Rock-A-Bye Baby, On The Mechatronic Crib Shaker

While an engineering mindset is a valuable tool most of the time, there are some situations where it just seems to be a bad fit. Solving problems within the family unit would seem to be one such area, but then again, this self-rocking mechatronic crib seems to be just the cure for sleepytime woes.

From the look of [Peter]’s creation, this has less of a rocking motion and more of a gentle back-and-forth swaying. Its purpose is plainly evident to anyone who has ever had to rock a child to sleep: putting a little gentle motion into the mix can help settle down a restless infant pretty quickly. Keeping the right rhythm can be a problem, though, as can endurance when a particularly truculent toddler is fighting the urge to sleep. [Peter]’s solution is a frame of aluminum extrusion with some nice linear bearings oriented across the short axis of the crib, which sits atop the whole thing.

A recirculating ball lead screw — nothing but the best for [Junior] — and a stepper drive the crib back and forth. [Peter] took care to mechanically isolate the drivetrain from the bed, and with the selection of the drive electronics and power supply, to make sure that noise would be minimal. Although thinking about it, we’ve been lulled to sleep by the whining steppers of our 3D printer more than once. Or perhaps it was the fumes.

Hats off to [Peter] for a setup that’s sure to win back a little of the new parent’s most precious and elusive commodity: sleep.

13 thoughts on “Rock-A-Bye Baby, On The Mechatronic Crib Shaker

  1. So much fuzz where the solution is so easy. We bought a large spring (you can even buy dedicated ones for not much money) and hung our kids in their “bag” (I don’t know the English word – I’m not a native speaker) of their “Kinderwagen” (stroller?) to it (good hook in the ceiling needed, too) and fixed it with some additional ropes that it stayed more or less balanced and could not turn over to any direction.
    The baby moves – the bag starts to swing and gets slowly damped. Worked out perfectly. No motors necessary. Really self-rocking.

  2. This just SCREAMS for a video. It leaves so many questions: What does it sound like, what kind of speeds can it do? What feels like a nice resonant frequency of the bed, what motion profiles can be used? (sinus, ease-in/out, PID, sawtooth, leineair)? Can you upgrade it with a noise detector to start rocking when the bay cries? Or , oh, wait! even better a PID with the baby’s crying dB as input! Oh man, this really needs a follow-up.

    1. I just get a hilarious mental image of a control loop going horribly wrong. Small child in an industrial bowl counter situation perhaps.
      Large springy bit of metal, as per the old Victorian style child catapults, suddenly look pretty good from a kiss perspective.

  3. I built a cradle rocker from a 24V DC motor / geartrain assembly salvaged from a laser printer, running on 12V from a plugpack. The crank arm was adjustable and the drive assembly screwed to bits of wood and attached with long bolts with wingnuts. I built it in a day. One thing was that it did not operate smoothly as the mechanism acted as a powered brake at the outward ends of the sinusoid cycle, rather than letting it descend smoothly. A counterweight above the pivot point would have helped but I didn’t want to put any part of the mechanism above the pivot points. Somewhere I have a bit of video of it operating.

  4. I know this is not “buy the commercial product-a-day”, however it seems worth mentioning that there is a commercial product that is (sort of) similar to this called the snoo. It’s very expensive, but mostly very well regarded/reviewed. This DIY repair video is the best view at the inner workings that I’ve seen so far:

    Nice to see some other DIY ways of achieving similar effects.

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