smart curtain or blinds closer

thingiverse

This is a "remix" (but really upgrade) of [thing:5322431](https://www.thingiverse.com/thing:5322431). It's ridiculous how expensive [these](https://us.switch-bot.com/products/switchbot-curtain) things are and I don't want something with batteries (I'm going to drill holes for the curtain rods anyways...) so I designed this motorized curtain closer that only needs the following : These 3D printed parts [1x beaded chain (~$1/ft, need ~width of curtains, or 4-6ft for blinds) (~$5-10)](https://www.ebay.com/itm/221319132229) [1x smart outlet ($8)](https://smile.amazon.com/dp/B08Y87WD1X) [1x 12v geared motor, 10rpm (~$5)](https://smile.amazon.com/dp/B07S2KWRWQ) [2x endstops (~$1)](https://smile.amazon.com/dp/B07MW2RPJY) [1x 12v wall wart (~$5 or free)](https://smile.amazon.com/dp/B0875WMYCX) [1x 5v standard USB charger (~$5 or free)](https://smile.amazon.com/dp/B07437M5QQ) [1x 5v dpdt relay (~$3)](https://smile.amazon.com/dp/B086LB8MD2) 10-20ft 20-22 awg wire (I like using ethernet because it's cheap and a good conductor, but you need so little I'm not going to even link to it. You might need more for curtains rather than blinds, but in that case I'd just use [an extender (~$10)](https://smile.amazon.com//dp/B081CTBVF5) So a total of 30-40 depending on if you have some scrap laying around The general workflow You install this at the top of your curtains, with the motor on one side and an idler on the other so there's a loop of beaded chain. Power (12v) is always applied to the circuit, turning the motor until an indicator on the beaded chain reaches a limit switch, Using a smart switch, you toggle power (5v usb) to the dual spdt relays, switching the polarity of power (12v) going to the motor, reversing its direction. Using a clever circuit you can circumvent the first limit switch, driving the chain in the opposite direction until it hits another limit switch. This means the curtains can only ever be fully open or closed. Following the flow of power 1. A 12v psu is plugged into the wall, and the output leads into the dual dpdt relay common terminal 2. A 5v usb adapter is plugged into the smart outlet. Use a usb to barrel cable + barrel pigtail or just cut and strip a usb cable and apply power to the dual spdt relay module's input 3. 12v is output from the SPDT relays up to the geared motor where all the printed parts and mechanical components are. 4. The default state of the relay causes power to be output with one polarity, and applying power (5v) to the relay module switches both paths, causing the polarity to reverse.