I’ve got a bunch of home automation set up to control my lights, tv, and even my robot vacuum. I live in an apartment and rent so permanent modifications are an obvious no go. Modifications that are easy to reverse when I move out are my only option. Our blinds (the rolling style that just go up and down) are a bit of a pain because of where the cable is and also inconvenient to manually roll up and down all the time so I decided to make an electric blind opener/closer. We have three in the bedroom, but one is facing the balcony and always stays down, so I’m automating two.
My plans are to use a heavily geared down motor with an ESP8266 and motor controller to turn the string and make the blinds go up and down. A 30 rpm motor will take around 20 seconds to open/close according to my calculations. I’m going to use a magnetic reed switch to detect when the bottom of the blinds are all the way up at the top and a simple timer to know when they’re at the bottom. Unfortunately they move around way too much to be able to put a sensor at the bottom. I might come up with a different way of detecting when they hit the ground, but I assume a timed descent should work fine if it “homes” everytime it goes back up.
All of the parts have arrived so it’s time to start designing and building this thing. I’m going to 3D print a gear and plastic enclosure to sit the electronics and motor in. The enclosure will be mounted next to the cord loop and will be mounted so it has tension around the gear. I’m going to initially design it to run off a small LiPo battery to avoid having to run cables to it. This is a 3S (~12v) 2200mAh battery. Hopefully it will last a few months before needing a recharge.
It will use MQTT to plug into the rest of my home automation system but will also feature a button on it so you can control it locally (ie without needing mqtt etc to be working). This is important because the motor is so geared down it’s impossible to freely turn it. If the home automation system ever goes down I don’t want to have to take this off to open/close the blinds.