Hacking

I recently released FreeFall 800, open source firmware for the Gravity 800 smoker/grill from Masterbuilt. The project started because I needed to open the controller to fix a broken wire. That is when I noticed that inside was a standard ESP32 module, with a plainly visible programming header. This made me very surprised to find that there were little to no details online about the controller’s internals. In this post I aim to document everything I managed to reverse engineer about the Gravity 800 controller board, and will discuss some of the very strange choices the designers made.

Today I’m publicly releasing a project I’ve been working on for a while: FreeFall 800. FreeFall 800 is a local first, open source firmware project, that replaces the factory firmware that comes on the Masterbuilt Gravity 800 smoker grill.

A year ago I was in the market for a new grill, and ended up purchasing a Masterbuilt Gravity 800 charcoal smoker grill. The grill itself has been great. However, like most “smart” devices, it has one fatal flaw: Without the internet, manufacturer’s servers, and their mobile app, you cannot make use of any of the “smart” remote control or monitoring features.

This whole project started when I happened across the NASA Perseverance Raw Image Library one day. Something about the constantly varying combination of images: some with scientific purposes, some for navigation, and some of the rover itself, along with the fact that they were FROM MARS kept me coming back to the page to see what Curiosity had been up to lately. This eventually lead to the idea of having a digital picture frame which would cycle through the latest raw images from the Perseverance rover. So that’s what I set out to build.