Connect with us

Beginner project - rotating motor?

Discussion in 'Sensors and Actuators' started by Crumbs, Feb 17, 2014.

Scroll to continue with content
  1. Crumbs

    Crumbs

    4
    0
    Feb 17, 2014
    Hey,

    First of all I'd like to confess that I really have no electronics background, so I have no idea about anything in this field.
    For a friend's birthday, I have bought the Kikkerland Music Box DIY Kit, which lets you punch holes in a music strip, which the accompanied music box plays. However, this "music box" works by manually turning the small lever, you can see a photo of how it looks here:
    https://www.kikkerland.com/products/make-your-own-music-box-kit/

    What I would very much like to do is somehow make it turn "on its own", i.e. without my friend having to turn thr lever continuously each time they would like to hear the music.

    The only thing I could think of is to get one of those small simple motors, and attach a "lever" to it so that it will spin the music box lever. However, from what I know these motors spin very fast, and the music box lever needs to be spinned pretty slowly (imagine as if you're turning it with your hands, it's not that fast.

    So as you see I have no idae what I'm doing, but this is very important to me and I would really like to find a solution. This means I need to find a solution that will turn the lever in a normal speed - a speed that I cannot define, so it would be great if I could play with it until it is just right. You can see an example of the speed needed in this video (05:10 mark):

    However it could be a bit slower I guess.

    I would really appreciate anyone's help in this matter.
    Thanks!
     
  2. donkey

    donkey

    1,300
    56
    Feb 26, 2011
    ok here comes the fun part,
    first remove the small lever
    install a DC motor with same shaft size
    connect dc motor to batteries, if it turns the wrong way connect batteries other way around
    that is the basics
    now you will want to control speed this can be done a few ways, first is to lower the volts used(less batteries)
    the second is buy a cheap PWM kit of ebay that controls the speed of the motor
    last and most inefficient way is to chuck a resistor or potentiometer in there. if you want small go with 1st or 3rd option. if you seek to impress go with PWM and that will also save some battery life.
    the last thing that you could do involves next to no electronics know how, its called a gear box, any decent hobby shop will have one of these but getting the right ratio will take a lot of work I am assuming you are looking at about 30 turns per minute so there's a start.
    the PWM method is simple and you can control it. a kit for these will sometimes have screw terminals so all you need is a screw driver no soldering needed. hope this helps
     
  3. Crumbs

    Crumbs

    4
    0
    Feb 17, 2014
    Thanks donkey, that helps very much. It doesn't seem possible to remove the lever (it's pretty much built-in, without screws etc.), but I think I can find a way to stick something onto the engine so that it will turn the lever (if it has enough torque). I will also check out the option of a suitable gear box. Thanks again, this indeed has got me on some track, at least I know what to look for now in the store.
     
  4. shumifan50

    shumifan50

    582
    58
    Jan 16, 2014
    It looks like about 120 revolutions per minute is needed by my count.

    Look here for motors:
    120 rpm motors

    I think they are a bit of an overkill, but there is quite a selection rated for different voltages.

    You will need to get some gears to do it properly:
    Plastic gears

    And the motor will need mounting somewhere.
    It will be best if you cut off the kinked bit of the handle, leaving a straight shaft.

    Instead of gears, depending on how hard it is to turn the handle, you can use plastic/rubber tubing from the motor to music box. The tubing has to fit tightly over the motor and the music box shafts. This is more forgiving as the motor and shaft does not have to be aligned perfectly.

    You could also buy a motor speed control from the same link for gears above, which will allow adjustment of the speed, if my estimation is wrong.

    Enjoy:)
     
    Last edited: Feb 17, 2014
  5. Crumbs

    Crumbs

    4
    0
    Feb 17, 2014
    Thanks shumifan50, that's a great help. The music box uses similar gears, so I can maybe bypass handling the lever and connect the engine+gear to the gears themselves. Anyway it seems I have several ways to go about this, I think I will visit a few stores around me and see what I can get locally, before trying to order these online which won't be ideal considering the trial-and-error nature of this endevor :)
    Thanks!
     
  6. shumifan50

    shumifan50

    582
    58
    Jan 16, 2014
    It does not have to be trial and error.

    1. Establish exactly how many revolutions per minute you need by turning it at the correct speed. Count the number of turns you complete in a minute. This tells you what speed the motor has to turn. Do this a few times and take the average. This will give you the speed of the geared motor you need. Any motor will do, the cheaper the smaller they are (typically) and I would guess that any of the geared variations will do the job. In this project accuracy is not that critical, because different people will crank at different speeds anyway.

    2.
    It is most likely easier to use a tubing drive, rather than a gear drive because gears have to mesh very accurately. Tubing allows quite a margin of error and also more flexibilty in where you mount the motor.

    A more professional connection can be made using a coupler:
    Couplers

    3.
    Speed controllers:
    Motor speed controllers

    I would buy the stuff of the web from the more reputable companies (like technobots), so returns are easy if needed, however, you do pay a bit more.
     
  7. shumifan50

    shumifan50

    582
    58
    Jan 16, 2014
    The link I gave to motors is ebay and most of those are from China. Delivery is about 3 weeks when I ordered. They are quite cheap. Technobots also sell motors, but they are quite a bit more expensive for the same thing.
     
  8. Crumbs

    Crumbs

    4
    0
    Feb 17, 2014
    Yeah you're right about the accuracy. I will tomorrow check out the local supply and probably end up ordering online :)
    Thanks for all the help!
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-