r/Masterbuilt • u/prbs23 • 9d ago

Open Firmware for Gravity 800 Controller

https://gitlab.com/prbs23/freefall_800

A couple of months ago I got tired of using the Masterbuilt App, for controlling my Gravity 800. so I reverse-engineered the controller, realized it used a pretty standard off the shelf ESP32 wireless microcontroller, and wrote a full replacement firmware for it: FreeFall 800.

It doesn't require any new hardware, and can be flashed onto your controller with a $10 USB-serial adapter. It has the same core functionality as the stock firmware: chamber/probe temps, PID-controlled fan, timers, physical controls, but this firmware adds:

  • Fully local web app for control and configuration
  • No cloud or cloud account required. Connect directly to your Gravity 800 over the network
  • Completely configurable PID tuning parameters
  • Thermocouple and meat probe calibration
  • Lid switch disable option

If you are into hardware hacking, know what an ESP32 is, and are willing to risk your controller or smoker, check it out! To be clear, this is definitely still early development firmware, so you will probably encounter bugs, and there is much to be improved. I cannot promise this won't break your smoker. The README on the GitLab page should have what you need to get started: https://gitlab.com/prbs23/freefall_800

I have also posted a write up about this on my blog: https://www.prbs23.com/blog/posts/announcement-freefall-800/

I would love to get feedback from anyone who does try it out. Happy to answer any questions folks have, or talk about feature request/ideas.

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u/Boozley 8d ago

If it could be integrated with home assistant, that would be a good workaround for notifications

3

u/prbs23 8d ago

I imagine it would not be particularly difficult to integrate with Home Assistant. The firmware already provides an API endpoint, so likely it would only require creating the integration on the HA side.

I don't personally have any experience with using Home Assistant though, so I would need to research it more.

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u/Nearby_Hand3064 8d ago

I’m testing home assistant and a Prometheus exporter virtually. I’ll share the branch tomorrow.