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Sampling ADC value from pixhawk

(Johns) #1

I am planning to interface sonar with ROV, which will be connected to pixhawk ADC pin (3.3 V). I am using hardware similar to BlueROV (raspberry pi and pixhawk). It requires high sampling rate too (800K).

Some of the resource I could find were related to Airspeed sensor adc interface.

I couldn’t find more resources over the internet. Require suggestion on the best possible way to read/sample ADC value from pixhawk?

(Rusty) #2

Hi @johnstmathai,

Thanks for the post. What type of sonar are you using? I’m not sure the Pixhawk will be suitable if it requires very fast sampling rate or collection of a lot of data.

@jwalser may be able to help with the ADC measurement info.


(Jacob) #3

Hi @johnstmathai, The pixhawk autopilot sofware runs on top of an RTOS. This type of sampling poses a few issues:

1: It will be hard, if not impossible to squeeze this rate of sampling out of the RTOS.
2: This rate of sampling will produce a relatively huge amount of data (12.8 Mbit) that will need to be processed and/or transferred.
3: The amount of time spent dealing with this data will interfere with the critical timing of the rest of the real-time program.

I recommend you use an independent processor to handle the sonar data.


(Johns) #4

@jwalser @rjehangir

Thanks for the quick reply. We might not go with the ADC sampling directly, instead will go with an intermediate processor and read data using Serial or Ethernet Interface.