How to Make a Star Projector





Introduction: How to Make a Star Projector

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

- 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 (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.

- 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.

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.)



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    14 Discussions


    Question 5 weeks ago

    Great project! I was just wondering, are the stars/holes random or are they from a star map? Thanks.

    I would really love to make this! I followed the link to the LED board you used, and they are discontinued. Any suggestions for an alternative? Thanks!

    1 reply

    A local sign shop would prob be willing to sell you a few ultra bright LEDs... They might even have some old discontimued ones you could have :) never hurts to ask.

    what kind of paper that you use ?

    u can literally just get a can and poke holes in it and put a candles or a light inside of it. BOOM !! literally only 5 dollars

    1 reply

    Hi, I'm a beginner when it comes to just about DIY-anything. I notice one of the necessary tools for this project is a "laser cutter". Is this something average people have in their craft room, or is this project for more advanced DIYers than I?

    1 reply

    I'm pretty sure the average person doesn't have a laser cutter in their craft room. Laser cutters run from a few hundreds of dollars to a few thousands depending on quality and power, meaning they're a huge investment and really expensive if used for only one or two projects. However, there are some companies that will lasercut parts for you and even others that have locations where you can use their laser cutter yourself. That being said, laser cutters aren't always an absolute necessity. While they may be invaluable in projects requiring precision and uniformity, I think there are a lot of cases where you could do without one. In this project, for example, you could always hand-cut the pieces and drill the holes yourself. The pieces might not fit together as well and it'd take more time, but it's definitely possible.

    Nice Instructable! About the electronics, though... with three 470ohm resistors and one 4.7ohm, around 97% of the current is going to pass through the 4.7ohm, making the other three superfluous.

    Two pairs of 4.7ohm resistors wired series-parallel would give exactly 4.7ohms (tolerances aside) and split the current and power evenly. However, you'd still need high-power resistors and waste a lot of power and battery life generating heat. A simple constant-current source (can be just a NPN transister, an N-FET, and two resistors) would be better, or even an integrated switching current source like the LED2000DR ($2/ea. at Digikey, plus a few discrete components). Minimizing the difference between the battery voltage and the LED voltage drop also helps.

    Oh, Home Depot sells a 24V DC transformer, that is usually used for a wired doorbell. The 21V DC motor can run off that, but you have to wire the transformer to run off a wall outlet.

    An AC turntable motor from a microwave oven would be perfect for the turn table. Very torquey and compact. Read the lable, though. Some of them are 21V DC.

    Hey there. Love the idea, it is definitely going to be a crucial part of our spacement project. We have made the star shell part and had to scale it down a bit to fit on a print out that I used but seems that it should still work. Our biggest hangup right now is the lighting. We aren't familiar with soldering and were wondering if you had other ideas for how to get it to be bright and crisp like yours. We tried a high watt light bulb and that doesn't do the trick and the "stars" are not sharp. Any thoughts would be much appreciated, thanks!!

    Hi Audrey,

    Thanks! That first picture is one taken with the projector in my room. The LEDs listed are pretty bright. It easily reaches the 10 ft ceiling from the floor. This was created for a presentation in an auditorium and did a good job at it.
    I just don't have a camera with a good enough sensor to capture the real light quality, just an iPhone photo. Hope that helps for reference.