Sun projector

[lilimike]

I have this idea which I think can work. I have not started working on this project yet, I am still in the process of browsing but not finding much. I would like to get your opinions on this.

I have a few bushes in my yard that are under two large trees. At the beginning of the season (I am in Quebec so we start from scratch in Spring) all is good until the leaves grow on the trees at the point where it hides the sun from the bushes. The latter are not giving me as much flowers as they should.

My idea is to track the sun from a location where I have no shade on my yard and then scan the bushes using small mirrors with the reflection of the sun in the same way as a laser show and/or like an old CRT tube. The scanning idea is to reduce the size of the mirrors. I understand the bushes would only get a % of sunlight but a % is better than nothing and might be enough.

I foresee this project in 3 parts.

1 – Tracking the sun location based on a position on the earth, I have seen some code (Arduino) that does that so this is not an issue.

2 - I would then have to figure out how to redirect the reflection to a specific place in my yard with the option of sizing x and y axis. This part looks more complicated to me but in the worst case, I can manually change the position and log the data based on each day of the year for the first year.

3 – Since I’d be working with the sun and nothing would be needed if the sun is not out, I would implement solar as the power for this project (no problem there).

Any thoughts?

 

[audioguru]

Cheap solar panels get sunburned. Does a cheap mirror also get sunburned?
Is it legal to point a mirror at the sun and blind an airplane pilot?

 

[DJL33B]

Have you tried extra water on the bushes? Trees 'steal' the water from surrounding plants. It was the only way I could get anything to grow under the trees, and it was necessary to water heavily every day.

 

[BR-549]

It never occurred to me that the mirror would be lower than the bush. One wants the mirror as high as possible. And still shine under tree foliage.

 

[crutschow]

I think that you would be surprised at the size of the mirror needed.

Again, why?
It's simply the size of the area you want to illuminate.

 

[Nigel Goodwin]

I think that you would be surprised at the size of the mirror needed.

So just a one inch mirror would be fine? - I don't think so

You could basically do with a mirror of a similar size to the bushes foliage, but anything approaching that would be OK.

 

[Nigel Goodwin]

Have you tried extra water on the bushes? Trees 'steal' the water from surrounding plants. It was the only way I could get anything to grow under the trees, and it was necessary to water heavily every day.

That's actually a very good point - if you walk though dense woodland there's little vegetation growing underneath, probably due to a lack of sun, lack of water, and lack of nutrients?.

 

[audioguru]

How will you turn the mirror so it follows the sun across the sky?

 

[BR-549]

I have never done so, but learning how to track the sun would be a start. I assume there are tables or calculations that can give the azimuth and inclination angles of the sun for any time and location. A perfect function for micro controllers. An accelerometer for surface and direction reference and accelerometers for panel azimuth and inclination. This can keep the panel...normal to the sun.

If we reference another direction and therefore another angle to that mirror panel.....And bisect that angle with the sun angle....with the normal of the mirror......that should keep the sun beam pointing at the bush. That bisecting angle will be constantly changing and the micro controller will have to keep track of it. Time and table updates thru wifi. Once perfected, more than one mirror at different positions could be used for one focal point.

Does that make any sense? I'm sure there are other strategies and methods for this function. Perhaps tracking the sun with a sensor.....instead of a table or calculation. And perhaps a sensor at the bush.

If you add a bending function(a foil or film) to the mirrors one might heat a pool..... or one might melt and clear the driveway of ice and snow. Too much?

 

[Nigel Goodwin]

Does that make any sense? I'm sure there are other strategies and methods for this function. Perhaps tracking the sun with a sensor.....instead of a table or calculation. And perhaps a sensor at the bush.

Just use sensors, it's a VERY, VERY common practice, and simple to do - check out solar panel trackers.

 

[danadak]

An array of solar power source coupled with an array of UV COB LEDs to supply
the wavelength of life ? Get rid of mechanical movement systems.

Use a Fresnel lenses in reverse to disperse light from smaller "point" sources like
LEDs. The plastic sheet versions.....


Regards, Dana.

 

[Nigel Goodwin]

An array of solar power source coupled with an array of UV COB LEDs to supply
the wavelength of life ?


Regards, Dana.

Nice alternative suggestion

But efficiency would be low, and cost would be high - and you would need MUCH larger solar panels than you would a mirror - a mirror is effectively near 100% efficient.

 

[danadak]

No moving parts. reliability. Dont even bother with panel tracking. Simplicity.

Cost for a couple of bushes......meh.....

Supercap battery for cloudy days.......

Nice alternative suggestion

 

[shokjok]

Ambitious project, considering the size of the bushes and the available space. You may need a light differential sensor project that reads the sunlight and moves a rotating mirror - the sun also provides solar power to the project, saving you from paying extra to Hydro Quebec. The only calibration is the maximum intensity reading on a CdS cell feeding a variable voltage divider, then using two CdS cells feeding separate voltage dividers to read the sunlight and move the rotating mirror based on the results. At sundown, the rotating mirror would be reset daily to the sunrise position.