Motorized Window Blinds – Phase 2

April, 2014

After the successful completion of motorizing a pair of Roman Shades (Phase 1), I began to research options for motorizing the shades in the rest of the house.  The majority of the shades in my home are Hunter Douglas Silhouette blinds, and I also have some wooden blinds.  Due to the high cost of replacing the Roman Shades, I wanted to go with a retro-fit option this time.  I read online that Somfy makes some motors that can be retro-fit into HD blinds to motorize them, but I had concerns that they might not fit.  Then I came across these excellent step-by-step instructions from a company called Automated Shade Inc. that guided me through the process.  These instructions gave me the confidence to give it a try.

In this phase (Phase 2), I did a 3 sub-projects:

A.  Pilot for a Hunter Douglas Silhouette blind

B.  Motorized a pair of wooden shades

C.  Completed the retro-fit of 5 other HD Silhouette shades

A.  Hunter Douglas Retro-fit

My first investment was in a single motor for driving a HD Silhouette roller shade.  My thinking was to try it as a “pilot” and confirm it will meet my needs before making a larger investment.  I purchased:

  • Somfy 1001683 LT 30 motor
  • Somfy 9013489 LT30 Crown & Drive Kit for Silhouette 2″ & 3″ Vane and Nantucket
  • Somfy 9014020 12V re-loadable battery tube + clips
  • 8 pack AA batteries
  • Somfy 1810493 RTS Dry Contact Single Channel controller (instead of a hand-held remote control)

Following the instructions, I was able to complete the retro-fit of the motor in the blind in less than 30 minutes.  Removing the shade from the window, was quite easy after watching this nice instructional video.  Unfortunately, the Crown & Drive kit was missing some crucial screws for securing the motor to the end-cap.  A quick email to the company I bought from indicated that these were #4 x 3/8″ pan head screws.  I purchased them locally and was back in business.

The blind fit perfectly back in the window, and I began the tedious process of using the controller to set the limits and intermediate stop-point for the window.  I suspect I was referring to some older documentation because it was not working.  In frustration, I went back to the Internet and found this helpful video from Somfy which provided the proper instructions that worked for me.  My initial impressions at this time was that it had similar speed as the Hunter Douglas PowerRise, but was a bit louder.  Being able to set intermediate stop points was a major benefit, which almost makes me want to buy one for the HD PowerRise.  I was, however, disappointed that I couldn’t find a way to hide the re-loadable battery tube, so I had to settle for mounting on the side of the window which makes it visible.

Next, I went to work integrating the RTS Dry Contact controller with the app I wrote to automate the Roman Shades.  I carefully considered buying the Somfy Universal RTS interface II (16 Channel), but it is SOOOO expensive!  My design only called for the need of 3 channels, and simple math indicated I could buy 3 single channel controllers for less than the 16 Channel interface.  That did, however, mean that I’d need to build my own interface to the PC for the Dry Contact controller.  For this, I used a new Arduino Ethernet board.  My main reason for choosing this board was to reduce the footprint of the interface.  I know I could have bought an Arduino Uno and an Enternet shield, but I also needed to stack a prototype shield on top and that wouldn’t fit well inside of a standard case.  The Arduino Ethernet shield proved easy to work with, although I didn’t realize that it offered only a 6 pin FTDI interface option for uploading sketches (instead of a USB port).  Luckily I already had an FTDI Basic board from Sparkfun, so it was not an issue.

I built a simple prototype shield with 3 reed relays for controlling the 3 buttons on the RTS Dry Contact Controller.  Even thought I had bad experiences with Mender reed relays on my last project, they were the only ones I had left, so I tested them all carefully before soldering them to the prototype shield.  I built a 4 pin custom cable using breakaway headers to allow easy disconnect of the RTS Dry Contact controller if needed.  Everything fit well inside a standard Arduino Project Enclosure, after some minor modification.

I drafted a quick sketch to provide a static IP address server to be accessed via sockets on port 8888 using a basic protocol that was extensible so I could add other controllers in the near future.  I updated the WDBlindControl app to include some logic to access the Arduino-interfaced RTS Dry Contact Controller and I was good to go.  I also augmented the HTML5 interface to work with the new blind.  Now, the Roman Shades and the single blind in my Living Room were under the control of the home automation system with the following logic:

  • At dawn, raise the blinds to let in light
  • At dusk, lower the blinds to provide privacy
  • If the room gets too warm, close the blinds to provide some shade
  • When the room returns to a target temperature, open the blinds again to let light in.
  • When the house is unoccupied, lower the blinds for privacy

B.  Wood Blind motorization

A few weeks alter, I came across another great video that provided step-by-step instructions for motorizing a set of wood blinds.  All I really wanted to do was adjust the slats to open and close – I didn’t need to automate the raise/lower of these shades.  This video explained everything and really helped me feel confident that I could do it on my own.  So, I purchased:

  • Somfy WireFree RTS Tilt Motor for 2″ Blinds #1000678
  • High Profile Case #9014529
  • Somfy 9014020 12V reloadable battery tube + clips
  • 8 pack AA batteries
  • Somfy 1810493 RTS Dry Contact Single Channel controller (instead of a hand-held remote control)

I was able to install these motors in a pair of wooden shades within an hour – very straighforward thanks to the great instructional video.  I trained the motor stop limits using the second channel RTS Dry Contact controller and everything was working well.

My quick build of the Arduino prototype shield with Reed Relays was not well planned for extensibility, so I started over with a new prototype shield and after a lot of planning was able to fit enough reed relays onto the shield to allow control for 3 separate channels (3 buttons each).  This time, I went with some nice, small Hamlin reed relays which gave me no issues.  I tweaked the Arduino sketch to accommodate the additional relays and was ready to go.  Finally, I extended the features on the WDBlindControl software module to accommodate the new controller and wired it into the automation functions.

Here’s where I hit a snag:  When using the RTS Dry Contact controller within the room, everything works fine.  However, when I place the controller on the Arduino on the 4-post rack in the basement, the signal only reaches one of the 2 blinds.  It seems to be a range issue caused by a massive metal I-Beam directly in between the controller and the blinds.  After some research, I concluded that I would need a Somfy RTS Repeater (1810791) which are not cheap.

C.  Taking the Plunge

There have only been a few times that my home automation hobby has required me to spend a significant sum of money at one time (> $1000) since I mainly build things myself.  However, this was one of the cases where a large investment would be required to complete the project.  Having convinced myself that the Somfy motors would work well to control my HD blinds, it was time to take the plunge and make an investment.  So, I purchased enough parts to motorize an additional 5 window blinds.  I saved a bit of money by finding some good deals on eBay, but most of my purchases were done from Automated Shades Inc. who appear to have some of the best prices I could find and provide excellent customer service.

Having already completed the retro-fit of one HD blind with the Somfy motors, I was able to complete the remaining 5 window shades.  After about 2 hours, all 5 blinds were motorized.  This time, my supplier remembered to include the screws that were missing from the last attempt, so there were no surprises.  I quickly added the third RTS Dry Contact controller to the Arduino (it looks ugly, but functions well), and extended all the software to work with the new blinds.

At this point, I’ve now got a total of 10 window shaded motorized including:

– 2 Roman Shades

– 2 Wood Blinds

– 6 HD Silhouette blinds

They are in 4 rooms of the house, and I have 1 channel control each room.  I know I could have good another way and had individual controllers for each blind, but I was unable to think of a time when this would be required. Also, sending a single signal that controls more than one blind means the house can be more responsive to automation request, rather than waiting for 10 separate signals to be sent serially.

Along with this purchase, I also made the investment in the RTS Repeater.  I figured that it would not only fix my issue with the wood blinds, but also benefit all of the Somfy motor controls by providing a stronger signal.  Unfortunately, this device has not solved my problem.  In fact, it has created a new problem.  When I plug in the repeater, I am getting very strange behavior – the blinds receive a signal but only move very slightly, and not to the presets that I set up. When I remove the repeater, it reverts back to normal operation. The repeater is not impacting the LT30 motors – they are all working fine with the repeater.  I have an open ticket with Somfy tech support and will hopefully be getting a resolution shortly.

April 14 Update:

I received this email from Somfy Tech Support regarding my problem with the RTS Repeater and the Somfy RTS Tilt motors for 2″ blinds:

The design of the tilt motor does not lend itself to workings well with the repeater. Essentially the repeater just resends the initial RTS signal to the motor, which is good in the case of a regular RTS motor such as the lt30. However due to the built in tilt functionality of the tilt motor i.e; if you hold the button you can fine adjust the motor, when the RTS repeater send the additional signal it actually is sending a stop command. This can be a little confusing as this phenomenon doesn’t affect any of the other RTS motors. I would suggest trying to reposition the antennas on the tilt motors and  make sure they are not tucked into the headrail. Unfortunately there aren’t any additional solutions we have to resolve the issue.

Disappointing!  Now, I’m back to square 1.  I’m going to try to extend the antenna on the RTS Dry Contact Controller to resolve my range issue.

April 16 Update:

The good folks at Automated Blinds Inc. were kind enough to let me return the RTS Repeater for a refund.  Now, how to fix the range issue?

After a bit of testing, I discovered that soldering a 9 inch long piece of wire into the through-hole at the tip of the PCB antenna on the RTS Dry Contact Controller solved my problem.  Yes, there is actually a pre-punched hole on the PCB almost as if the manufacturer wanted me to add a wire there to extend the antenna!  It took some trial-and-error to determine that a straight vertical orientation provided the best results.

Coming Soon:  Phase 3

I’ve been meeting with contractors to have them install some motorized blinds onto some arched windows in my Great room.

Arduino Uno Source Code


This video shows the use of the HTML 5 interface to control 4 Silhouette blinds in my living room simultaneously.  I demonstrate the control using a tablet and a smart phone to highlight the versatility of the HTML5 interface.



Initial testing of the new prototype shield and an RTS Dry Contact Controler


A close-up view of the prototype shield with 3 sets of reed-relays to control 3 RTS controllers  3 sets of wires using break-away headers used for quick disconnect of the controllers.


Uploading the sketch with 2 controllers


Final version with all 3 controllers attached and wired.  I used a nylon stand-off and a pan head screw to secure them on top and keep them separate to avoid interference.


A view of the WDBlindControl software interface that runs the automation and also allows manual override.



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