We’re past the winter solstice and the days are getting longer, but that doesn’t mean we’re not sick of the sun setting around 5 in the afternoon. There is a way to get more sunlight through our windows – a heliostat. Lucky for us, [Gabriel] sent in his Open Source Sun Tracking / Heliostat project that can reflect sunlight through our windows all winter long.
Using mirrors to brighten up a room is an ancient practice; a few thousand years ago, heliostats went by the archaic term, “slaves.” Luckily there’s a far more elegant way of doing things nowadays – an Arduino. [Gabriel] came up with an Arduino sketch that calculates the altitude and azimuth of the sun using only latitude, longitude and time zone. [Gabriel] used this sketch to drive a pair of stepper motors and reflect sunlight through his window.
You can check out [Gabriel]’s demo of his heliostat after the break.
Continue reading “Arduino heliostat calculates the position of the sun”
[Frits] has been working on an solar panel heliostat (in Dutch, check out the translated page here).
The heliostat uses a small PICAXE to control the motor, along with an DS1307 real-time clock to make sure the motors start at dawn. Instead of using optical encoders or magnetic sensors, the angle of the heliostat is measure with a pot attached to the drive shaft. [Frits] did a lot of data collection to figure out that this method is accurate to about 1 degree – just fine for something that doesn’t need to be exact.
According to [Frits] this heliostat will put out 12 to 50 percent more electricity than a fixed panel. Although the build does seem a little bulky, putting it on a house with a roof pitch of 23.5° would greatly reduce the horizontal profile.
A video of a solar panel rotating at 15 degrees/hour isn’t that interesting, so [Frits] posted a clip of 6 mirrors slewing around fairly fast to demonstrate his system. Check it out after the break.
Continue reading “Building a solar power heliostat”