Configurable Motor Matrix

Configurable Motor Matrix
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Hi STEM enthusiasts

The post was long due. Here is some interesting update. Finally, after some iterations, we come up with the prototype version of the configurable motor matrix which can be used as a model system for cognitive science experiments. This is also special because this is one such project where makerspace and LSR team collaborated. If anyone of you is interested in knowing more, you have to visit the lab and experience it :slight_smile:

Here is how the Prototype Version 1 looks like:

What’s happening here? Here you can see @jtd aka Jude who designed the prototype trying to sense the different vibration pattern which can be generated by these tiny circular vibration motors on the skin. We generated a linear, snake-like pattern that was clearly distinguishable when kept on the skin.

How does it work? Its simple, you coordinate the switching (ON/OFF) of the motors in sequence using a micro-controller( here we used Arduino Uno). Currently, there are 16 vibration motors attached to a flexible matrix which we designed and 3D printed.

Here is how the 3D printed design looks like? We used openscad to design it.

Here is a brief pictorial journey along with some goof-ups!

13 Dec 2019
We started with the design of a vertical mount for motors and printing it using a flexible filament. We designed a 2*2 matrix for exploration purpose and played around with the duration for which the motor was kept ON and then OFF duration.





Here you can see Jude and GN testing the design.

Later, we also tried a linear strip where one can change the distance between the motors too.

19 Jan 2020- v1.0
This can be called the prototype version 1.0. Here we printed the 7*7 matrix and it was working fine but the problem was the fragile connection near the motor ends which can break easily if one applies force on the wire.


We all were excited about the trying it out!

Top View - I know it looks bit wire-y, but we do plan to design a PCB to reduce that too.

GoofUp = More Learning!

What’s inside a single motor? This is what happens when the connection gets broken. There is an epoxy coating on the flexible PCB near the ends which makes it extremely hard to re-solder. One of them came out, so we used this opportunity to open up the motor to explore what’s inside! Can you guess how does this vibration motor works?


28 Jan 2020 Version 1.1 with the requisite modifications


Do you see the small pieces on the table, that fit on the top of the vertical column and presses the wire so that the tension near the joints is minimized during usage.

Resources:

The Arduino code and design files can be found here

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The motor has 2 tiny wires 10mm long and 1mm dia soldered and epoxied in place. They are extremely fragile. We designed a small stopper to prevent the wires from breaking.

While use case requires repostioning motors to do aTwo Point Distinguishing Test, pulling out the motors and reinserting them is a tedious and fault prone task due to the wires.

The stopper will be redesigned to also act as the motor holder. The motor + holder will become a single unit and Insertion / removal from the matrix will be as one block.

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configurable motor matrix what does this mean
i’m just a learner and want to know about this

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Sure. So basically we can have different pattern of vibration by following two methods or combination of these

  1. You can change the physical location of the motors and get different vibration pattern
  2. Once you lock a specific physical location pattern, you can also now program individual motors and generate several different vibration pattern.

So, essentially, you have lot of flexibility to play around with many different combinations.

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Sir what are the applications of this configurable motor matrix as I am just a learner and have no idea about this

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I don’t know what the designers have in mind, but one almost obvious application is the ability to convey haptic messages using either a sequence or shape of tactile impressions, or both simultaneously.

A sequence creates or lends itself easily to a linear script, whereas a shape (and a shape with sequence) lend themselves to multidimensional scripts.

A ‘sheet’ of actuators binded to the skin can thus be a digital display for tactile scripts. These are useful for those who have no choice but to use tactile displays in place of visual or aural displays, and also to communicate with those who the situation places in silent circumstances, such as firefighters and investigators of chemical accidents.

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Apart from the above haptic use by differently abeled folks, the application here is to provide a sensory experience of abstract parameters eg vector computation, which should improve learning of such abstract stuff.

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I did mention differently abled, but (while the imperative to create script alternatives for those who have early learning impairments for whatever reason is certainly critical) I think it is important for all humans to have some experience of communication methods that are out of the mainstream. We take touch for granted, but very few of us are capable of using touch as a tool for grainy communication.

Even those we think of as unimpaired might actually need assistive technology tools in ordinary day to day circumstances, as is likely to happen to a majority of people entering the group of those negatively impacted by age.