Tuesday, 3 August 2010

So you know how I insisted that I wouldn't be leaving here until the prototype was working? Lies. Tomorrow I'm heading for the Ecotopia festival for a week.
There are three reasons why this is necessary.
First, I really need a break. I haven't officially shunned the project for more than three days since I was last in Edinburgh, in November.
Second, it's set to rain, and as the next step is plugging the tracking system together and seeing if it works, I'll be needing some sun.
Thirdly I've mounted up the collector and want to leave it for a while to see if it blows over/blows up/rips in half or gets messed around by the weather.

All plugged together it's still on about 20 grams to turn it, which is about a quarter what I was expecting.
So that's good news.

Wobbles like a bastard tho, haven't managed yet to devise a decent couple for attaching the collector to the main shaft. That'll get done when I'm back.


  1. Hi. I think you are the person that posted this question on two different boards:




    Your no-electric tracking system is amazing. I don't mean to take away from that. I just want to know if you resolved the issue in your question from a long time ago.

    I'm currently trying to make a cheaper version of fiber optic cable. I'd like to brainstorm with you about it. Some methods work and some don't. You can talk with me through this blog or give me an email to contact you. I'll comment again to let you know I have the email address and you can delete it from the post. Thanks.

  2. I've decided to go with a different option for transporting the energy, but did end up making a liquid core light pipe from silicone and mineral oil. It worked in principle..

    Contact me on solarflower.org at gmail.com

  3. I don't have access to my email right now, so I'll respond here for now. I tried mineral oil (well, baby oil because I couldn't find bare mineral oil) in a polytube. It worked great for about 6 inches but when I applied it to about 5 feet in a straight line I got nothing.

    Am I missing something?

  4. What's polytube?
    You need to use something with as low an index of refraction as possible, so as to create the total internal reflection which keeps the light from escaping the liquid core.
    The best stuff to use is teflon. AF 1800 or 2400 are the best, followed by FEP.
    I couldn get any of that, however, so used silicone. It worked ok for the t.i.r., but the problem with silicone is that it scatters the light due to the surface not being completely smooth on the micro scale. In the end with a one meter long pipe I was getting losses of around 90%.
    But if you can get the teflon it should work.

    Also important is how you're plugging the ends...

  5. polytube = plasticized PVC

    I did some research and realized this was my problem. I assumed the polytube I was using had a low index of refraction relative to the mineral oil. The articles I read also suggested teflon.

    As usual, I'm now moving onto a completely different solution. Oh well. Thanks so much for your help.

  6. Yeah PVC is super high. Shame, since it's so hard to get anything else.

    Was it to transport energy, for lighting, or communications?