[Paparazzi-devel] Cannon Launch Detection

[David Bryant]

Hi,

I'm attempting to extend paparazzi to detect rapid acceleration launch 
from a cannon. The cannon is activated by a separate system. The 
aircraft is accelerated at approximately 24 g-force along a 3 metre 
barrel length.

I need to detect the launch within paparazzi immediately and am 
investigating an approach based on sampling the output from a ADXL321 
accelerometer on an ADC paparazzi input.

I was hoping to be able to create a function that was periodically 
invoked at say 200Hz and polled the accelerometer ADC input. The routine 
would process the data until some criteria had been met that indicated a 
launch. On detecting a launch the routine would do something (invoke a 
function?) that would allow cause flightplan to progress to the next 
stage. After this the routine would no longer need to be called.

I am currently going down the path of using the conf/modules mechanism 
to define my function and its periodicity, and writing the function.

Could someone please provide some general advice and any tips in regard 
to my approach or an alternative approach? I am having trouble finding 
any precedence or examples of this kind of thing. Can you draw my 
attention to a example that I should be looking at?

Thanks,
Dave