# Interfacing with Gazebo during SITL

**URL:** <https://discuss.px4.io/t/interfacing-with-gazebo-during-sitl/17181>\
**Category:** ROS 1 / ROS 2\
**Created:** [June 15, 2020, 2:50pm UTC](https://discuss.px4.io/t/interfacing-with-gazebo-during-sitl/17181 "2020-06-15T14:50:48Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![pxflyer](https://discuss.px4.io/letter_avatar_proxy/v4/letter/p/839c29/32.png) [@pxflyer](https://discuss.px4.io/u/pxflyer)\
**Post date:** [June 15, 2020, 2:50pm UTC](https://discuss.px4.io/t/interfacing-with-gazebo-during-sitl/17181/1 "2020-06-15T14:50:48Z")

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Hi there.

I’m looking to send my own sensor readings to the PX4 during SITL. I thought I could use the “Simulator MAVLink API” by sending MAVLink messages such as HIL\_SENSOR, HIL\_OPTICAL\_FLOW, HIL\_GPS, etc. to TCP port 4560 but it doesn’t appear to be working. Is there another way to send raw sensor values to PX4 during SITL? This is for a research project.

This is what I’m referencing: [https://dev.px4.io/master/en/simulation/#simulator-mavlink-api](https://dev.px4.io/master/en/simulation/#simulator-mavlink-api)

Thanks!