DIY the Sky Follower Lamp With Polar Alignment

It all starts when you look at the night sky and all you can see are clouds! Needless to say, if you are a great night sky enthusiast, this is pretty frustating. To spend the entire night stargazing, admiring the plenitude of the thing that intrigues scientists and lovers since the beginning of everything. Well now you can at least try to entertain your girlfriend, wife or even your kids!

The concept of this lamp is based on the fact the earth is moving! Just as simple as that! Most of the star lamps are static giving you a false pespective of what is heppening outside your room above all the clouds blocking the view. A sky follower lamp with polar alignment would give a much clear pespective of how the "sky" is moving.

Step 1: What You Will Need!

Well, to bring this project to life you will need a few parts and tools.

• a 3D printer or 3D printer service
• 1 long M3 bolt with nut
• a very small LED strip (you can do it by yourself), or a thin light source
• Hot glue gun and stick
• 6cm diameter cilindrical plastic bottle
• a pair of scisors
• a pair of pliers
• a 30cm ruller
• 1 electrical plastic wall box with cover (10cm x 10cm)
• a sharpie
• an arduino uno
• 28byj-48 stepper motor + uln2003 driver
• one 8mm inner diameter bearing

The 3D printed parts you need are:

Step 2: Let's Put It All Together!

The first thing to do is to prepare the main part of the lamp, the starry tube. Take the bottle and cut a 10mm long section, use the sharpie to draw a line at the botom and at the top of the bottle then cut if using a pair of scisors. You should end up with a transparent plastic tube section. Depending on how did you get the 3D parts try to test if everything fits together allright. If not just use some sand paper or a file to clean up the parts. Put the bearing on 3D printed part D. Parts A and D should fit tightly at both end of the tube. Just a tip, try to put first part D pushing it against a flat surface and then use a pen or pencil to push part A the same way. Assemble part F and E using a bolt and nut, tighten it just enough to keep it steady once you move part E to get the polar alignment. Hot glue the assembled parts E and F to the plastic electrical box cover. Drill a hole on the center of part B, it needs to be big enough to allow the shaft of the sepper motor pass through it. This stepper can be hot glued to stay in place. The notch on parts B and C should fit on the top of Part F. Drill a hole at the center of part A the size of the stepper motor shaft. It must fit tightly to allow the stepper to turn the tube once everything had being put together. For a 6cm in diameter tube, you will need a 10cm (tube hight) by 18.9cm (tube perimeter obtained using P=2*pi*tube_radius) rectangular piece of paper. Punch holes on it using a needle in such a way it represent the star pattern you want to see. This piece of paper should be taped to the cylinder from outside, just for convenience. You can change it whenever you want.

The source light was home built. I used a narrow piece of perfboard and soldered some SMD LEDs, making it thin enough to pass through the part C center hole. The same part should be connected to the bearing on part D.

That's it the lamp is assembled!!!

Step 3: Let's Power It Up!

Well, the lamp is an Arduino based project, so let's use the Arduino. A very good explanation on how to use the Arduino to control the 28 byj-48 stepper motor can be found on https://arduino-info.wikispaces.com/SmallSteppers. Based on this project the electrical conections were made. The 3.3V output on the Arduino uno board was used to power the LEDs. Each board have plenty of room to fit inside the electrical plastic box. Once everything is wired up just menage the wires through one of the openings at the side of the box and cover it. Use the screws that come with the plastic box to close it.

Chage the firmware attached to suits the rotation velocity you find best. You can do it by increase the value at the line:

myStepper.setSpeed(Value);

This will increase or decrease how fast your projected stars will pass.

Step 4: Turn It on and Get Amazed!

As was said, this lamp concept uses a polar alignment to give a good representation of how the sky behaves above your head. To align it properly just turn the base pointing the N-S axis towards the North pole star and tilt the tube axis to point it directly. To find the North pole star you can use Google sky map on your smartphone. After set up just turn on the Arduino, turn off the light and enjoy it!