Redrok sun tracker experiment

[David HK]

I recently took an interest in the Redrok sun tracker and made up my own copy of the circuit and had it produced on PCB's from PCB Express. A total of six PCB's were made and one was populated with the same components specified by Redrok.

The web site reference is here:- http://www.redrok.com/led3xassm.htm#led3xc3

A test pole was erected and an old satellite dish hub mount was equipped with a 36 volts DC actuator. The power supply for the test was 12 volts DC so this meant that the actuator ran slowly which is useful for sun tracking.

After observing the operation for several days in different weather conditions I was able to reach the following conclusions:-

If you live somewhere in the world where there are no clouds all day and everyday of the year, then the sun tracker is the best thing since sliced bread.

If you live in a normal place like me and have every imaginable weather condition (except snow) then the sun tracker will track all over the arc (East to West) and try to settle on the brightest area of sky. Since cloud thickness is forever changing the tracker motor would buzz away to the point where I got fed up with the motor noise.

I decided to implement some changes and replaced a 100uf capacitor with a 1,000uf capacitor which slowed the operation down, but did not stop the constant hunt around the sky. I tried various values of variable resistor which seemed to have little effect.

I then built the reverse inhibitor circuit which made the circuit ‘stand still' and despite making adjustments with the variable resistor I could never track the sun successfully. Sometimes the tracker would be quite a long way ahead of the sun

As a result I became fed up with the experiment and dismantled everything.

I no longer require the new unpopulated PCB's and the populated single board and shall be happy to give them away as a ‘job lot' on a first come first served basis. There are sufficient extra unused components to populate a new board. Those readers experienced in basic electronics should not have a problem.

Please contact me by signing-in to the board and leave a PM with your correct name and address and I will ship the lot off by airmail.

In the meantime I am pleased  to report that the LM339 sun tracker circuit I built 4 years ago continues to give me faithful and flawless service.

David in HK

[joestue]

with a ti launchpad costing $4.30... stepper motors from an old printer geared down 1000:1, only need like one watt or less to run.
there's code out there, i just don't know any C.

[dave ames]

I dont know why someone here hasn't designed and built a simple 12v timer based solar tracker,.....Seems so obvious to me, unless I may have missed something 

  i seem to recall, sometime last august someone designed, built and tested a fully automatic time based tracking system right on your open forum without much interest? 

 i hear it's been running ever since.

it's all good fun,
cheers, dave

[Fused]

Hello,
I would love a kits worth. Not sure Im understanding the "lot" thing. 

Let me know if just 1 kits worth could be mailed. Id be happy to pay shipping.


Thanks
Fused

[David HK]

Fused,

"Job lot"  means you receive all the PCB boards, and everything else associated with the circuit layout I can give you for free.

I really don't want to play with this circuitry again. I will also throw in data sheets for various transistors, H Bridges, and everything else.

You or anyone else who wants to play with this circuitry are more than welcome.

Consider it to be early Christmas!


David HK

[DanG]

I'd love to but I'd be lynched by S4w and a few others for my non-performance on earlier device & projects that fell into the black-hole gravity well my work bench has turned into.

[Bruce S]

In the meantime I am pleased  to report that the LM339 sun tracker circuit I built 4 years ago continues to give me faithful and flawless service.
David in HK

Hello David;
There as been a whole new breed of members here since the board update. If you have the time  .
Could I ask a small favor and maybe re-post your write up with updates.

I'll catch up on work and then do a quick search for the old post and link it here.
Thanks
Bruce S
 

[dnix71]

I've often wondered why the trackers try to follow a bright spot. Wouldn't it just be easier to program it straight clock motion and point the panels where the sun is, clouds or no.

You might lose a couple of watts if the sun is behind a cloud but I don't imagine it would be that much. All you need is to know the angle to the horizon at the highest and lowest point in the year and a daily lookup for each day in between. That's one axis. The other is simply sunrise time and sunset time and those can be looked up and compared against an internal clock. Tracking points are a combination of the two and could be undated every 15 minutes or so, stepwise. You don't even need smooth motion all the time just 15 minute steps. After sunset each day the tracker resets to the start point for the next day.

Astronomers tracking stars with monster telescopes have no trouble doing this. If clouds are in the way, there's nothing to do but wait until they move.

[Bruce S]

I've often wondered why the trackers try to follow a bright spot. Wouldn't it just be easier to program it straight clock motion and point the panels where the sun is, clouds or no.

You might lose a couple of watts if the sun is behind a cloud but I don't imagine it would be that much. All you need is to know the angle to the horizon at the highest and lowest point in the year and a daily lookup for each day in between. That's one axis. The other is simply sunrise time and sunset time and those can be looked up and compared against an internal clock. Tracking points are a combination of the two and could be undated every 15 minutes or so, stepwise. You don't even need smooth motion all the time just 15 minute steps. After sunset each day the tracker resets to the start point for the next day.

Astronomers tracking stars with monster telescopes have no trouble doing this. If clouds are in the way, there's nothing to do but wait until they move.

From reading the Redrok website more than I probably should, the idea of this was borne out of need for simplicity.
His testing of transistors and LEDs that produce a small voltage when shining into the sunlight was were he got his idea.
One thing led to another and now even with some bad publicity lately do to lack of timely support 
These can still be very simple way to go.
The look up tables will change, if you use the clock tables you'll run into a long table as well. Back before pic-controllers simple LED based trackers were the way to go, and in no small amount based on simplicity still are.

JMO  YMMV
Bruce S

[dnix71]

Bruce S - That makes sense. Tracking a bright spot in the sky is something heat-seeking missiles do, so there must been an analog way. But early heat seeking missiles were known to have trouble telling engine heat from the sun so I can see why a "simple" controller might be prone to wander.

Motors for telescope transit tracking are still analog but they are usually only single axis. It might be possible to adapt one of those.

[David HK]

Bruce,

The last Forum article I did on my LM 339 solar tracker was in March 2007. I have checked the articles and found some photographs missing.

In the next few days i will write a fresh article with new photographs and a link to the website containing the circuit drawing.

Is this what you have in mind?


David in Hong Kong

[Bruce S]

Bruce S - That makes sense. Tracking a bright spot in the sky is something heat-seeking missiles do, so there must been an analog way. But early heat seeking missiles were known to have trouble telling engine heat from the sun so I can see why a "simple" controller might be prone to wander.

Motors for telescope transit tracking are still analog but they are usually only single axis. It might be possible to adapt one of those.

Reminds me of the Herc missiles from the late 70s. 
 

[Bruce S]

Bruce,

The last Forum article I did on my LM 339 solar tracker was in March 2007. I have checked the articles and found some photographs missing.

In the next few days i will write a fresh article with new photographs and a link to the website containing the circuit drawing.

Is this what you have in mind?


David in Hong Kong

That's the one and yes.

[Seth7]

So what is the Best of the cheapest solar trackers around any time based ??

And who has a good "FREE" PCB design software?? I have finally nailed down a Time based approach that im hoping will not be too spendy.

[rossw]

So what is the Best of the cheapest solar trackers around any time based ??

I designed a simple, single-chip PIC-based controller, however for a plethora of reasons I never got past the first prototype but had 4 trackers assembled and just ITCHING for control.

Since my home is all C-BUS, in a fit of madness (or inspiration, depending on your viewpoint), I realised that I had some spare relay channels on a module in the battery room, and that anything I did in the c-bus system was a "zero-power solution" (since it was already running).

A few lines of code later, and I have my panels tracking a small amount every (approx) 20 minutes, from sun-up to sun-down. Half an hour after sun-down, the panels all move to a "centre point" where they (hopefully) present minimum wind loading. Then, half an hour before sun-up, they drive all the way east ready for the next day.

So far, while not necessarily "perfect", it's *WAY* ahead of the "panels locked at the mid-day position" *OR* "I manually adjust the panels with a east/west switch as and when I think of it, several times a day (if I'm home)" solution.

It's pretty ugly, but it works - and the only requirement was two, double-pole relays (one pole is purely as an interlock to prevent them ever both driving at once).

[zap]

So what is the Best of the cheapest solar trackers around any time based ??

And who has a good "FREE" PCB design software?? I have finally nailed down a Time based approach that im hoping will not be too spendy.

Cheapest???  Hard to say... but this design is very cheap:
http://fieldlines.com/board/index.php/topic,134964.0.html and the youtube video still works:
http://www.youtube.com/watch?v=j_yqBdbuKpg

[dave ames]

So what is the Best of the cheapest solar trackers around any time based ??

we have been running a time based positioning system here for the past year and a half that was put together with not much more than spit and stray parts..(never thought the prototype would stay together that long) 

i'm a cheap SOB so the cost was very low. the heart of the build is an off the shelf timer. the other stuff can be scrounged or built.

we are here on the cloudy east coast and it "tracks" rain or shine. a big surprise was how much power is still there on bad days when we have our module pointed where the sun is hiding!

the circuit:


the position encoder:


mount:


the controller as part of a hydroponics system:


more info about the build:
http://picasaweb.google.com/davidamesofsouthington/TrackerProject?authkey=Gv1sRgCLnO4azQ0IqU0QE#

this stuff is a ton of fun!

cheers, dave

[WindriderNM]

I saw a zomeworks one that used shaded tanks on each side that transferred a fluid or gas/fluid between them to keep it pointed at the sun the only moving part is the panels.

[WindriderNM]

The site for the passive trackers is zomeworks.com
A neat idea it looks like it could be make fairly easily.

[Seth7]

Fused,

"Job lot"  means you receive all the PCB boards, and everything else associated with the circuit layout I can give you for free.

I really don't want to play with this circuitry again. I will also throw in data sheets for various transistors, H Bridges, and everything else.

You or anyone else who wants to play with this circuitry are more than welcome.

Consider it to be early Christmas!

David HK

 Did anybody take you up on this??

[Bruce S]

The site for the passive trackers is zomeworks.com
A neat idea it looks like it could be make fairly easily.

Here's something similar that Mom Earth did a bunch of years ago.
http://www.motherearthnews.com/Do-It-Yourself/1977-11-01/Mothers-Super-Simple-Solar-Tracker.aspx.
Uses freon, but with the new stuff we're okay right 
Bruce S

[Seth7]

Until they find some microscopic frog that died off that scientists didn't know about .... and didn't care about into they were gone

[David HK]

Seth 7,

Yes, I sent the entire lot off to another forumite some time ago.

I originally followed and built the design shown at this URL 

http://www.phoenixnavigation.com/ptbc/articles/PCB%20Wizard%20-%20SUN%20TRACKER.pdf

and it has worked flawlessly and well for about 4 years now.

Good luck,

David in Hong Kong

[Ungrounded Lightning Rod]

The site for the passive trackers is zomeworks.com
A neat idea it looks like it could be make fairly easily.

Yep.

Don't forget the "shock absorber", which damps the motion to keep it from oscillating around the sunward direction and blowing around in the wind.

[Ungrounded Lightning Rod]

The site for the passive trackers is zomeworks.com
A neat idea it looks like it could be make fairly easily.

Here's something similar that Mom Earth did a bunch of years ago.
http://www.motherearthnews.com/Do-It-Yourself/1977-11-01/Mothers-Super-Simple-Solar-Tracker.aspx.
Uses freon, but with the new stuff we're okay right 
Bruce S

Or just use Propane if you're really cheap and really SURE of your joints.  B-)

[Ungrounded Lightning Rod]

The site for the passive trackers is zomeworks.com
A neat idea it looks like it could be make fairly easily.

Here's something similar that Mom Earth did a bunch of years ago.
http://www.motherearthnews.com/Do-It-Yourself/1977-11-01/Mothers-Super-Simple-Solar-Tracker.aspx.
Uses freon, but with the new stuff we're okay right 
Bruce S

Or just use Propane if you're really cheap and really SURE of your joints.  B-)

(But on the zomeworks sealed-tanks-and-shockabsorber version.  I wouldn't want to put propane behind the seals of the hydraulic piston in the motherearthnews version.)

[Bruce S]

The site for the passive trackers is zomeworks.com
A neat idea it looks like it could be make fairly easily.

Here's something similar that Mom Earth did a bunch of years ago.
http://www.motherearthnews.com/Do-It-Yourself/1977-11-01/Mothers-Super-Simple-Solar-Tracker.aspx.
Uses freon, but with the new stuff we're okay right 
Bruce S

Or just use Propane if you're really cheap and really SURE of your joints.  B-)

You are correct sir! Propane is actually better suited for this, but since it flammable, I didn't want to put that link on here.
Cheers;