MIT Invents Alterable Pin Surface That Lets Objects Assemble Themselves | Hacker News Reader

MIT Invents Alterable Pin Surface That Lets Objects Assemble Themselves

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104 pointsmetakermit22 comments

It's a bit obvious, right? Or maybe I'm the only person that had a pin box toy as a kid (https://www.fatbraintoys.com/toy_companies/toysmith/classic_...).

Nine Inch Nails also did this: https://www.youtube.com/watch?v=mDsqpeiTqg8. Which, to me, is a bit more impressive even if it is CGI. A 3d pin video screen would be massively cool. I want to say someone else did a similar music video in the '80s, but can't remember.

Even academic videos aren't safe from folksy startup music.

Has there been a Kickstarter campaign to fund an album of folksy music for use in Kickstarter videos?

This is neat research. Probably not very practical or useful in it's current form, yet, you have to engage in highly speculative research and even consider the ridiculous to discover new ideas.

This version is unlikely to be able to compete in almost any metric with robot arms or even far simpler purpose-built machines (think simple 1 DOF automation used in manufacturing assembly lines, like bottling plants). With time interesting and unique applications of some future version of this might find a problem it can solve elegantly.

Yep, you never know, something like this could pay off for nano machinery, etc. You can't just benchmark against current top of the line robot arms. It is about exploring approaches, not selling to auto manufacturers within a year to replace what they are currently using.

The video has me thinking this is foreshadowing some new type of warehouse. Maybe Amazon is going to make a "life size" version of this.

Now if this is efficient in any way - no idea.

Here is a company that provides conveyor belt that is in the same vein as this MIT project https://www.festo.com/group/en/cms/10225.htm

Very impressive!

Not a word about of each "3d pixel" is implemented, which is a shame. I guess it doesn't have to be too complicated, but there sure are a lot of them even in this early prototype/lab version. They're also bi-directional, with each pixel having position-sensing.

This picture shows what's under the table: http://tmg-trackr.media.mit.edu/publishedmedia/Projects/2013...

oh, they look pneumatic. I'd guessed solenoid. In retrospect a solenoid is either just on or off. pneumatics allow holding any position.

A threaded-rod works, too.

True, although oftentimes way slower and getting the types of feedback they were using in the video would be tougher. On the upside, I'd expect this would work far better for heavier objects.

A regular threaded-rod would be slower, but you could speed it up by using a different thread profile with a longer pitch. If speed was the top goal, though, a belt-driven system could be as effective as pneumatics, but quieter. (But then you can't hold weight when the power is off.) Lots of trade-offs to consider, depending on design goals.

The prototypes I saw in person a few years ago were actually surplus automated potentiometers :) They were DC motors with gear reduction and a spool, with light steel wire coiled on the spool to slide the pot or the "3-d pixel" back and forth. these may very well be pneumatic.

I've been working on something similar for several years. (Alas, I don't have MIT's PR budget.) I call it "PinThing" and implement the pins as DC motor powered, 3D printable linear actuators. I use limit switches to detect end-of-travel, and a shaft encoder to measure distance traveled. Current goal is to make an array of four 3x5 pin blocks to make a digital clock display. One of these days I really need to finish and formally publish this project! One big challenge in the project is driving down the cost per pin to make a large array affordable -- that's why I focus on using 3D printable parts and cheap motors.

Here's a demo of one pin powered by Arduino and an H-bridge motor driver circuit: https://youtu.be/pLzDHLm01wM

Three.js software demo: http://pinthing.com

well you can buy a chinese knock-off of the actuators the MIT people used from spark fun: https://www.sparkfun.com/products/10976

I'm trying to drive the cost down to $1-2 per pin. It's obvious the MIT team did not optimize for cost. At $20/pin (from the SparkFun link), a 28-pin display (the minimum you'd need for a 4 digit, 7-segment display clock would cost $560. To so anything interesting, you'd want dozens or hundreds of pins. Cost is a huge reason keeping this idea from being more wide-spread.

Well if you really want to drive down the cost, the best thing to do would be to mass produce the actuators for the purpose. The actuators MIT used aren't really intended as actuators, they're some weird part for moving knobs around on high end audio equipment.

Now as it turns out, there really are linear actuators that cost about $1 per actuator, they're just tiny: http://www.alibaba.com/product-detail/Goteck-1-5g-Super-Micr...

From their paper: http://tmg-trackr.media.mit.edu/publishedmedia/Papers/527-in...

it appears they use 900 motorized slide potentiometers connected to bowden cables.

Current prices from mouser suggest that the actuators alone cost $23,000. This isn't a cheap toy, but it does show what we could do if actuators got cheap...

An early clunky version of programmable matter.

Could something like this be contained in a box, so that each of the sides has these on it?

That way instead of just working laterally, and from the bottom, things could be done from multiple angles. For example, solving a rubiks cube via machine typically involves at least three axes and servos, but with a machine like this that operated on three axes, I imagine a more power efficient method could be developed.

This is really cool technology, I love how simple it is in design, yet it evokes all kinds of ideas in the mind.

That is one perverse set of constraints.

Give me a few 1980s-vintage robot arms and I will outperform this system in any category except entertainment value. Robot arms once held great entertainment value and this system will become old media some day, too. Semiologically speaking, this system represents a silo of sublime resources from dopaminergics to labor and cash, but when the zombies come, I'll bet people will still run to the shed full of AK-47s.

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