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".

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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!!!!
KGuy2 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.
KILLERK4 years ago
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
27ace275 years ago
(removed by author or community request)
 Guess what my two favourite hobbies are? Teh same ones as yours!  I have a mamod sp4 and  the mamod car (in green), my sp4's piston exploded in my brother's face it was the funniest reaction I have ever seen in my life!
Cool! lol, so the piston literally exploded, or did it just shoot off?
 Well it popped off, but the crank rod snapped in half because it was still attached to the crank
oh dear! I trust it works now?
 Yep just bought a new crank rod and bolted the cylinder bak on
nice! BTW, be on the looks out for the knex lemonade machine MKIII, preliminary tests are all good!
David97 27ace273 years ago
I am acualy building a steam engine myself. it teams to have alot of power for a boiler that size. What is the size of the cylinder?
Is that steam powered? The piano player work basic the same way the chimes on a Grandfather Clock do. I have to agree that  K'nexs are great for build mechanical things. I have made a drag saw, a crawler, and model of an internal combustion engine, a pendulum clock, and a distrubuter.
(removed by author or community request)
Where did you get the steam engine?
Ebay! I get all of my engines from ebay. here is my website showing most of my engines; chack back more during the summer as I will do some major updating.
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
rustymia4 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)  rustymia4 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.
joey994 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.
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