Quick`n`Dirty Heliostat – Get some sun into your home

Written by: admin@makezilla

This is work in progress...

I just want to give you an impression on what great effect a simple mirror in your garden might have on your life, well-beeing and energy consumption... Please try it for yourself!

My girlfriend and me live in a nice, quiet, green, but still urban place.
We are surrounded by other buildings, we have a nice lawn with direct sunlight in front and a little garden under tall trees in the back.
Well, I really can not complain about those things.

BUT our flat itself is like a cave and pretty dark. You have to turn on the lights even at noon time in summer with a cloudless sky. Pretty cozy in wintertime though.

So today I just wanted to try out, what effect a heliostat could have. Had this idea in mind for years now, but never really tried it.

The effect was AMAZING! And I will definetely put some more work in it in future.
I was only using an old mirror of 55 x 35 cm (0.19 sqm) and I never saw my home office that bright before. (Made me realize that it could need a thorough clean up,... *cough*...nevermind...)

First pic is the "heliostat" (or better adjustable mirror, since it´s not self-aligning yet), second is my room without artificial lighting AT NOON, third pic is with mirrored sunlight (2nd and 3rd pic for comparison at the same time; same aperture, exposure time and ISO setting).

Materials (which I used, the setup is so simple that you can use anything laying around which fits the purpose):

- an old mirror I found in a garbage pile in the basement (used for testing, you can get mirror tiles for about 0.27 sqm via amazon for 9,99 € or 7.33 $) (and I will get loads of them, hrhr)
- an old document holder 
- an old TV-Turning platform, this one was from IKEA 
- screws / screw hooks
- some rope/cord


- a drill might be useful, but you can do without (We´re just testing/getting an impression in this step)

- some scissors

- your eyes

Step 1: Testing

Basically, the only thing you have to do is setting up a mirror in direct sunlight and align it´s reflection towards the window of the room you want to have more (sun)light in. Just place the mirror on the ground and support it with a gardenchair or whatever fits.

Now go back inside and watch the result.

Step 2: Awesome or what...

I never saw my room in such bright light before. 
Got 140 W of halogen lamps plus a 100 W standard lightbulb plus indirect light through the window. All combined not slightly as bright as the 55 x 35 cm junk mirror... not to mention the light quality.

For testing purposes I simply attached some strings to the base. Works for horizontal "tracking" and for switching from bureau to living room "remotely". Vertical tracking is yet unsolved.

But this was only a three hours first test which proved the great potential, usefulness and DIY-capability of that technique. 
I´m looking forward on the effect of 2 x 2.7 sqaremeter of pure sunlight shining in our "cave" ;)

Found several tutorials on the net regarding tracking of solar panels and heliostats, check them out.
Go on and build your own, as I will do and tell me your experiences, please!
Will update as soon as I can!

[Edit: See next page for updates.]

Step 3: Poor mans' linear actuators

Today I worked on the vertical tracking.

I´m still lacking some appropriate motors and gears so my cordless screwdriver had to serve as a substitute to check the technical feasibility.

A threaded bar and a fixed nut work astoundingly well as a linear actuator.

The fixtures are from metal construction kits I stumbled upon in a 1$/1€-store. 
If you happen to see some of those kits for 1-2 €/$, BUY THEM ALL (ore maybe at least 2-4), the parts come in pretty useful for all kinds of projects. 
And you probably won´t get those any cheaper anywhere!

To be continued...

Step 4: Bigger and concentrating mirror (stainless steel)

Quick update (more details to come):

Ordered some sheet metal for experimental use via amazon marketplace.

Not that cheap, but not as expensive as one might think.
1500 x 500 x 0,8 mm stainless steel with mirror finish for about 25 € + shipping.
Easily bendable, so suitable for a concentrating mirror.

See the effect in the pictures.

Warning: NEVER look directly into the concentrated light! Avoid exposing your skin to the concentrated light for longer than a few seconds!

Got a pretty nice one-sided sunburn in my face trying to clean my window while the mirror was oriented to it...
In less than five minutes.