Adapt a Clock Today! Cheap Trackers Boost Solar Panel and Solar Cooker Performance.

48,027

86

31

Posted

Introduction: Adapt a Clock Today! Cheap Trackers Boost Solar Panel and Solar Cooker Performance.

The Sun's path across the sky has been known and has been predictable for a very long time. People with solar panels and solar cookers take either a high tech approach to solar tracking (light detecting electronics, etc or they manually adjust the cooker or panel. High tech is very expensive and manual adjustment is majorly error prone.
Low tech cheap tracking could improve solar performance substantially.
Low tech tracking would be valuable in really poor countrys for solar cooking and perhaps save many trees from the cooking fires.
This instructable describes my tracker that I made from an old and ugly clock.
This is a collaboration so if you have an old clock lieing around, please set it up with a gearwheel as I did and see how sturdy it is. If we can find a strong robust one, It could be bulk ordered for appropriate tech solar timing projects.
Brian

Step 1: Stripping the Clock

First thing I had to do was to take the hands off the clock.
The hands are attached to 3 concentric shafts that are connected to the gear wheels in the clock
I had to find the wheels inside that turned the minute and second hand and cut off the pieces that went up through the middle. therefore I was left with the shaft that turns the hour hand. The hour hand is friction fit onto the shaft.
I wanted something stuck on much more firmly!






Unfortunately I dropped the clock during my taking it apart and I cracked the connection to its face.

Step 2: Fitting a "gearwheel" to the Clock.

Here is the central post of the hour hand. I will fit the piece of plastic tube to it and use the peice of tiewire to join them together really strongly! Then I slipped an old medicine contianer lid over it, screwed it to the plastic and put on the top pice of the medicine container. This now was the timing device for the new tracker!
As the clock turned, the twine slowly unrapped from the lid. The lid was almost exactly 2 inches wide. This means it releases (2 pi r) 6.28 inches of string in 12 hours.
My tracker has a float in water which has 8 inches of travel before it hits the bottom. This means I can track the sun for 15 hours with this clock!
clocks are weak but the weak tick, tick, tick movement is slowed and strengthened by 60 times to move the minute hand and slowed and strengthened another 60 times to move the hour hand. 3600 times the strength should be able to move what I want!

Step 3: The Float and Container.

A float 6 inches high is made from a bucket. This float is then attached to a metal holder and put in a slightly bigger (wider) bucket. This float will weigh 5 or 6 kg when it is full of water.
The container bucket will have a little hole screwed in its bottom and a pipe will be inserted. This pipe will be attached to the string from the clock. As the clock turns, the string comes down the pipe drops and water drips out through it from the container!
Phew.
There is more.
The float drops, and pulls the green string, this turns the solar cooker and pulls up the counterweight (the one liter drink bottle).
You can see the solar cooker on the next page.

Step 4: The Solar Cooker.

It can be a funnel cooker, a panel cooker, or something like what i made here. Tracking is not perfect with this simple tracker but good enough for these types of cookers and a whole lot better than no tracking at all!
I used a lazy susan. I had some waste thin plywood, I bent it to the curve of the susan, and cut some off the 2 ends from the middle to the edge at the bottom so it leans forward a bit.
Then I used flour paste to stick the kitchen foil to it. This sends the light down to the mason jar (which is covered by a plastic bag to slow heat loss.
I had to join a 4 inch diameter cylinder at the bottom of the lazy susan to act as a gear.
4 inches because the clock turns at 30 degrees per hour but the sun moves at only 15 degrees per hour. The coffee container was the perfect size!

Step 5: Testing Testin Testing!

I used this clock to do a demonstration once before but this is the first time I set it up to actually run a solar cooker. My test was run from about 5 30 in the evening till about 7 pm. Not the ideal times, to be sure.
Here are some pics from the first test. With the sun heating up some molasses in a mason jar covered in a crinkly plastic bag.
It started off cool but soon got up there!

To reset your clock for the morning, all you have to do is wind on the string twice (That coresponds to 24 hours) and fill the bucket with water. It will start tracking in the morning again at exactly the same time! So you can heat up water for a nice cup of solar tea when you get up!
Note, this does not exactly follow the sun. To do that, either one of the wheels would have to be eliptical (for more accuracy) or for great accuracy, the solar cooker should be mounted on an Equatorial or Polar mount. (2 different names for the same thing!).
I used the lazy susan to recycle it and because I did not have to deal with centre of gravity issues (as I would have to do on equatorial mount) and because this instructable is chiefly about the simple clock based tracker.
Brian White

Share

    Recommendations

    • Microcontroller Contest

      Microcontroller Contest
    • Science of Cooking

      Science of Cooking
    • Pocket-Sized Contest

      Pocket-Sized Contest
    user

    We have a be nice policy.
    Please be positive and constructive.

    Tips

    Questions

    31 Comments

    You could also try a small motor out of an old microwave oven, they are used to spin the microwave generator 'scatter' plate as well as the food turntable. They have metal gears and spin at ~ 2-8 rpm. Just an idea, I have used them to create turntables to show off my motorcycle models. (Unfortunately, the pictures were on my old PC which suffered an untimely death.) Wonderful idea.

    Brian, ,

    Excellent...thank you for posting your great tracking unit.... And to those who have been critical of Brian's work, the ' you need to do it this way' or why didn't you do this, add that....and so on.... Get to your drawing/design boards, spend the time, build a unit, take pictures, make a video, make drawings, diagrams and charts and write up step by step directions, with material lists.....then post it here for man kind to have at its perusal ....and be sure to ready to be bombarded with cynical criticism.....

    Brian, that you for sharing your design, saving me hours & hours of R&D, it is refreshing, indeed, to have people like you, share their findings w/out expecting anything in return but those following having success .... And benefiting from their hard work....

    I wish you health, happiness & prosperity....again, thank you for this post & look forward to more in the future

    Richard, sie

    Rancho El Starvo

    Te Jas, on the Red River, half a mile south of Native America aka Oklahoma

    image.jpg

    Hi, thanks, it is not that great, I never did find a clock that was stronger. After that I went on to making drippers for gardening that would probably work better than the clock for rotating the lazy Susan.

    https://www.flickr.com/photos/52815627@N06/8036249196/ The drip from that is very reliable, probably nearly as good as the clock and I have done it in 5 gallon bucket size too with dog dishes or aluminum dishes as the float. It is tough to get round to everything because my job takes a lot out of me. Anyway, if you do any new solar cooking stuff, I recommend the float and dripper as a better way of controlling a rotation. Brian

    The Intermatic Timers used for sprinklers water heaters etc, have a pretty strong clock motor to trip the switch inside. But they come with their own problems, not exactly cheap or commonly thown away & they need 110 V (or depending on model 220 V ) to run.

    Fantastic. Who needs it to be totally accurate? This is an ideal solution - thanks for a great post...

    could you not just have the clock turning a small solar oven ontop of it?

    Clocks are weak, there would never be enough power. You have to multiply the power somehow.
    And clock gears are really weak. A tiny gust of wind will strip the gears.
    Hope that helps.

    Can you say Rube Goldberg machine? This is really a cool idea. I have never seen or heard of it before and I definately like it. I think it has great promise. Good job.

    I think it is unfair to call it a Rube Goldberg machine. The float and bucket of water act both as ballast and as protection against wind damage for the clock driver. If you want Rube Goldberg, try letting the water dripping out of it onto a vegetable patch! I made a 2 bucket version where the water drips out and raises a float in another bucket (instead of having a counterweight) but it was a pain to take the water out of the bottom bucket at the end of the day! (definitely a more poetic version though!) Simple trackers are needed in poor countries for solar cooking so I invite people to make their own and make better versions. Think of it as volunteer work in your back yard! Brian

    It just reminded me of a RG machine, didn't mean to offend . I think it is a great idea.