Previous in Forum: Energy of the Phase Change in Condensation -- Where Does it Go?   Next in Forum: Wind and Solar Energy Becomes Cheaper than Coal
Close
Close
Close
7 comments
Guru

Join Date: Nov 2007
Posts: 678
Good Answers: 8

Maybe Restarting My Solar Experiments, Fixing Past Failings

05/26/2021 3:50 AM

When I was younger and idealistic and not skilled enough, I tried making good solar cookers on equatorial mount. I think some of my ideas were good but I couldn't put them into practice and collaboration was pretty limited. Other people pretty much refused to work on "my" ideas, I think that using buckets and floats is a good way of moving and stabilizing big reflectors, especially if it's windy. Gusts can do damage to gears, Etc but not much they do to a float. . I think the way forward is pendulum timing of the moving of solar cookers. https://solarcooking.fandom.com/wiki/Solar_tracking contains some of my stuff and https://solarcooking.fandom.com/wiki/Ideas_for_low-tech_solar_tracking has some more. The problem was a "water clock" is not accurate enough or repeatable enough to run the timing of turning a solar reflector. I made one with a float with a hole in it and it's pretty good, just not the required accuracy when the buckets aren't perfect cylinders, (they are cone sections). But an escapement, pendulum and weight would be accurate enough. There is not need for any of the extra gears that run a clock. The weight attached to the escapement mechanism, powers the pendulum and as it drops, the float (attached to it) drops too. So it's a pretty minimal timing system. As long as we can get the weight to drop at an inch per hour or say 2 cm per hour, we can work things out so that the equatorial mount will turn evenly throughout the daylight hours. But, I looked up on Amazon and ali baba and there are no pendulum's and escapement wheels for sale. Can I DIY or is there some other solution? I did try using a battery operated clock to lower a float years ago, but they have extremely weak motors, not able to lift a small float in the water. I thought stepper motors (with say, 15 minute steps) but I haven't a clue what to buy or how to set it up. So, anyway, the thing would be very simple, just the escapement, the pendulum and the weight, (because we don't need all the gears that run clock hands. By the way, someone recently commented on one of my videos and said that one of "my" ideas was thought of almost a hundred years ago by a Portuguese priest. The video of his work (In French but you can translate with google) is pretty amazing. Here is the link

https://www.youtube.com/watch?v=jorwI9dg1g4

Suggestions appreciated, Link showing how escapements work is below. Thanks, Brian White

https://en.wikipedia.org/wiki/Escapement

Register to Reply
Pathfinder Tags: solar timing tracking
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Guru

Join Date: Jul 2008
Posts: 1569
Good Answers: 139
#1

Re: Maybe Restarting My Solar Experiments, Fixing Past Failings

05/26/2021 6:43 AM

Something like a low cost Arduino board controlling stepper motors and a simplistic set (possibly 4 or 5) light sensors to providing aiming information seems like the best way to go. With light sensors you possibly could use belts rather than gears since it would self-correct and not need any "absolute" position information.

Probably the best initial question is why are you trying to do this? Buckets and floats, pendulums for timing, etc. all sound rather duct tape (Rube Goldberg). Is this just a hobby? Are you trying to save the planet? Are you preparing for life after our economic system falls apart in another year or two? Is this for third world countries that don't have any way to cook? How critical is cost? How critical is weight? Is electricity available?

An equatorial mount with a stepper and gears (or belts) driving it sounds like a simple block diagram. Make it strong enough for non-hurricane and non-tornado winds and you should be good to go.

You might do better at getting help if your task is framed a little better. What is "in scope" and what is "out of scope"?

__________________
Few things limit our potential as much as knowing answers and setting aside questions.
Register to Reply
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 6933
Good Answers: 253
#2
In reply to #1

Re: Maybe Restarting My Solar Experiments, Fixing Past Failings

05/26/2021 12:06 PM

Build a rack of collimator slots,using black pvc pipe.The smaller the pipe,the more resolution you will get.Around 12 inches long should suffice.Longer is more sensitive.

Paint the inside with flat black paint.

Allow the light from each tube to shine on a photo-resistor.

Parallel all photo resistors.

Apply a dc voltage through a resistor to the photo resistors.

The resistance will decrease as the light intensity increases.

This resistor in series with all of the photo cells will be a summing resistor.

The voltage drop from this resistor can be fed into a op amp,and the output (analog) used to determine how many resistors are being illuminated.

An A/D converter can be used if you desire a digital output.Your choice of type;Single slope will probably be adequate for your use.

Scaling of the output is up to you for your particular purpose.

This signal can be used,with appropriate hardware/software, to adjust the mount.

This is a very simple circuit,and can be made much more complicated ,but unnecessary for your purposes.

__________________
"A man never stands so tall as when he stoops to help a child." "Never argue with a stupid person.They will drag you down to their level and beat you with experience"
Register to Reply
Guru

Join Date: May 2018
Location: Under the spreading Bunya Trees, South Burnett, Queensland, Australia
Posts: 658
Good Answers: 59
#5
In reply to #2

Re: Maybe Restarting My Solar Experiments, Fixing Past Failings

05/27/2021 4:57 AM

I made a sensor out of LEDs and used their ability to generate a voltage when the sunlight fell on them. A configuration of 19 LEDs set out like the cores of a cable worked well for when the center LED is producing maximum voltage the array was aligned correctly any other combination of voltage from other LEDs, more than the center LED told the processor which way the motors had to be driven to return to equalibrium.

The processing was done by a picaxe chip and two gate opener driver were used.

Mind you this was all experimental and once proved it was repurposed to other projects, especially the gate openers, sure missed the auto gate opening.

__________________
Hare today, goon tomorrow!
Register to Reply
Guru

Join Date: Apr 2010
Location: About 4000 miles from the center of the earth (+/-100 mi)
Posts: 9249
Good Answers: 1049
#4
In reply to #1

Re: Maybe Restarting My Solar Experiments, Fixing Past Failings

05/26/2021 3:39 PM

I agree. It seems that a combination of equatorial mount and servo system should be able to track the sun. A shade with an aperture and a pair of solar cells should suffice. One solar cell would be illuminated if the mirror were behind the sun and the other if it were leading the sun. Wiring the solar cells in series with opposing polarity would generate a correction voltage that could be amplified and drive a DC tracking motor.

Register to Reply
Guru

Join Date: May 2006
Location: Placerville, CA (38° 45N, 120° 47'W)
Posts: 6039
Good Answers: 245
#7
In reply to #4

Re: Maybe Restarting My Solar Experiments, Fixing Past Failings

05/28/2021 11:31 PM

Yep. 30 or so years ago, in my electronics classes we made little 'robots' that would follow a light around the room. The circuit consisted basically of two photo-resistors connected to two low power transistors that drove 2 higher power transistors that in turn actuated 2 small DC motors or gearmotors. This could easily be adapted to power an equatorial mount system. If the equatorial system is anywhere close to being balanced, very small motors would be quite adequate.

I can no longer access most of the drawings I made that far back (using MacPaint and SuperPaint), but I think I still have one of the units with its motors...

__________________
Teaching is a great experience, but there is no better teacher than experience.
Register to Reply
Guru

Join Date: Mar 2007
Location: by the beach in Florida
Posts: 31843
Good Answers: 1750
#3

Re: Maybe Restarting My Solar Experiments, Fixing Past Failings

05/26/2021 1:49 PM

Passive solar tracking has fallen by the roadside due to cheap solar panels and cheap electronics that work better and more reliably....

__________________
All living things seek to control their own destiny....this is the purpose of life
Register to Reply
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 6933
Good Answers: 253
#6

Re: Maybe Restarting My Solar Experiments, Fixing Past Failings

05/27/2021 6:44 AM

An old C-Band linear dish actuator is a good candidate for your movement.They are available with up to 1000 pounds lift capacity,and are very reliable.Some have a recirculating ball drive,while others use a screw,but both are dependable and accurate and allow relatively fine control.

__________________
"A man never stands so tall as when he stoops to help a child." "Never argue with a stupid person.They will drag you down to their level and beat you with experience"
Register to Reply
Register to Reply 7 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Copy to Clipboard

Users who posted comments:

BruceFlorida (1); dkwarner (1); HiTekRedNek (2); Rixter (1); SolarEagle (1); Stef (1)

Previous in Forum: Energy of the Phase Change in Condensation -- Where Does it Go?   Next in Forum: Wind and Solar Energy Becomes Cheaper than Coal

Advertisement