I have a PX4FMU and PX4IO board running the Arducopter V2.9.1b Quad firmware. I am trying to add a Maxbotix XL-EZ4 sonar (http://www.maxbotix.com/Ultrasonic_Sensors/MB1240.htm).
The instructions here (http://copter.ardupilot.com/wiki/sonar/) say to connect the XL-EZ4's analog output to one of three pins on the PX4FMU+IO and set the SONAR_PIN parameter accordingly in Mission Planner.
However, I can't seem to find the SONAR_PIN parameter in Mission Planner (I see SONAR_ENABLE, SONAR_GAIN, and SONAR_TYPE).
Running the "sonar" test program from the command line interface constantly shows a measurement of 20cm, so the sonar is definitely not being read.
Am I missing something, or is there another way to set the sonar pin?
Thank you in advance!