Hi,
I'm opening this as an issue, because I have no idea how to send a message to you :p Feel free to close right away!
As I mentioned in the Nodemcu firmware repo, I'm working on an alternate approach to control somfy rollers. In my case, I installed outdoor aluminum rollers on all window in my house for security reasons, due to several robberies in the area. The motors are manufactured by the same factory as for somfy, but the receivers and hand controllers are another brand, and use the standard 433.92MHz band.
I thought to control the rollers from my phone, probably along the same lines as you are thinking. Therefore, I started looking into the 433MHz communication, looking to hack a controller, or maybe get a transmitter or something, but then after further thought I dropped the idea very early on.
You said that your approach would have the same security as the somfy controllers, and that is exactly what got me worried. My understanding (and please correct me if I'm wrong) is that there is virtually no security. Anyone with a 433MHz receiver could listen to the commands sent by your transmitters (either a hand controller or transmitter attached to an ESP), and then mimic the same train of pulses. In my case, it means that with less than USD$10 worth of hardware, and minimal software, that person could open all the rollers that I just installed in my house!
So, I figured that the 433MHz receivers and hand controllers have to be replaced.
Here's my approach:
Use the ESP with a tiny webserver onboard to pulse one of two gpio outputs for a predefined length of time. Each of those gpio outputs is connected to a relay big enough to drive a motor direction line. The length of the pulse is programmable, to allow different settings for the different rollers (different heights of the windows).
For an initial approach, what I intend is to connect the ESP relays in parallel with the 433MHz receiver relays, so that either can activate the motor directions. Yes, there is the danger that if one of the two is activating the roller in one direction, the other could activate it in the opposite direction, which could potentially damage the motor, but this is just for testing purposes. Once I figure all is working as intended, I intend to drop the 433MHz receivers.
Of course, my approach is intrusive: I have to go and open up the rollers and mess with the cables to install the ESP. Also, it requires one ESP per roller. In my case that's 23. But once done, the house is protected at minimum by the security of my wifi (wpa2), which is pretty good, and with some networking knowledge that could be vastly improved.
Anyways, I just thought to tell you about this :)