Picture of Programmable Knex Piano-Playing Robot
I've always been a big fan of K'nex, ever since I was a little kid. Then, when I discovered this website, I felt like I had hit the jackpot. This is a "robot" that I built out of knex, it's designed to play the piano. This version can play up to a 16 note sequence in a 12 note range. I call it "Zeeanobot" (Zach's Piano Robot), corny, I know, but I couldn't think of a better name. I spent a lot of time on this, and I'm very proud of it, so please be nice. Just to be clear, I have not tried it on a real piano, I built it to play my Yamaha DGX-230. You may need to modify the design slightly to get it to work on real pianos or other keyboards.

Please note that this is my first real instructable, so I'd appreciate any constructive criticism. Thanks. (So far the response has been mostly positive, so thanks everybody! I put a lot of work into designing and building this so I'm very proud of it. I'm glad you like it too.)

The first video is a mechanical view of Zeeanobot, showing how it works.

The second video is Zeeanobot playing a simple proof of concept song.

The third video is a duet of Katy Perry's "Hot and Cold". Ignore the errors on my part, they're not the point.

The final video is a duet of "Heart and Soul".

Step 1: Materials

Picture of Materials
Materials Required:


6 x Black Rods
25 x White Rods
100 x Blue Rods
104 x Yellow Rods
23 x Gray Rods


20 x Gray 1-Prongs
60 x Gray 2-Prongs
4 x Brown 2-Prongs
41 x Red 3-Prongs
28 x Interlocking Gray 4-Prongs
1 x Green 4-Prongs
54 x Yellow 5-Prongs
20 x Interlocking Blue 7-Prongs
18 x White 8-Prongs


63 x Blue Spacers
48 x Gray Spacers
2 x Small Blue Gears
8 x Medium Red Gears
2 x Big Black Gears
48 x Chain Links
37 x Tan Clips
1 x Motor
1 x Piano (Optional)
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Haha now I don't have to do piano anymore!!!!
KGuy3 years ago
I'm probably the first comment you've had in a while.........................................can you use the smaller chain links? I'm all out of regular.
And that is realated to this instructable in which way other than its knex?
It makes noise?
S'pose so…
Still pretty unrelated :^/
if u trow a real grenade at them i bet they both explode XD
Superben513 years ago
am i the only one kidda scared about this?
~KnexBuild~3 years ago
Cool Mech, 5 stars
hunter9994 years ago
It is very good u should be proud, may i ask how long did it take to make
plysaxaphone (author)  hunter9994 years ago
It's hard to say. I worked on it a little bit at a time over the course of several months. But thanks, I am proud of it.
I'm going to try and make it (a modified design) in under 48 hours, I think i can.
brammeke115 years ago
 Sry for the double post but do you play the saxophone?
plysaxaphone (author)  brammeke115 years ago
Yes I do, as well as the piano and the viola.
Viola?! Nice

I play the sax to. I have have alt, tenor and a bari. =D
 Bassoon!!!!! get some!!!!

99igo Azayles4 years ago
finaly a cool instrument i play
ajleece4 years ago
I really like this! I want one!
If only it was a bit more in time.. Haha
rustymia5 years ago
i would like to build this exept i only have 6 red gears do you no any way i could make it work? Great instructable 5*
plysaxaphone (author)  rustymia5 years ago
You can build just one of the modules(hands), but you'll only have a 6 note range. To do that you only need 4 red gears.
joey995 years ago
were are the videos?
Bartboy5 years ago
 Can I suggest re-designing it so that it uses gears with chains on them for the programming? That would allow much more complex rhythms 
plysaxaphone (author)  Bartboy5 years ago
Its funny that you say that, I spent a lot of time trying to use gears and chains as a means of programming, I just couldn't make it work. I'm sure someone will improve on my design sooner or later, and maybe they'll figure out how to make it able to perform longer sequences. I sure hope so.
 Look at my other comment, I managed to program a knex robot using a chain 
plysaxaphone (author)  TheFoofinator5 years ago
Yea, no doubt yours is cool, and a good design. However, you really couldn't apply it to my robot, well maybe you could, but I don't see how without major modifications.
I did make one that could write, with two chain units for up/down left/right. It sort of worked, but the writing was unreadable.
 You got that Idea from mine! >:(
wertywaster5 years ago
rexdino55 years ago
This is very awesome! It is one of the best K'nex models I have seen.
Merugop5 years ago
 Brilliant just Brilliant 5* dude i sub too. 
arrow shot5 years ago

Yeah, I found it similar to music box mechanics. I might actually build this if i can find the pieces, this is the most genius knex build ever, very unique too. Not just another gun or rollercoaster, ball machine etc, this is epic.
kelseymh5 years ago
I don't know why, but the videos are not being embeded on the page I'm viewing.  This is not your problem; I just wanted to let you know.

Other than that, this is probably the best K'nex Instructable, and one of the best Instructables of any kind, that I've seen.  You actually wrote out how to construct the components!  You used proper English!  You've got clear pictures!  And the project itself is just, well, I'm stunned.
It's not the first knex instructable with clear pictures, proper english, and "how to construct the components".
Didn't say it was the first, but it is the first that "I've seen."  Which includes the obvious qualification that it's the first I have looked through with those qualities, having the obvious requirement that the topic has to be interesting enough.  The card shuffler, for example, was a cool project, but not as well documented.
I saw that the parts of the card shuffler were somewhat disassembled while here he just dissects it into chunks kind of like what I do, and doesn't disassemble it if it's too inconvenient.  I don't think a first time knexer could build this just from what he has.  I could, but that's a different story. 

I'm not ripping on his ible, but I don't see how the card shuffler wasn't as well documented as this.  Or I might be missing something from your point of view.
The card shuffler's "documentation" was only in the form of image notes.  Those are not accessible, not printable on steps, and cannot be viewed at the same time as the image (since they get in the way).
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