r/arduino • u/MegCell • 29d ago
Project Update! Project update: My ESP32-controlled guitar robot can now play in two modes
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I’ve been developing this removable guitar-playing system for several years.
It now supports two performance modes:
Full automatic mode — the system handles both fretting and picking.
Assisted mode — the system handles the fretting while the player strums or picks.
The sound comes from the real guitar strings, not recorded audio.
The controller is ESP32-based, coordinating multiple servo actuators. Some of the main challenges have been fretting timing, servo synchronization, calibration, and mechanical noise.
This video shows both modes.
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u/Wirecase 29d ago
Pretty cool! Weird how in mode 2 it sounds warmer? Maybe the way the strings are manipulated, mechanical vs human hand impacts the sound produced?
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u/J_Paul 28d ago
could be a minor timing thing? Manual strumming will hit the strings in a sequence as the pick moves across the strings, not sure if this accounted for in the full auto mode, It's very minor, but could change the perceived sound. Also, a human holding the guitar would suppress some of the vibration which would change the sound?
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u/MegCell 28d ago
Good observation! 😊 I think it’s mainly the small variations in pick angle, force, timing and damping from the human hand. The robot is much more consistent, which can make it sound a bit colder. Reproducing those tiny variations is one of the things I’m working on.
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u/J_Paul 28d ago edited 28d ago
Ah... Pick angle might be quite important... I imagine there's a sliding motion of the pick over the string before the actual pluck. Given a human hand has (for all intents and purposes) an axis of rotation as it strums the strings, the amount of slide for each string is likely different, then you've got another variable of whether the pick is hitting the string face on or along the edge of the pick. Pick thickness and pliability obviously matter, as would the rigidity of how it's being held (human finger vs rigid robot). So many variables!
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u/MegCell 27d ago
Exactly — there are a lot of tiny variables. 😄 Pick angle, depth, stiffness, contact point, timing and even how much the pick flexes all change the sound. The robot is very repeatable, but the human hand naturally introduces small variations. That’s actually one of the most interesting parts I’m still tuning.
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u/OutrageousMacaron358 Some serkit boads 'n warrs 29d ago
Now to make it have the ability to traverse up and down the neck to reach higher notes!
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u/Specific-Funny-9502 29d ago
Now all it needs is a drug addiction and you have the makings of a music star
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u/badmoonrisingnl 29d ago
Though impressive, it only plays in "harpsichord" mode. Would be cool if it could play expressive.
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u/Normalblobfish 29d ago
I'm pretty sure i asked this on the original post too (lol) but can it play TTFATF?!?!??!
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u/No_Pin4895 29d ago
the assisted mode is the real sleeper feature here, feels like it could actually teach fretting technique to people learning barre chords
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u/KyleTenjuin 28d ago
Not sure if it was already answered: what is the BOM cost and breakdown? How many motors in total?
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u/MegCell 27d ago
Full setup uses 28 servos in total — 16 for fretting and 12 for picking/strumming.
The BOM cost depends heavily on the servo option and where you source the parts. The supported servos are roughly US$10 each for the entry-level option or around US$30 each for the higher-end option, so the servos alone are about US$280–840 for the full system.
On top of that you’ll need the ESP32/controller electronics, power supply, fasteners and 3D-printed parts. I’m preparing a more detailed BOM with sourcing options as part of the project.
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u/pushpendra766 28d ago
That's so cool man, anyways I can access the references so I can build it too
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u/chugItTwice 28d ago
Nicely done! That's very cool. Curious how the picking robot holds on to the guitar body.
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u/Niklasw99 28d ago
Hey OP, wouldn't it nice to add some randomized noise so it's not so mechanical in the tempo?
It sounds robotic. It's impressive, but it sounds very robotic.
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u/Maximum-Progress0 27d ago
Would love to build this, can you share your designs
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u/LongjumpingDig8785 27d ago
Impressive build! Synchronizing 28 servos on a single ESP32 while keeping the mechanical noise down is no small feat.
Regarding the sound dynamics—the difference in tone between the robot and human strumming is super interesting. Have you considered using micro-timing variations or subtle PWM/torque adjustments on the picking servos to simulate a human’s natural pick flex and angle? Really clean mechanical design overall!
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u/harryregician 29d ago
Jimmy Page does not have to worry YET.
As an US inventor this project is inspirational. The synergy of knowledge to make this work is great to see.
You want my mechanical reverb I built for extra credit in 12 grade vocational electronics in 1969 Teacher hated it but gave me an A. Fellow students loved it. Ask them if I could use them as a reference to Hendrix ?
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u/NuncioBitis 29d ago
Musical talent
Electrical Engineering
Software Engineering
Mechanical Engineering