This is the curtainator. It's designed to open curtains that use a rope loop on one end. I couldn't find any product like it so enjoy! I'll probably be making improvements to this as things break.

 

 

Components:

There are 3 main components of this print:

Wall Mount:

The wall mount was pretty specific to my setup. I wanted to reuse the drilled holes that the previous pulley used and I needed to get around a window sill. There's a slit in the bottom mount so the top mount can slide up and down to adjust the tension on the rope. This is kinda tricky to print so you'll probably want supports in there.

• bottom-wall-mount.stl
• top-wall-mount.stl

Gearbox:

The curtainator uses a 5:1 planetary gearbox to increase the torque of the stepper. Why a planetary gearbox? Because it looks super cool. I used 3 planets in my gearbox. The planetary gears turn a spur gear that is concave to hug the rope. It links up to another spur gear (which I'm calling the auxiliary gear) to “grab” the rope and keep it from slipping.

planetary gears:

• ring-gear.stl
• planet-gear.stl (x3)
• sun-gear.stl

rope spur gears (and related mounts):

• carrier-gear.stl
• carrier-shaft.stl (x3)
• carrier-arms.stl
• aux-gear.stl
• aux-gear-mount.stl
• aux-gear-shaft.stl

Bracket:

The bracket is what mounts to the stepper motor and keeps everything together. It uses 4 20mm M3 screws to combine the bottom bracket, ring gear, and top bracket into a fun curtainator sandwich. There's also a cap on the top that keeps the carrier gear centered.

• bracket-bottom.stl
• bracket-top.stl
• bracket-cap.stl

 

Printing:

I printed with prusament PLA and a 0.25 nozzle. Most things shouldn't need supports except for the bottom-wall-mount.stl and bracket-top.stl.

Non-3D printed components I used:

• A lot of M3 hex socket screws and nuts of varying lengths (6,8,12,16,20mm). The nuts should be hex, not square
• 5 608-2RS ball bearings 
• Nema 17 Stepper motor. Mine was 2A with 59Ncm of torque, but get whatever works
  • I also used an esp32 to control a TB6600 driver, but again get whatever works for you
  • You'll also need a power supply, I used a 24v 5A power supply

All the components above were found on Amazon.

 

Automation?:

You can do this however you want, but I'll share what I did. I use an esp32 with esphome to control the TB6600 driver. The code for esphome is below. Once esphome is flashed, I can use home asssistant to automate the curtains however I like. Currently I open/close for sunrise/sunset and also when I start watching my TV.

 

substitutions:
  deviceid: esp32_5
  esphomename: esp32-5 # underscore in hostname is discouraged
  devicename: Curtains
globals:

id: curtains_max
type: int
restore_value: no
initial_value: "56000"
id: curtains_mostly_open
type: int
restore_value: no
initial_value: "46000"

esphome:
  name: $esphomename
  platform: ESP32
  board: wemos_d1_mini32
  on_boot:
    priority: -100.0
    then:
      - stepper.report_position:
          id: curtains_stepper
          position: !lambda return id(curtains).position * id(curtains_max);
      - stepper.set_target:
          id: curtains_stepper
          target: !lambda return id(curtains).position * id(curtains_max);
      - sensor.template.publish:
          id: position_sensor
          state: !lambda return id(curtains_stepper).current_position;
wifi:
  ssid: !secret wifi_smart_ssid
  password: !secret wifi_password
  fast_connect: true
  domain: .home
Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: $deviceid
captive_portal:
api:
ota:
web_server:
  port: 80
Enable logging to ESPHome
logger:
Disable logging to serial
  baud_rate: 0
  level: debug
pins that connect the esp32 to the driver
stepper:

platform: a4988
id: curtains_stepper
step_pin: GPIO16
dir_pin: GPIO17
sleep_pin: 
  number: GPIO21
  inverted: true
max_speed: 5000 steps/s
acceleration: 5000 steps/s^2
deceleration: 5000 steps/s^2

report the position of the curtain (in steps) to home assistant for debugging
sensor:

platform: template
name: "Curtains Position"
id: position_sensor

pull in the status of the door sensor from home assistant
binary_sensor:

platform: homeassistant
name: "Curtain sensor"
entity_id: binary_sensor.lumi_lumi_sensor_magnet_aq2_on_off
id: curtain_sensor
filters:

invert:
internal: true
on_press:
  then:

stepper.report_position:
  id: curtains_stepper
  position: 0
stepper.set_target:
  id: curtains_stepper
  target: 0
cover.template.publish:
  id: curtains
  position: 0.0
sensor.template.publish:
  id: position_sensor
  state: !lambda return id(curtains_stepper).target_position;





cover:

platform: template
name: "Curtains"
id: curtains
device_class: curtain
has_position: true
open_action:
the first open command will only open partially, the second will open all the way

if: 
  condition:
  - lambda: return id(curtains_stepper).target_position >= id(curtains_mostly_open);

  then:
- stepper.set_target:
    id: curtains_stepper
    target: !lambda return id(curtains_max);
- sensor.template.publish:
    id: position_sensor
    state: !lambda return id(curtains_stepper).target_position;
if: 
  condition:
  - lambda: return id(curtains_stepper).target_position < id(curtains_mostly_open);

  then:
- stepper.set_target:
    id: curtains_stepper
    target: !lambda return id(curtains_mostly_open);
- sensor.template.publish:
    id: position_sensor
    state: !lambda return id(curtains_stepper).target_position;

close_action:

if:
  condition:
- binary_sensor.is_off: "curtain_sensor"

  then:
- stepper.set_target:
    id: curtains_stepper
    target: -1000

stop_action:

stepper.set_target:
  id: curtains_stepper
  target: !lambda return id(curtains_stepper).current_position;
sensor.template.publish:
id: position_sensor
state: !lambda return id(curtains_stepper).current_position;
cover.template.publish:
  id: curtains
  position: !lambda return (float)id(curtains_stepper).current_position / (float)id(curtains_max);
position_action:
stepper.set_target:
  id: curtains_stepper
  target: !lambda return pos * id(curtains_max);
sensor.template.publish:
  id: position_sensor
  state: !lambda return id(curtains_stepper).target_position;

if we only open the curtains partially, publish that
on_open:

if:
  condition:
- lambda: return id(curtains_stepper).target_position == id(curtains_mostly_open);

  then:
- cover.template.publish:
    id: curtains
    position: !lambda return (float)id(curtains_mostly_open) / (float)id(curtains_max);

optimistic: true
assumed_state: true