# Autonomous Questions

**URL:** <https://forum.theavr.org/t/autonomous-questions/491>\
**Category:** AVR Drone Software\
**Created:** [April 25, 2023, 5:16pm UTC](https://forum.theavr.org/t/autonomous-questions/491 "2023-04-25T17:16:50Z")\
**Posts on this page:** 1\
**Showing post:** 3

<div class="post-metadata">

**Author:** ![nathan](https://yyz1.discourse-cdn.com/flex007/user_avatar/forum.theavr.org/nathan/32/4_2.png) [@nathan](https://forum.theavr.org/u/nathan)\
**Post date:** [April 26, 2023, 10:30pm UTC](https://forum.theavr.org/t/autonomous-questions/491/3 "2023-04-26T22:30:15Z")

</div>

Let me try my best to explain what’s going on.

While the ` __init__ ` method of the `MQTTModule` class (what you’re calling with `super(). __init__ ()`) connects to the MQTT broker, it does not start what is called the “event loop”. The event loop is an infinite loop that processes MQTT messages. This includes receiving incoming messages, and running callback functions defined in the `topic_map`, but at the same time, it also deals with sending messages as well. Without this event loop, nothing happens besides connecting to the broker.

In order to start the event loop, there are two options.

1. The `box.run()` method. This starts the infinite loop, and prevents any more code from ever running. This is ideal for when you want your sandbox code to always be responding to incoming messages, like the example I made.
2. The `box.run_non_blocking()` method. This starts the event loop in the _background_, and allows more code to run. This is great for when you have code that needs to run independently of incoming messages, like your code. This is how the software that gets data from the ZED Mini tracking camera works. When you do this however, you need to have some kind of infinite loop running, so your code doesn’t reach the end and stop executing.

Putting all of that together, this is how I would rewrite your example to work:

```python

import time

from bell.avr.mqtt.client import MQTTModule
from bell.avr.mqtt.payloads import AvrPcmSetBaseColorPayload
from loguru import logger

class Sandbox(MQTTModule):
    def __init__ (self) -> None:
        super(). __init__ ()
        logger.debug("Class initialized")

    def hello_world(self) -> None:
        logger.debug("Hello world")

        payload = AvrPcmSetBaseColorPayload(wrgb=(0, 100, 0, 0))
        self.send_message("avr/pcm/set_base_color", payload)

        logger.debug("Light changed")

if __name__ == " __main__":
    box = Sandbox()
    box.run_non_blocking()

    box.hello_world()

    while True:
        time.sleep(0.1)

```

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