Bringing the stars to your baby

[Zach] saw a stuffed animal that projected some simple stars on the ceiling. This gave him an idea that he could build a tiny star projector for his 3 month old daughter’s room.  The idea is to put an LED inside a ping pong ball with tiny holes and rotate it slowly.

The electronics are fairly strait forward. He’s using an MSP430 to control the servo and LED, allowing him to set different speeds and turn the whole thing off after a certain amount of time.  The ball took a little bit of trial and error though. He first started by drilling some holes, but found this to give poor results. The holes were just too big. He finally ended up heating up a  sewing needle and melting tiny holes in the ping pong ball. That worked perfect.

After the break you can see a video of it moving. The servo is pretty loud, which might actually be a good distraction for a 3month old, but might be something to address in the future.

35 thoughts on “Bringing the stars to your baby

  1. so i read it all and definitely see room for improvement. first id try using a tiny insulin needle to poke the holes, definitely upgrade the led, instead of the servo use a small tape player motor or something similar so its alot quieter, and make up a better pattern for your holes. theres multiple websites you can find that have actual star maps you can print out, wrap around your ping pong ball and poke corresponding holes in. I realize this is just for a kids room but it would make a really cool living room piece in the dark too

  2. Okay
    That must be the worst jerky movement I’ve ever seen in one of these things! Is that just a test or something, cos you’ll only freak your kid out!
    For starters, wouldn’t it be better to alter the servo for continuous rotation and alter the speed between slow and, well, slower, then make it reverse direction occasionally.
    Even I, as a non-parent, can tell that smooth, slow motion would have the desired calming effect on the young’un.
    Also, how much are MSP430s, cos a small PIC chip can be had for less than a quid, and will control a single servo easily. Also, how about a PWM brightness control, adjusted randomly up and down for a further cool effect.

  3. It would be cool to print out a star map and do this on a slightly larger scale, but with a real map of the sky. Put the north star along the axis of rotation, angle it to match you current latitude, and you project is educational as well as fun to watch.

  4. In cleaning out mt mom’s garage last Spring I tossed an old kids record player. There being better record players around I couldn’t think of a reason as to why keep it, can’t keep everything forever. 33 & a turd might be to fast for this, but a record turn table may be a better starting point for modification.

  5. So that video was a waste of time. A ball jerkily moving left and right.

    Based on what the guy has said on his site, he had a problem capturing it on camera. That’s a shame but fair enough I guess.

    I like the general idea of this project but wonder if the result is really worth it considering how it looks compared to a commercially made $5 chinese made product.

  6. good idea, cool lighting effect.

    but about the motorization:

    i doubt a human baby would enjoy anything of the sort. because it needs to be:
    S L O W -ly moving… not slow-LY moving.

    remember newborns vomit 5 times a day for months…
    you ever enter a rotating room while slightly drunk and just TRY not vomiting! lol cant do it eh?

    in my opingion the dots of light on the walls need to advance ONE centimeter per minute, or less.

    it doesnt “need” to be quiet, it HAS to be quiet! absolutely!

    motors and gears are not soothing to babys, they are ONLY soothing to adults because we know the fridge ect is normal and good if its working properly it is doing it’s job and (electro-)mechanicly happy. :)

    happy fridge = happy wallet
    happy wallet = happy adult
    happy adult = sleepy adult (if bed time)

    but to a newborn BABY its a foregin and MONSTERy like noise!

    cats meow, birds chirp, and motors(&servos) go GRRR!!! lol

    absolutely no way i would start with a servo, not counting cost…

    servos are precision devices designed to deliver high torque. all you need is a (whimpy) whisper quiet geared motor…
    CD(-ROM) drive anybody? personally i got 2 broken / stripped ones and several in various states of disassambly ready.

    1. EDIT: as-is this creation is PERFECT for a social gathering of adults… and looks “trippy”…

      which may be the original intent XD ;)

      many inventions only need an excuse to exist, in order to obtain initial funding, then they rapidly become used for many things,
      electric motors; case in point.

  7. i like the idea, agree the motor choice is…lacking
    there are other options…hey use what ya got…but
    even a outlet timer i got at Canadian tire for 4$ is quiet and…slow like barely moving…can be re-geared easily to be a bit faster
    as far as a work in progress goes…everything starts with a prototype

  8. Wow some of you people are horrible!! Let the parent decide if it’s too loud or annoying to the their child!! I think it’s awesome that a dad would put together a project for their little ! one! Keep up the good work Dad!!

  9. And about the noise. I find the best (?) way to get my baby to stop crying is to turn on the kitchen fan. The noise makes them fall asleep almost instantly. I don’t think the noise of this motor would be bad… I’d see it as a benefit.

  10. they sell these really cheap at frys. and they have actual star formations on them. one is shaped like the death star too if you like that sort of thing. Why reinvent something thats been done and readily available?

    1. If nothing else, scratch-building objects which are already well-understood and readily available is an excellent learning experience for the builder. I know a guy who once said that he programs Conway’s Game of Life as a practice exercise whenever he wants to learn a new programming language.

      1. Also, for doing things with groups (Boy scouts, public maker events) finding super cheap alternatives to making stuff you can go out and buy is great. Instead of making something new that they dont understand, they can go.. “Holy crap I built a planetarium out of a ping pong ball!”

        These serve as great jumping off points. Pretty soon we are going to see someone getting a high power halogen light, lenses and a dog bowl making one.

        A year after that, maybe one you can buy and build as a kit.

  11. Great idea and pretty good implementation.

    “Why reinvent something thats been done and readily available?”

    ^ Not something we like to see here! Just because something exists doesn’t mean it shouldn’t be remade, improved upon, or made just for the hell of it!

    1. I’ve made more things than I can count; some were good and some not so good. But if something is made it’s because it fulfills a specific purpose that is not available from anything else. How about this…my next HAD is a new remote control for your tv. I call it pointy stick. Now you can see what I’m saying, right?

  12. In an effort to be productive….

    How about replacing the motor with a music box?

    Simple, wind-up, non electric, music box. Replace speed regulator (fan like thingy) with magnet/inductor to power LEDs,

  13. I like the idea. I like the quieter motor comments too. But I can see the noise helping. If it jerks around, but have a constant “sleep” time, you have a make shift metronome. When I was growing up, my parents gave me a wrist watch to sleep with. The ticking was my friend and kept the monsters away lol.

    I also like the idea of using a blue LED.

  14. I think I would have used a dc motor with a rubber wheel then cut out a large circular base out of wood maybe and pressed the motor up against the edge of the circle to make it slowly turn

  15. Time Tip:
    Instead of heating a sewing needle, making a hole and then reheating the needle to make another hole, burning your finger, then repeating…

    Load the sewing needle into a dremel, just like a drill bit. I did this to make holes in polypropelene tubing and it’s super-effective.

  16. My daughter has a variation of this, but there is no motor or servo. Instead, the light/heat first runs through a transparent “windmill” wheel that’s also attached to the projection cylinder and the rising heat from the bulb rotates the whole thing.

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