Conceptualize MQTT<->ESP<->AVR Communication

[Xasin]

Since the ESP will be acting as a bridge between these different software levels, it is now important to come up with a fitting and "smooth" concept to handle data.

We could either:

• Be very server-heavy, and have ESP and AVR just be "slaves" to this setup, acting out on that received data.
• Be AVR-Heavy, letting that chip handle variable processing, and leaving the ESP as a simple translator between MQTT and the hardware-level side.
• Or be ESP-Heavy, with the ESP-Chip computing most of the data, sending important bits to MQTT and telling the AVR what to do.

Personally, I would go for the last option. It would give us the most processing power for that stuff (with floats, 32-bit processing power and more RAM), and since the communication between AVR and ESP will be so close and error-free, it would be easy to have the ESP "master" the AVR.

We also have to think about how to implement things like special effects, how damage is received, and especially: Shot Arbitration

I know it's a lot, but it would be nice to come up with a simple and hackable system that allows for easy expansion of everything :3

[Xasin]

After performing a short test on different pings, I've got pretty promising results!

Here's a graph depicting the Round-Trip ping time, measured by sending a Timestamp to the MQTT Network and recording its arrival time. The ESP was connected over my mobile-phone ((which had its mobile hotspot open), which connected via the internet to my local MQTT server.

As you can see, most pings are in the 250ms region, with only a few of them exceeding a second. This isn't perfect, but sufficient for most cases, as the lasertag-weapons will be capable of running fairly stand-alone.

A direct WiFi connect was, understandably, hard to beat. I got a constant ~20ms Round-Trip time for the ping. HOWEVER, at the same time the signal reach is very limited and would require us to set up a fairly large outdoor WiFi net to achieve similar coverage.

My vote is to use our phone's mobile hotspots. It's a bit slower but covers any area with normal broadband internet access.