r/arduino • u/MegCell • 21d ago

Project Update! I built an Arduino-controlled robot that physically plays a real guitar

Quick update on my guitar robot project.

This is a multi-camera recording of it physically playing “Hotel California” on a real guitar.

Still refining the mechanics and control, but it’s getting much closer to the level I originally wanted.

712 Upvotes

99% Upvoted

84 comments sorted by

44

u/Matthijs2101 20d ago

wow, would be cool the have in my living room. just playing out some music instead of spotify.

7

u/MegCell 19d ago

Exactly！Spotify plays the recording — this lets the actual guitar play in your living room.

21

u/h11ywdshufle 21d ago

Thats crazy! This is awesome!

2

u/MegCell 19d ago

Thank you!! Really glad you liked it!

2

u/h11ywdshufle 19d ago

I do, just hope I can get this good one day! Keep up the good work

14

u/Snoo23533 20d ago

I saw another person do this but their servos were as noisy as the guitar itself. Is this audio filtered?

4

u/MegCell 19d ago

No, the audio isn’t filtered. The servos are still audible, but this version uses quieter bus servos, so the mechanical noise is much lower. I’ve tested cheaper servos too, and the difference in noise is huge.

3

u/dbu8554 20d ago

I dunno about that guy but just use quieter servos like I'm trying to imagine small servos as loud as a guitar.

7

u/boulderingfanatix 20d ago

Great haunted house addition

3

u/MegCell 19d ago

That actually sounds like a great use case Perfect for a haunted house.

5

u/doge_lady 600K 20d ago

Can it do a legato slide?

2

u/MegCell 19d ago

Not yet 😄 Hammer-ons and pull-offs work, but a proper slide still needs more mechanical development.

5

u/world_admin 20d ago

This is very impressive work. What about the mechanics, 3D printed?

2

u/MegCell 19d ago

Thanks! Yes, most of the mechanics are 3D printed, with servos handling the fretting and picking. TPU is used on the contact points to protect the guitar.

2

u/world_admin 10d ago

Outstanding!

5

u/SumoNinja92 20d ago

Physical Midi sounds crazy

2

u/MegCell 19d ago

“Physical MIDI” is actually a pretty good way to describe it. Except the sound is coming from a real guitar.

2

u/SumoNinja92 19d ago

That's what I mean, it still has the short disjointed sound of midi but IRL.

3

u/Current_Payment_2988 20d ago

Damn that’s awesome i need one

3

u/MegCell 19d ago

Thanks! 😄 You actually can — the DIY version is live now at meg-cell.com.

3

u/MrJdaddy 20d ago

Very cool!

2

u/JohnnyGoGo_0414 20d ago edited 18d ago

Science is elegant.

1

u/MegCell 19d ago

Thank you! I love it when engineering becomes part of the art.

2

u/MakesShitUp4Fun 20d ago

Great job

1

u/MegCell 19d ago

Thank you!

2

u/Comfortable_Ad_7015 20d ago

Não sei, algo soa estranho.

1

u/MegCell 19d ago

Fair enough, There are still some timing and articulation details I’m working on.

2

u/Liquid_Magic 20d ago

If you released this as open-source on github that would be awesome!

2

u/MegCell 19d ago

I’ve thought about it. As a solo developer, the time and cost are pretty significant, so for now I’m selling a DIY version to help fund continued development. I may open-source some parts later on.

2

u/Liquid_Magic 19d ago

Fair enough! Very cool!

2

u/Azsde 20d ago

It sounds like a midi track ! Awesome project :)

1

u/MegCell 19d ago

Thanks! It is very precise right now, maybe a little too precise. I’m still working on dynamics, timing, and articulation to make it feel more natural.

2

u/grantrules 20d ago

Now do Classical Gas!

1

u/MegCell 19d ago

Great suggestion Classical Gas would be a perfect test for speed, articulation, and dynamics. Added to the challenge list!

2

u/grantrules 19d ago

Should def start with Lisa's union strike song tho

2

u/Probably-Stable 18d ago

What!?!?! Dude

1

u/Longjumping-Knee2469 20d ago

That’s pretty dope, but can it flat pick?

1

u/MegCell 19d ago

Yes, The picking unit uses replaceable picks, and softer flexible materials can be used as well. That lets me tune the attack, noise, and feel for different playing styles.

1

u/Longjumping-Knee2469 19d ago

Cause I’d be very interested in seeing it do a black mountain rag or a turmoil and tinfoil the artist is Billy strings I really like what you’ve created just is always fun to push things to its limit

1

u/MegCell 19d ago

I’d love to try those eventually 😄 but the current version probably isn’t quite there yet. Right now the practical speed limit is around 400 BPM, and very fast flatpicking also puts a lot of demand on cross-string timing and articulation. Still a good target for future testing though.

1

u/Longjumping-Knee2469 19d ago

Please let me know once you get there what you’ve created is pretty awesome and I do. Thank you for sharing.

1

u/MegCell 19d ago

Thank you, I really appreciate it! I’ll definitely share an update when I get it there.

1

u/imbuildingshi 20d ago

That’s sick bro

1

u/MegCell 19d ago

Thanks bro! Really glad you liked it.

1

u/Aggressive-Art-9899 20d ago

I welcome our new musical overlords.

1

u/MegCell 19d ago

Thank you 😂 The musical robot uprising has begun.

1

u/eddylf 20d ago

Hotel California is indeed an All-time classic but for a moment I thought you were doing an Animusic homage. I think it would be quite fitting.

The mechanisms are awesome and work perfectly!

2

u/MegCell 19d ago

Thank you! Animusic is actually a very fitting comparison — turning music into something physical is exactly the direction I’m interested in.

1

u/Tuesday2017 20d ago

Very cool!

How is it pressing down the strings ? Can you show a camera angle for that ?

Also I have a song request - Eruption!!

2

u/MegCell 19d ago

Thanks! The strings are physically pressed onto the frets by servo-driven actuators. I’ll try to show a closer fretting-angle video next time.
Eruption is definitely on the “challenge list” Hammer-ons and pull-offs work, but the current version still can’t do everything that song needs.

1

u/Janoschhu 20d ago

POV: you cant play guitar, but u can programm. I love it real hard

1

u/MegCell 19d ago

Haha, pretty much 😂 If I can’t play it well enough, I’ll just engineer my way around it.

1

u/Penguin-a-Tron 20d ago

This is pretty fantastic. How is the music encoded- MIDI files or something else? Do you have a write-up of how it works anywhere? I'd be very interested to read.

2

u/MegCell 19d ago

Thanks! Right now the system mainly reads MusicXML, not MIDI. The software converts the score into the timing, fretting, and picking commands that physically play the guitar.
I don’t have a full technical write-up published yet, but I’m gradually putting together more documentation and videos. I also have a DIY package available now, which includes the 3D-print files, controller software, ESP32 firmware, activation code, and assembly guide if you want to dig into how the system is built.
It’s available at meg-cell.com.

1

u/relaqz 20d ago

Awesome!

1

u/MegCell 19d ago

Thanks! Really glad you like it.

1

u/retrorays 20d ago

Very cool

1

u/MegCell 19d ago

Thank you

1

u/onlydaathisreal 20d ago

This is cool. Reminds me of the band Captured by Robots!

1

u/MegCell 19d ago

I’ll have to check them out. A full robot band is definitely a direction I’d love to explore someday.

1

u/rickyzhang82 20d ago

This is dope!

1

u/MegCell 19d ago

Thanks! Glad you think so!

1

u/xXKarmaKillsXx 19d ago

Pretty cool. Just need to add ai.

1

u/MegCell 19d ago

Definitely. AI can handle the composition or arrangement, and MegCell can turn it back into physical music on a real guitar.

1

u/ExJwKiwi 19d ago

How does it work? Doesn't appear to press down on any frets, just picking strings?

2

u/MegCell 19d ago

It actually has two systems: one for picking and one for fretting. The fret actuators physically press the strings down on the neck, but that part is mostly hidden from this camera angle. I’ll film a close-up of it next time.

1

u/AtmosphereVirtual254 19d ago

It’s surprised me multiple times how complicated the digital version of this is

2

u/MegCell 19d ago

Exactly, I thought the mechanics would be the hard part, but the software and timing became a whole project on their own.

1

u/DiggoryDug 18d ago

Very cool. Why do the 'pickers' need to move vertically?

1

u/commodore_vic_20 18d ago

Bravo! Bravo! Well done. Might need to add that to my to-do list. Very cool.

1

u/MegCell 18d ago

Thank you! If you end up building something similar, I’d love to see it.

1

u/Ok_Leg_109 17d ago

Really great work.

If you ever plan to do a V2, you might want to look at the design of the "jack" in a harpischord.

I might simplify the picking because it only needs vertical motion. Volume is controlled by how far the Plectrum is slid under the string.

1

u/IshakA17 17d ago

Un robot tocando mejor que yo

2

u/MegCell 17d ago

Haha, I’m still teaching it 😄

1

u/AbbreviationsNeat837 17d ago

how the HELL. did you do that

1

u/MegCell 17d ago

Years of trial and error, a lot of redesigning, and plenty of help from AI along the way 😄

1

u/enhancedbeautylover 16d ago

Really impressive 👍. How long time did it approximately take you to design and build this marvel?

1

u/MegCell 15d ago

Thank you! It’s been about 6 years of part-time development — mostly evenings and spare time, with a lot of testing, redesigning, and starting over along the way.

1

u/paperbag005 14d ago

This is so cool! Im new to this, so I was wondering how youve added the chords to hotel California to the arduino. Have you manually coded the servo movements for each chord for the entire song or is there some other way? Also wpuld love to know the general mechanics of this , so please link the git if youve made one !

2

u/MegCell 13d ago

Thanks! I don’t manually hard-code every chord and servo movement for the whole song. The system reads a MusicXML score, processes the notes/chords, converts them into fret and picking actions, and then sends the timing/control data to the ESP32.
So the workflow is more like: MusicXML → note/chord processing → servo actions → ESP32 playback.
I haven’t open-sourced the full project on GitHub. Right now I’m offering it as a DIY package, which includes the 3D-print files, ESP32 firmware, PC control software, activation code, and assembly documentation. If you’re interested, you can check meg-cell.com.

0

u/Victory-Scholar 15d ago

That's so precise. Very good work.

Would you mind writing a detailed article or preparing a video to explain the things in detail?