# Collision Prevention

Source: https://forum.modalai.com/topic/2671/collision-prevention
Category: Development Drones (https://forum.modalai.com/category/44/development-drones)
Tags: starling
Posted: 2023-09-20 09:07:09 UTC by Caio Licínio Vasconcelos Pantarotto
Replies: 1 · Views: 1008

## Caio Licínio Vasconcelos Pantarotto · 2023-09-20 09:07:09 UTC

I've been following this tutorial to set the Collision Prevention on my starling: https://docs.modalai.com/voxl-vision-px4-collision-prevention-0_9/.

I have my VOA working.. I can see the VOA PC on the Portal and also on the debugger.. en_voa is set to true with DOF input, but when I try to fly in position mode, the drone is not avoiding collision. 

In the tutorial it is said to set : CP_DIST: 1.5
CP_DELAY: 0.0
CP_GUIDE_ANG: 0.0
CP_GO_NO_DATA: 1 .. I don't know in which config file I should set that.. I understand that voxl-vision-px4.conf changed to voxl-vision-hub.conf, but I don't see those parameters there.. So even though the VOA is generating data, it seems that PX4 is not receiving, or if it is receiving is not doing anything with it. If I try to set those parapets on QgroundControl it fails to write.. .futhermore I was trying to debug that using px4-listener.. to see what king of info from VOA it is receiving (idk if that is the real use of this service), but I didn't find any documentation for the px4-listener.. on the docs I just see it being used to check for GPS signal.

## Reply by Caio Licínio Vasconcelos Pantarotto · 2023-09-20 12:38:52 UTC

If I search for the word collision I get this files.. and indeed the .params hold those variables... Why is there different versions also ?

![Screenshot 2023-09-20 at 14.36.46.png](https://forum.modalai.com/assets/uploads/files/1695213476613-screenshot-2023-09-20-at-14.36.46.png)