$5.10 Arduino. Gearbest.com

Sounds like you use to sell them. I use to design and prototype them. Many issues with rf interference, mechanical failures and battery corrosion pr problems.

I have motion detectors all throughout my house. Planning to tackle motorized window blinds next.

Around $6.00 on Gearbest.com

Sure can.You could also use one raspberry to control several shades. Use power over Ethernet to reduce required wiring.

I use to work for one of those companies.

Plenty of torque. You could also use counterbalances.