K'nex Ball Counter





Introduction: K'nex Ball Counter

About: I make K'nex Ball Machines. Here you'll find instructions for some of my simpler projects and photo diaries of my more complex machines. I'm still in the process of building a ball machine larger than any be...

Hi everyone,

This is my newest K'nex creation, a motorized mechanical K'nex ball counter which is part of my up and coming ball machine. I am planning to use it to count the number of balls going down a certain path on the machine which will also be the number of times the main lift goes up and down.

How it works:

It has 1 regular K'nex green motor that powers the 2 counting dials. It is turned on when the ball falls down a chute and lands on a switch starting the motor. The motor turns a series of gears which turns a small arm turning the units dial 1/10th of the way round. There is a blue clip on one side of the dial so that every time the dial switches from 9 to 0 it lifts another arm which is attached to a gear. This gear meshes with a gear turned by the motor and then using the motors power turns another small arm which turns the tens column. This gear then resets until it is turned again to mesh. The machine then also turns itself off after one complete circuit using a design created by shadowman39 that I have modified so credits to him.

Some stats:

  • It took around 15 hours to design and construct over a period of about 3 weeks.
  • Uses approximately 2,000-3,000 classic K'nex pieces
  • 245 of those pieces are used in the dials
  • The dimensions are 1 red rod high by 1 red rod deep by 1 1/2 red rods wide (3 blue rods) so 128x128x180mm

Any questions feel free to ask I hope you enjoy it ;)

-Northern Fields-

Step 1: Some More Photos...

Step 2: Prototypes and Dial Design

Just a few more pictures showing some of the designs before I added it to the ball machine and how I made the dials



    • Stick It! Contest

      Stick It! Contest
    • Oil Contest

      Oil Contest
    • Game Life Contest

      Game Life Contest

    19 Discussions

    Wow, nice job! This is what instructables needs, stuff like this that is complicated, interesting, and creative ;D

    2 replies

    Thanks I really want to post proper step by step instructions for it but I think its too complicated for that so many fiddly fine tuned bits XD Thank you hopefully more like this to come ;)

    Ah, I understand. It DOES look really complex. But, anyways, great job!


    2 years ago

    That's brilliant.

    Two things:

    1) It's difficult to see from the photos exactly how you have made the reels. Any chance of some more close-up photos?

    2) How have you switched the motor on and off?

    1 reply

    If you view all the steps under prototypes and dial design there are some close up pics of the reels. :)

    The ball hits a green connector switch which then turns the motor switch, turning it on. Then it automatically turns off using a mechanism I designed so it's ready for the next ball. It doesn't complete a circuit to turn the motor on it just uses the switch built in already to the green knex motors.

    No problem! Yeah I don't habe a lot time, but I will try to post instructions as soon as possible (I don't know when that will be though)

    Thanks, I like 3xodus as well I think you have a lot of potential to make some great bms :)

    wow thank you ;) it means alot to hear that people like my creations and that I have potential :D

    Haha your welcome you seem enthusiastic about K'nex and I see that you have a lot of ideas. Just keep innovating :)

    don't worry I will :) my next ible will be my Spinny element in 3xodus the one in path 1 at the end. :)

    Ah I look forward to seeing it and all the other ibles to come :D

    Ah I look forward to seeing it and all the other ibles to come :D

    WOWWW that is just amazing i never see a knex counter before (only the shadowman s point counter) but i would like instructions so bad but its hard ... and i under stand you i need this counter on my second ball machine :-(

    2 replies

    and i don t know how the second gear (the second numbers like 10 20 30 40...)works.

    i think the mechanism is soooo awesome

    thanks :D yh idk how id really make instructions for this its so complicated and really hard to get it to work right :/ I may after the finished bm give instructions on how to build separate bits like the dial and moor switch?

    Well the first gear when it switches from 9 to 0 also turns a rod which makes a gear turn (the yellow one). The gear meshes with the other motor gears (The grey ones) and so then that whole rod is powered by the motor. So then there's another arm on that rod that turns the tens column so it can go from 9 to 10 and 19 to 20 etc I hope this helps it all happens sumultaneously so it's hard to explain :/