Shadow Separator, a Knex Ball Machine Path Separator

About: Hey! I'm Sandroknexmaster. I like building with knex, especially ball machines. I live in Belgium. I speak Dutch, but also English and French. I hope you like my stuff, and like always comment, rate &...
Hello knexers!

Here are the instructions for the Shadow Separator, first seen in my knex ball machine Paradox.
This is the last part from Paradox, now the instructions for all the new elements/lifts/separators are online.

The Shadow Separator is a complex, piece consuming separator with a self-resetting mechanism.
If you don't want to spend too many pieces to a separator, I suggest that you just watch and don't build (It would still be nice if you did so :D), if you have some pieces left and don't mind using them in a separator, this is the perfect instructable for you!

About the name... I'm sure you're wondering why this is called the Shadow Separator.
I did not invent the self-resetting mechanism myself, it is Shadowman39's invention (You can find the original instructions here).
So a lot of credit goes to him, without his mechanism this separator wouldn't exist.
And to give even more credit (and because it sounds awesome :D), I called it the Shadow Separator.

I hope you like this separator, tell me what you think about it in the comments.

If you build this separator, please read every image note. They will help you a lot!
A problem? Questions? Feel free to comment or PM me.

Thanks for watching / building!



Step 1: Piece Count

If you want you can count the pieces before you start building.
Here is a list with all pieces included in this separator, named by their original color:


Green: 138
White: 82
Blue: 129
Yellow: 35
Red: 23
Grey: 1

Total rods: 408


Dark-grey: 40
Light-grey: 18
Orange: 26
Red: 69
Green: 11
Yellow: 84
White: 7
Purple: 102
Blue: 14

Total connectors: 371


Blue spacer: 41
Silver spacer: 38
Y-clip: 39
Tan clip: 8
Blue clip: 3
Blue hinge: 3
Black hinge: 3
Small hub: 1
Small tire: 1
Small blue gear: 1
Medium yellow gear: 1
Motor: 1

Total other: 140

Grand Total: 919

Step 2: Self-resetting Mechanism Part 1

The first part of the self-resetting mechanism, there are 3 parts in total.

Step 3: Self-resetting Mechanism Part 2

The second part of the self-resetting mechanism.

Step 4: Self-resetting Mechanism Part 3

The third and last part of the self-resetting mechanism. In this step you will also be testing it.

Step 5: Staircase Exit

In this step we're going to build 4 of the 6 exits.

Step 6: Separator

In this part, the balls get separated. Be sure to build everything exactly as you see it, or it wont work.

Step 7: Arm

This arm will start the motor, and lift the last ball up so it can reset the machine.

Step 8: Return Track

The last ball will roll on this track after it is lifted up by the arm. As it rolls down, it will help resetting the mechanism.

Step 9: Entrance

The last step! The entrance, where everything begins.

Step 10: Finished!

The Shadow Separator is finished!
When you have finished your own Shadow Separator, you can send me a picture so I can add it to this last step.

Thanks for watching / building!




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    44 Discussions


    3 years ago on Introduction

    This thing is amazing and works pretty well. But I have a pretty major problem. When all the switching modules are down and I put down another one to make it reset, the motor doesn't start. I had the same problem when I built the leave me alone box. Any suggestions?

    4 replies

    Reply 3 years ago

    If you're sure you've built it correctly, then I don't really know what could be the problem. Maybe try to mod it a bit yourself?


    Reply 3 years ago

    well, when I put the separator to the base I heard something snap, so... maybe rebuild it? I don't know any other way. Anyway, it was fun to build and it's cool, so I'll try again. ;)


    4 years ago

    It's ok, I modified it,
    The only problem is that the little lever that goes up does not reset back down, but it works about 95% of the time

    1 reply


    Yeah it's a bit complicated, there are probably better ways to make a separator that functions the same. So if you want to give it a try ;)


    4 years ago

    I just built it,
    But the ball has trouble getting from the arm to the higher platform

    15, 8:08 AM.jpg
    1 reply

    WOW, It's Great! Unfortunately I'm not so good at building balmachines ... I can't wait for you next instructable :) (sorry for bad English)

    1 reply

    5 years ago on Introduction

    How did I miss this!?!?! A very cool seperator Sandro, I like how it resets itself. A neat mechanism.

    1 reply