeoff
wait 7
land
script2.ard:
takeoff
wait 6
yaw .7
wait 5
yaw 0
wait 4
gaz .3
wait 7
gaz -.3
wait 4
pitch -.3
wait 2
pitch 0
land
script3.ard
takeoff
wait 7
pitch -.3
yaw .3
wait 2
land
These are simply text files and .ard was an extension I made up. I plan on testing this out further and will likely allow you to execute the program with a script as an argument instead of the current method of entering "file" then the script. Or maybe I'll keep both?
I'm also going to look into any startup scripts that the Drone has and look at the possibility of having the drone immediately run a set flight pattern when it starts.
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