Sagar Mohite is a computational artist and an engineer based in New York City. His work has been an exploration in combining principles of design and computational sciences to generate visualizations.

Posts from the ITP Category

Walkthrough for fabricating a 2 input NAND gate using two BC547 NPN transistors.


1 470 Ohm resistor.
2 1k resistors. (Alternatively 3 1k resistors).
2 BC547 transistors.

Simple schematic wired up in Eagle CAD.

NAND gate using BC547 NPN transistors

Here Pins 1 and 2 of the I/O header pins are Inputs and Pin 3 is the Output. I have used the Sparkfun Eagle libraries for my various components. Pin 4 is GND and 5 is Vcc.

Board Assembly

NAND gate board layout

NAND gate board layout

Post ratsnest and grounding.

Post ratsnest and grounding.


Sagar's EOS_20140917_19_03_52_Pro

Final Assembled Circuit

Sagar's EOS_20140917_22_47_29_Pro

Sagar's EOS_20140917_22_48_08_Pro

Sagar's EOS_20140917_22_52_30_Pro

The Force

The curiosity of flight never leaves me spiritless.

Ethereal flight or flight without the use of propellers or jets grabs people’s attention mainly because of the fact that there is something that feels supernatural about it. This added curiosity from the people helps us in designing more immersive interactions using existing technology.

Yoda pulled the X-Wing out of the swamp using only what is otherwise called ‘The Force’. Evan Wu and I wanted to create an experience which could allow people to feel the Force. For obvious reasons the X-Wing scene from planet Dagobah made sense. A magnetic levitation setup that rests on an actuator goes beneath the table and the actuator is controlled by your hand as seen by the Kinect.

Made with Processing, Arduino, OpenNI and Kinect.

Much love to Tom Igoe for mentoring us.

[More photographs]

[Draft Proposal for Automata Finals]


The Tectonicus is an automaton that responds in real-time to earthquakes occurring all over the planet.


Personal curiosity to realize how many tectonic plate movements occur in a day and how the ground that we feels to be strong and sturdy is actually floating around on the Asthenosphere.


  • Keeping the look and feel of the outcome autonomous and classic. In other words, even if at some point it is responding to a particular event, it should appear that it does so on its own accord and is not being told to do so by a microcontroller or any other device.
  • Keeping it small.


  • To be obtained as ATOM or GeoJSON feeds which are updated every 5 minutes from the United States Geological Survey (USGS) earthquake web service.

Possible iterations-

  1. Person shaking and falling depending on the magnitude of the quake.
  2. A world map on which a person with a hammer hangs. He jumps and hits the hammer to the location where the Earthquake occurs (location specific).
  3. A globe producing certain kind of an anthropomorphic response in any Earthquake occurrence event (neither location nor magnitude specific).
  4. A liquid container with the world map as it bottom. The liquid ripples near the epicenters. (location and magnitude specific
  5. A set of hammers hitting a hard clay block (again magnitude specific).

The wheel was made with the intention of reducing the effort needed to move things around. A few millennia later came the concept of the mechanical advantage and then simple and basic compound machines like levers, fulcrums, pulleys and planes drastically altered the definition of work for a human being. Speaking purely in physical terms, we started relinquishing some of the more physical and hectic jobs that required a larger amount of time, force and energy; and let machines take them over. Then there were machines and tools that were made to make other machines and tools to further reduce the physical involvement of humans in intense labor work. Over the decades, there was a slow drift in the genre of work/occupations in which majority of people involved themselves. Enter electricity the process of operating the machines was also automated. All that was needed now was the push of a button. This drift changed the way of work in two manners – firstly, it almost reduced the need of physical labor to a bare minimum (which was rather sudden and socially unsettling in the burgeoning modern age) and secondly, it opened up and broadened the potential of the kind and the magnitude of work that humans could accomplish. The drift in the genre of work gave us more time to think, create and experiment at the push of a button and so the 20th century witnessed many revolutionary developments in the methods of automation.

With the invention of the computer, logic became the neo-labor work. Things that needed redundant effort and time were now done by the computer. Basic calculations, conversions, analogies and pretty much everything logical could be done by a computer. The beginning of the 21st century was a time when pretty much every activity was moderated by computing machines in some manners or other. Transportation, manufacturing, fabrication, arts, sciences, health and medicine, defense, politics, design, communication and even spying were some of the things that computers were used for. Consequentially, the next big drift in the kind of work in which humans involved themselves arrived and it also changed the way of work in two manners – firstly, it almost reduced the need of doing the functional to a bare minimum and secondly, it opened up and broadened the potential of the kind and the magnitude of work that humans could accomplish.

I believe that thinking something that is not creative has always been met with an implicit and unacknowledged resistance which has been the very reason for inventing the new to do the redundant. Often, the new ends up being the redundant because of a simple thing called boredom. It wouldn’t be a bad idea to consider Pascal’s thought here – “we seek rest in a struggle against some obstacles. And when we have overcome these, rest proves unbearable because of the boredom it produces”.

This, I think, has been one of the major reasons for several minimalists and modern day thinkers to highlight the importance of keeping simplicity in mind while making products and services for people. We need the things that we need without having to do ten other steps[1] and so we bring in automation to handle the rest of the ten steps. Since our requirements have been constantly changing, that automated machine needs to be intelligent enough to have the outputs delivered to us without BSOD-ing. Crawford in his essay[2] says that for things to be labelled with the overused term ‘interactive’ it is necessary that we define a minimum ‘intellectual dignity’ that those things should have. So if its a machine that is interactive, it needs to have a qualifiable level of thinking and understanding. Defining this intellectual dignity in a logically programmable form is a challenge because the definition will essentially be human and hence nebulous. This is because logic almost always fails when it sees something nebulous and computers rely on basic logic loops. That being said, there are several reasons that lead me to think that this machine, if ever built, should be something that will bring about the next drift in the kind of things we do; and it would be a major drift because then we won’t be the exclusive set of entities in the world endowed with the power to think and labor would then be something ambiguous [3][4].

References –

[1] Don’t Make Me Think. S. Krug. 2000.

[2] The Art of Interactive Design. C. Crawford. 2002.

[3] For a Breath I Tarry. R. Zelazny. 1966.

[4] The Machine Stops. E.M. Forster. 1909.

+ high-res version

Making a Timid Box

The idea of a timid box originally nested from the notion of a living hockey puck which gets hit hard frequently and so is afraid of humans in general. The following is a 3D render of the first concept. It roams around slowly and conspicuously in areas of the room and immediately hides its top shelf having its eyes if it detects danger.


[This post is for personal documentation purposes only and may not be self explanatory]

This is an alternative method for a achieving a three dimensional actuation using only two motors. I am using a solenoid for switching between two different planes of motion (say x-y and y-z).

Required –

  • 2 Bipolar Stepper Motors 12V/350mA (I prefer a minimum torque of 0.2 Nm)
  • 2 lead screws with shaft couplers.
  • 2 pairs of rails with grips and brushes.
  • 1 solenoid for interlocking and switching planes of motion.

Disadvantages –
The motion is not a continuous 3D motion and the speed is much slower as compared to an xyz-gantry using 3 motors. In this setup, it is impossible to travel from point (x1, y1, z1) to (x2, y2, z2). Instead it travels as follows –  (x1, y1, z1) -> (x2, y2, z1) -> (x2, y2, z2).

2D 3D actuation

J.R.R.T’s lines echoed in my brain as I stared at the circuit (also it feels kind of cool to LOTRize everything). I was literally using the exact same configuration for the last three things that I built.

On a more serious note, this was just a fun post on the usual boilerplate IPO circuit because I realized that it makes up most of the things that have been making life simpler and easier for us (well atleast me).

the one ring vs arduino image

So another week passed and I finally decided to deal with the procrastination that was holding back my blogging activities. Whenever I sat to blog down my work I used to find something relatively more exciting to do. But I kind of figured that a log must be maintained, for one day (and that day may never come) I might run out of exciting stuff to do and I might have to turn back to pick a leaf from my past.

We made a mouse today! Even though it was a perfect little mouse, it simply could not resist eating the cheese we offered. But I can distinctly remember the feeling of satisfaction when we controlled the speed of the mouse’s motion. Well it wasn’t technically alive, so there was no guilt of altering its free will and sorts; but there was a limitation. Although we could control it’s speed and motion to a certain extent, we never managed to train it to not eat the cheese lying infront of it.

“He said it could be done using two sensors!”, I said to my partner, who was also trying to figure out how to get it running up and down and not just left and right. Then we decided to consult him again and as always help was provided for those who sought it! We fixed our programs and got the mouse running up and down as well.

However, the additional degree of freedom also convoluted the problem that we were having initially. The mouse would almost every time eat the cheese we offered. It was very difficult to control it.

This was when I decided to put it to test. I tried to evaluate the mouse (qualitatively) on Don Norman’s three way structure.

The Visceral Mouse
We had already dismantled it so there was no question of putting it together to be evaluated by others. So I tried to clear my mind after which I asked myself whether it looked or felt good?. Of course I could not get a clear perspective as my reflective was veiling my vision and telling me its bad; but some part of me kind of liked the way it looked. Maybe because it was an exposed piece of hardware and looked crude. I personally like such purist imageries. At the same time I could imagine people not liking it because it did look ugly after all. It did not feel good at all though – flimsy, weak and prone to damage every time someone touched it. So on the visceral level our mouse fared poorly.

The Behavioral Mouse
Well it was working, but it ate the cheese every time we tried to steer it.
One could use it, but it was definitely not usable.
Enough to say that it failed on the behavioral level.

The Reflective Mouse
I started with a presumption that it would fail the reflective level too. As I began assessing, it turned out to be an altogether different story. Well it was definitely not good at not eating the cheese, but it was amazing at doing weird things after we moved our hands over it. So maybe it was not meant to be a utilitarian mouse in the first place. Maybe the thing we made needed to have a redefined purpose and not just be a mouse that someone can control. (Because if controlling is all that is required then the need of the hour would be Darth Vader). It occurred to me that redefining the purpose could completely change the way the visceral and the behavioral tests were made in the first place.

The mouse definitely passed my reflective test. Because even though I thought that it was unusable and lacked smartness, it opened up a pool of infinite possibilities on how a small tweak could make it a something very different from what it is. On one hand, you add thousands of photo-resistors to it and it becomes a panel that can detect finger gestures and on the other hand you remove one photo-resistor from it (and also add a piezo) to have your own mini Light Theremin that sounds like R2D2!

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