Solar project ideas

I'll be working on the solar project with Tom Xia.

After discussing several ideas we found that we were both interested in visualizing the trace of something over time. Because this is a solar project, we thought it would be interesting to capture the trace of the sun's UV rays for the duration of the project.

The current plan is to build a square-shaped box whose top face is a perforated. The layer below that would be photo-sensitive paper that would get hit by the sun's rays throughout the day and visualize its movement. The perforations could be:

1. A matrix of tiny holes
2. A number of slits all across the surface, with a covering mechanism that exposes just one every day and progresses from one to another as each day passes.
3. One dot in the middle of the surface.

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The actual duration a ray of light shines through the hole onto a specific point will be quite brief due to the Earth's rotation — approximately 15 degrees per hour (rough estimation). As the Earth rotates, the sunlight's angle changes, moving the spot of light across the surface behind the hole. The movement of this spot means that any given point on the surface receives direct light through the hole for only a short period each day, possibly just a few minutes — just enough to leave an impression on the paper. Due to the angle it might also create not just dots but lines that would visualize directionality (that would also depend on the distance between the two layers).

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The final product of the project is intended to be an archive consisting of all the traces imprinted on paper — hopefully visualizing the sun's slow but steady movement, emphasizing the differences in movement from one day to the next.

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Questions / challenges

1. If we're doing one paper a day we need a mechanism for changing papers that could be powered with the energy generated by the solar panel. Changing papers is a delicate task that might be too risky to try and automate. We're still considering other options, perhaps a piece of fabric / a long paper that is slowly being pulled by a motor.
2. We're still not sure what kind of photo-sensitive paper would work best, as most of them are too sensitive for our purposes and would get completely washed out if exposed to the sun for more than a few seconds. So far Cyanotype sounds like the best candidate as it is relatively slow, cheap, and doesn't require any special chemicals to develop. We can also try to weaken it by diluting the solution as needed and find a ratio that works for our specific duration and location.
3. The intention currently is to use the solar power generated by the panels for timed and relatively small movements, which shouldn't require too much power. That said, we will probably need to charge a battery / a capacitor and only actually activate the motor when the sun is down, otherwise it beats the purpose.
4. There are a lot of tests to run regarding the paper, exposure strength and so on, as well as designing and fabricating a mechanism that has to remain functional for at least a number of days outside. We are hoping that after the class' visit to the site we'll know a bit more on how to prepare for that and make the needed decisions and / or adjustments.