# Cannot arm or control a navigator-based ROV via pymavlink

**URL:** <https://discuss.bluerobotics.com/t/cannot-arm-or-control-a-navigator-based-rov-via-pymavlink/20829>\
**Category:** Blue Robotics Software\
**Tags:** pymavlink, navigator, ros\
**Created:** [July 2, 2025, 6:01pm UTC](https://discuss.bluerobotics.com/t/cannot-arm-or-control-a-navigator-based-rov-via-pymavlink/20829 "2025-07-02T18:01:15Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![EliotBR](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/eliotbr/32/6937_2.png) [@EliotBR](https://discuss.bluerobotics.com/u/EliotBR)\
**Post date:** [July 6, 2025, 8:44pm UTC](https://discuss.bluerobotics.com/t/cannot-arm-or-control-a-navigator-based-rov-via-pymavlink/20829/2 "2025-07-06T20:44:10Z")

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Hi @adnan, welcome to the forum! 🙂

Thanks for sharing what you’ve tried so far, and how it’s not working as expected.

Can you try [specifically waiting for a vehicle heartbeat](https://discuss.bluerobotics.com/t/controlling-pwm-values-with-python/12529/5)?

Waiting for a generic one means it’s possible to connect to some other component (e.g. the BlueOS camera manager), which could explain why your vehicle commands aren’t working properly.

> [@adnan](#):
>
> ```python
> # I did not use this thread initially, 
> # GPT suggested that continuous heartbeat sending is necessary. 
> # So I gave it a try. But no luck!
> threading.Thread(target=send_heartbeat, daemon=True).start()
> 
> ```

> [@Sending and recieving heartbeats to BlueROV from surface computer using pymavlink](https://discuss.bluerobotics.com/t/sending-and-recieving-heartbeats-to-bluerov-from-surface-computer-using-pymavlink/10940/6):
>
> I would note that while having the heartbeat in a separate thread can definitely be convenient, [it’s not recommended as the default approach](https://mavlink.io/en/mavgen_python/#:~:text=Generally%20it%20should%20be%20sent%20from%20the%20same%20thread%20as%20all%20other%20messages%20(to%20ensure%20that%20the%20heartbeat%20is%20only%20published%20when%20the%20thread%20is%20healthy).) in the mavlink docs …

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