Buildings account for 20-40% of total energy use in developed countries. Window shades (or blinds) can help to reduce building energy use and improve visual comfort (i.e., reducing glare and increasing daylighting). A recent study showed that occupants are fairly inactive when operating manual roller shades (O’Brien et al. 2013) which could lead to increased visual discomfort and increased heating and cooling energy use. With aspirations to address issues associated with human inactivity I created an automatic motorized roller shade.

The motor moves the shade position depending on the of the location of the sun and the illuminance (i.e., amount of light) hitting a workplane (e.g., your office desk or kitchen table).

One of the best parts of this instructable is that you do not need to purchase a brand new roller shade to make this work. I will demonstrate how to retrofit an existing manual roller shade into an automatic motorized one using Arduino. The project used Arduino with the Adafruit motor shield to control the interaction between a stepper motor and a digital luminosity sensor.

This Instructable is structured:

  1. Introduction: What is 'good' shade position?
  2. Required supplies
  3. Assembly
  4. Code explanation
  5. Summary

Step 1: What Is 'good' Shade Position?

As the sun moves across the sky during the day, where should the shade be positioned? What if it is a very sunny day and there is too much light entering a space causing glare? What if it is an overcast day? This step tries to answer these questions by asking: What is 'good' shade position?

In general, we want the shade position to let in as much light as possible without cause any visual discomfort (i.e., maximize daylighting and minimize glare).

The picture above was taken sitting down at my office desk. It was an example of 'good' shade position because the shade was positioned so it was blocking direct sunlight yet was still allowing maximum diffuse sunlight to enter into my workspace.

Sunlight can be broken into essentially two components: direct and diffuse. The direct component comes straight from the sun whereas the diffuse component is created when a portion of direct sunlight scatters due to molecules in the atmosphere.

This project aims to control shade position to always block direct sunlight when present and maximize the diffuse component entering the workspace.

<p>Very cool idea to have blinds that follow the sun across the sky during the day. That would be something that I would love to have in my office. For the last part of the day no matter what I do the sun is all ways directly in my face. These blinds would definitely help with my sun problem. http://www.sunblindsandcurtains.com.au/internal-blinds</p>
<p>I think this is the most science oriented automatic blind implementation.</p><p>But what if its winter and you need sunlight to enter the building to heat it up?</p><p>During summer night you might want the blinds to be fully up so the building loses some of the heat absorbed during daytime, and close them right before the sunrise.</p><p>A thermal sensor might gave a complete solution to this, (with the necessary additions to the code)</p><p>Also a manual override would be handy.</p><p>Would these additions be possible in the code?</p>
<p>this is just too incredible...</p>
<p>Hey Nick!</p><p> Nice project - I'm doing something similar with my own (venetian) blinds. Instead of using a Luminosirty Sensor I'm using a cheap LDR sensor. Infact, &quot;cheap&quot; is one of my main concerns as I want to do all my windows. Right now my setup cost me roughly eight dollars per window (not including the motor - scavenged from an old printer) - it checks outdoor light levels, indoor temp and adjusts blinds according to predefined thresholds. It has a handy IR remote to override the blinds too! :) I'm currently testing the setup running on solar, but it has increased the costs significantly - roughly $20 for battery and panel. Anyway, would it be possible to take a peak at your code and see if I can borrow a few ideas from it? Looks like it works wonderfully! </p>
<p>Scroll down to bottom of Step 4 and you can download the code there. I hope it helps and good luck with your project.</p>
This article reads just like some robotics papers I've read, except it's even more clear. Good job!
Nicely done! Do you know: if you want the heat of the sun out by using blinds, the blinds should be reflective and outside of the building. with these black ones inside the room what will happen is this: the solar irradiation is absorbed by the black material and is then sent out from the blind in the form of infrared radiation, causing the room to heat up.
<p>You are right, the thermal aspects of blinds are also important but this was outside of this projects scope. An ideal placement for a window blind is actually outside the window (as opposed to inside the window in this project). This reduces the solar heat gain entering the room but there are design aspects that cause issues with placing blinds outside of windows (e.g., weather effects such as wind etc.).</p>
<p>I have always wanted to get a system like this up and running! I have tried on one occasion before but I could not find a motor that had enough torque that could lift my blinds. My blinds are about 7 foot long and using a baggage scales requires about 2-3kg of force to pull up from completely drawn. Any advice on the size/torque required? How did you figure out the torque needed?</p>
<p>I would suggest having a motor torque of 1.5 Nm based on really rough calculations. The motor I used had a torque of 3 Nm and could easily lift the roller shade. This spread sheet provided by Somfy could help in your calculations: (https://www.somfypro.com/documents/531668/3408119/<strong>Roller</strong>+<strong>Shade</strong>) Note: this link will download an excel spreadsheet.</p><p></p><p><strong><br></strong></p>
<p>This is a very impressive solution to natural lighting control . You have made a great project that I am sure will be utilized in smart buildings in the very near future.</p><p>Thanks for sharing!</p><p>Build_it_Bob</p>
<p>Very kind words. Thank you.</p>
<p>Hi! nice job:) for venetians check out http://www.indiegogo.com/projects/jalousier-adds-your-blinds-to-the-iot/x/4462109</p>
<p>nice , the 3D printed gear idea is amazing </p><p>i wanted to make a project like yours but i was wondering of a method to control the shade, now i got one! thank you. </p><p>but i dont have a 3D printer so im going to do with wood</p>
<p>Probably something like this? : wood cylinder, drill shallow holes for balls, file between holes?</p>
<p>great project!!</p><p>i really liked the part with the broccoli. ^^</p>
<p>Nice, I made a simple version of this a few years ago. This is way better, thanks for sharing!</p>

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