When our garage was rebuilt in 2017 a Chamberlain 8550WL belt-driven garage door opener was installed. We love how quiet it is, that it has a battery backup, and that it could be paired to a homebridge and operated with HomeKit, at least until September 2023 when Chamberlain closed access to third party plugins.

Enter Paul Whelan and ratgdo. Paul reverse engineered the encryption that Chamberlain has on these openers and made a board that has been open-sourced by others – for a good interview with Paul, check out this video. I bought Paul’s board, coded it with the ratgdo homebridge web installer, wired it to our Chamberlain garage door opener with an external power supply, and it worked flawlessly until I swapped out our Apple TV 4K for the latest Apple TV 4K that does Thread and Matter. Here’s an example of what the wiring looks like when the ratgdo is connected to the Chamberlain opener and here’s an example of pulling 3.3 volts from the 8550WL to power the ratgdo – I haven’t tried the latter, but likely will this spring/summer when it is warmer in the garage.

A few gotchas… Google Chrome or Microsoft Edge are required to transmit the ratgdo’s firmware to its board. Changing the user agent does nothing to help Safari communicate to the ratgdo through the web installer.