This star projector works like a pinhole device so if you add more lights inside, there will be more “stars”. BE ÜBER CAREFUL! These LEDs being used are really bright, if you stare straight at them, you will most definitely get a headache for a few hours.

Step 1: Materials & Tools

Materials:
- 2 sheets of 12 x 20 black museum board or something comparable.

- A battery pack from Radioshack that hold 4 AA batteries. (total output 6V)

- 1 (or 2) super bright LEDs. I used two of these https://www.sparkfun.com/products/9658? (They are rated for about 3.15 to 3.99V and max 700mA)

- Since these LEDs draw a lot of current, be sure to make a bundle of resistors in parallel to handle the current, or else things might catch on fire. One bundle of resistors for each LED. I used three 470ohm resistors plus one 4.7ohm. (you want something low around 4.7ohms as the resulting total value. Use any combination, just make sure your math is right.)

- Optional – (If you want it to spin) A pretty torque-y dc motor with some kinda platform for the thing to sit on. I ran it at 3.3V, off of an independent power source.

Tools:
- laser cutter

- soldering iron

- hot glue gun

Step 2: Laser Cut!

File can be found HERE!
Cut the red lines & score the black lines.

After you cut, you’ll have to poke out the circles with something tiny and sharp.

planetarium_projector_01.ai
Download

Step 3: Build It!

- Fold along all the score lines slightly, you’ll start to see the shape immediately.

- One tip: peel off half the layer of the scored tabs, it’ll make the whole shape fit a lot better when you get to gluing.

- Get to glueing! I used hot glue for a quick fix. You can also use krazy glue of you want, just something fast drying.

- When glueing the second half of the thing, leave one of the panels open without glue so you can get the LEDs in.

Step 4: Wire Up the LEDs and Battery Pack

I used three 470ohm resistors plus one 4.7ohm to get close to a final amount of around 4.7ohms. Having 4 resistors in parallel allows it to handle a full amp of current.

Solder the resistors to the LED and wire it up to the battery pack.

Step 5: Putting It All Together

Pop the battery pack and LEDs inside the dome, turn on the power switch and turn off the lights!

(optional: wire up a DC motor with a platform and place the whole dome on it to make it spin.)