Geko did a great Wifi integration (that does not need the Zwave Usnap). It was ero4444-proof. I applied it to my CT80 but it is made for your 3M-50.
It helps if you already have the 3M-50 talking on your LAN (that’s a bi-- uh bear), which is probably easier if you have an iPhone / iPad to setup the Tstat.
Please note, Radio Thermostat moved to a new Github repository:
you edit the standard “RRsThermostat” to be a “Radio Thermostat”
ok maybe not just copy-paste. But adaptation is not necessary.
Forgot to mention, the best part about the Wifi integration is, you have to don’t break the also-pretty-good OEM portal/remote and smartapp access to your Tstat.
And they recently upgraded the remote access (to compete better with Ecobee3 I suspect). They added “radar range” (something like that) to implement geopresence setting (tho I don’t use it), and an EXCELLENT daily history graph showing temperature, runtime and lost-comm-time. Some of these features were attempted as subscription add-ons but they must have given that up because it is freakin’ sweet and free now. Which is good because the physical interface to my CT80 is a dot-matrix dog, I hate touching it.