Rapid Curtain Actuator

It’s fast.

This Blynk-controlled curtain actuator can throw open these 9’ tall curtains in 1/2 a second. Since Blynk responds to http: get requests, I’ve also integrated it with Siri for voice commands. The stepper drives are disabled when it’s idle, so it’s easily backdrivable by hand. 10-turn pots are used as cheap encoders to keep it updated on its position. Microswitches are used at the end stops for its homing and potentiometer calibration routine.

And yes, there is a ‘slow’ mode for daily use.

 
 
 

Hardware

Continuous aluminum rod and printed grommet covers help lower friction and remove snags. I’ve also sewn a strip of fabric to keep the grommets from spreading out too far and biting into the rod. The ends of the curtains are pulled along with ball chain around 3D printed pulleys. The curtain rod holders are printed and air brushed with layers of Alclad lacquers to imitate metal. Acrylic panels had to be installed on the lower part of the window frames to protect the mini-blinds.

Electrical

  • Teensy 3.2 microcontroller

  • ESP-01 for WiFi

  • 5.0A dual-stack NEMA 23 stepper motors

  • DM556D stepper motor drivers

Software

  • TeensyStep library

  • Blynk library

  • All other code written as needed