NAVIO2 GPIO to Ardupilot Question

I am trying to incorporate a basic echo/trig based Ultrasonic sensor (HC-SR04) with my navio 2. I want to take this input and be able to view it in Mission Planner.

The way I understand the GPIO system working for Navio2 is either via the GPIO 17 & 18 pins on the UART. Or by setting servo rail pins to be GPIO.

I am currently trying to use GPIO 17 and 18 with no success. I have been setting “RNGFND1_PIN” = 18 and “RNGFND1_STOP_PIN”=17 in Mission Planner.

My logic voltage is 3.3 and I know the sensor works. Arducopter version 4.6.0beta1.

Any help / guidance for this would be great.

emlidtool test results

Hi Dylan,

Can you send me photos of your setup?