Week 8 Update

Goals completed:

• Assembled window, including electronics
• Finished main version of light control algorithm
• Tested LEDs and sub-algorithms

This week we finally put together a working prototype of our window! It is not entirely complete, but it is at the stage where we can simply plug in the power cord and let it run on its own. Everything else is just minor polishing.

On the frame side, we finished the main assembly. We caulked the gaps in the corners that were caused by warping of the wood, as discussed in week 7. We mounted the back panel using a set of hinges screwed into the frame in order to allow access to the internals of the window. We also added a Velcro closure to the panel to allow it to be closed securely.

The back panel of the window, with hinges.

For the lighting, we attached the reflective sheet to the inside of the back panel using double-sided tape. We also mounted the LEDs on the inside edge of the frame, as planned. The distribution of light from this setup is still working has well as we had hoped based on last week's testing.

Inside view of the window.

Closer view of the LEDs.

We also began mounting the Arduino to the inside of the frame and constructed a port through which we connect the power cord. The Arduino mount works for testing purposes, but we still need to make a few adjustments in order to make it completely secure and to the wires remain well connected. In particular, the circuit board and the breadboard are mounted on the back panel, and the wires are not long enough to reach when the window is open all the way. We will try to either reposition the Arduino or extend the wires.

The Arduino circuit board (not mounted) and breadboard with their connecting wires detached.

On the software side, the algorithm for controlling the LEDs has been completely written, although not thoroughly tested. The way the code works, the LEDs change color over the course of hours or, at a minimum, many minutes. We did, however write a few testing programs for various parts of the algorithm and, in particular, the LEDs (as shown below).

Our window cycling through its different colors.

It is easier to test the LEDs with a program that simply cycles through each different color we use, as the above code does, than one that checks the current time. However, for presentation purposes, we would like to demonstrate our actual algorithm. We will need to adjust the code to allow it to set a day length of only a few minutes without disrupting the normal functionality.

The colors of the LED are also not set in stone. There are a few factors that make the current colors less than ideal: first, the color intensity to RGB algorithm we use is designed for photography color correction and may not match perfectly what the human eye sees in sunlight; second, color and intensity values for our light are from a nursing home schedule, which increases the brightness of light to accommodate elderly residents with poor eyesight. They are currently our best sources of data, but we will continue to search for other data or make adjustments to make the light more comfortable for our own eyes to look at.

Next steps:

• Ensure electronics are mounted securely
• Adjust code to allow demonstration of the algorithm
• Adjust lighting color and intensity as needed