[Ancient] has a video showing off a fascinating piece of work: a lip-syncing robot whose animated electro-mechanical mouth works like an IBM Selectric typewriter. The mouth rapidly flips between different phonetic positions, creating the appearance of moving lips and mouth. This rapid and high-precision movement is the product of a carefully-planned and executed build. When we featured this project before, we wanted to see under the hood. Now we can.
[Ancient] dubs the concept Selectramatronics, because its action is reminiscent of the IBM Selectric typewriter. Instead of each key having a letter on a long arm that would swing up and stamp an ink ribbon, the Selectric used a roughly spherical unit – called a typeball – with letters sticking out of it like a spiky ball.
Hitting the ‘A’ key would rapidly turn the typeball so that the ‘A’ faced forward, then satisfyingly smack it into the ink ribbon at great speed. Here’s a look at how that system worked, by way of designing DIY typeballs from scratch. In this robot, the same concept is used to rapidly flip a ball bristling with lip positions.
We first saw this unusual and fascinating design when its creator showed videos of the end result on social media, pronouncing it complete. We’re delighted to see that there’s now an in-depth look at the internals in the form of a new video (the first link in this post, also embedded below just under the page break.)
The new video is wonderfully wordless, preferring to show rather than tell. It goes all the way from introducing the basic concept to showing off the final product, lip-syncing to audio from an embedded Raspberry Pi.
Thanks to [Luis Sousa] for the tip!
Cool was waiting to see a if they used a stepper or a whiffletree.
Thanks. I still hate it.
yeah, nope
The video is worth watching just to see how he swaps out the shaft of a stepper.
I didn’t know you could do that!
It does usually end up reducing the maximum torque when you take the rotor out. But for some applications that doesn’t matter.
I’ve heard that, but why, exactly?
Ditto.
Is it the inability to achieve some alignment perfectly upon reassembly?
I think that warning goes back to the original stepper that used pre-neodymum magnets. Strong alinco magnets must have a steel keeper across the poles for a complete magnetic circuit at all times to prevent loss of strength. I don’t think modern steppers with neodymium magnets have this problem. Somebody should test.
The stator behaves as a magnetic “keeper” for the magnetized rotor, by closing the magnetic circuiit. When you remove the rotor, the magnetic field lines are forced to go through the air (with its puny magnetic permeability) and this can weaken magnets of low coercivity. At least that’s what I remember.
Magnet keepers were common on old horseshoe magnets when storing them.
The real question is how they put the rotor in there in its highly-magnetized state to begin with.
This reminds me of President Lincoln’s ‘Picture Phone’ in the Amazing Screw-On Head (https://youtube.com/clip/Ugkx6EsSgqt8mSWEVCb–ur9A_Ci_ClyAu8T?si=SJvnCG_ZfBufZiwN).
This whole project reminds me of Al Jolson for some reason
Every step of that construction was a delight, and I learned a great deal by watching that video.
Shame the effect doesn’t work. I was only occasionally able to relate the sounds I was hearing to the lip-flaps I was seeing.
Maybe the problem is with the camera, and in “live” it works better.
I think it might work better if you paint the lips or add some other contrast to the mouth
My first fix would be to strobe the lights in time to the movements. Works wonders for film projectors.
Interesting idea. The maker should try that.
But I agree some more contrast to the mouth would also help.
What I find odd too is that with all that effort a choice was made to make the eyes flat, why not rounded? You can also easily move them that way, in fact it’s easier since you can pivot instead of shifting. Not that the eyes are moving at this point it seems, but a slight rounding would look better I think, doesn’t have to be a full globe-style rounding mind you.
And talking of color, maybe if the mouth ball was different color it would work, maybe the closeness of the color to that of the face makes you more aware of the edge. Although there is a risk you’d get accused of ‘blackface’ if you made it a different color carelessly :)
You could try colors with a video editor I suppose, you can just select the region of the mouth and apply a color filter.
It almost, almost works for me, from time to time. It’s missing some lip-flaps so there’s overlap, and doesn’t work at all when the speech speeds up, but when it’s slow and well enounciated, it’s almost there.
This is some fantastic hobby engineering.
I think the effect would be materially improved with some better contrast–paint the teeth white, the open mouth cavity flat black, with tongue and lips some shade of red.
As is, the shapes are lost in monochrome, and shadows are insufficient to reveal changes in mouth geometry… especially with the blur of the ball’s motion.
This would be a great prop for a steampunk movie…
Why did I have to be born with a dirty mind…
Now you made me wonder if there is a fetish where people suck shins..
Oh well, sounds innocent enough :)
Rule 34
Maybe I miss something – how do yo move the steppers so quickly?
Minimal mass, a motor with plenty of torque, and a stepper driver that handle high speed smoothly.
Bro saw the uncanny valley and yelled “geronimo.”
I’m not really feelin’ the animation vibe. But, if it could be made to compactly, alternately expose ten segments, I think it might make for an interesting analog score display element. Like what might have happened if electromechanical arcade games had continued on without being supplanted by digital electronics (or maybe just provide inspiration for the lamest episode of “Sliders” ever).