Mathematics has always been a riveting subject both conceptually and practically, for the longest time. On my way to practising design, I discovered an outlet into art based off of mathematics. We are going to make a ‘Harmonograph’ based on physical computing using an Arduino.

A “harmonograph” is a drawing machine that makes geometric patterns that are related to the frequencies of activity on (at least) two actuators. These can be made using rotating platters where the relative speed and direction of the multiple rotating platters controls the figure being drawn. Even a simple harmonograph as described can create ellipses, spirals, figure eights and other Lissajous figures.





Proposal: Draw your mood

Imagine we have a twitter mood light, connected to a mechanical arm which draws. I want to make this amalgamation of Arduino projects which detects and ‘senses’ the world mood and represents it via a drawing. After much deliberation and research, I feel that the twitter algorithm has changed(even though I have found a few, wherein this is possible) and it is not possible to tap into its data.

Another possible iteration is to make a device which captures emotions using the press of a button and at the end of the day draws an image based on the prominent emotion of that day. Example: There are a few buttons installed at the PoD, people press(Happiness, Anger,Fear and more), at the end of the day the device captures the most dominant ‘mood’ and draws( I think I have to manually put in the image I want it to draw, though.) a painting relating to the most dominant emotion.

This can also be captured using the Vortolight method which uses a service like IFTTT to reflect colours based on what people tweet about. Essentially instead of changing colour, I would like to ‘move’ the drawing handle in a way which relates to a tweet.

Example: I am angry today #red. This makes the vortolight go red, in the same manner, the robot will draw a little something over a prompt by the tweet.

I looked at a few drawing robots and this seemed the most viable/accurate in terms of using a MECHANIX kit and servos(besides regular electronics) whereas the twitter part is mostly coding and web services(and a wifi module which should not be as expensive, however, the one used in some cases is).


Looking forward to starting with this after your feedback!


This simple toy is my subject to teardown. Powered by AAA batteries it involves a rotatory motion and lit LEDs when a button is pushed.

The initial unscrewing yields the inside of the toy.


Taking out the useful part from the casing shows a button, 5 LEDs,small circuitry,a motor and connecting wires.


Exploring each section separately, the lighting component of the toy is shown. Consisting of 5 LEDs connected in a simple circuit.The only use of the circuit board is powering the LEDs,which are soldered to the board with wires.


The Pushbutton type switch is used to operate the toy.These switches complete the flow of electricity when they are pressed. When a pushbutton switch is in the on position, a spring inside the electrical device makes contact with wires that will allow the current to flow. Then, when the switch is pushed down again, the spring inside retracts, and this stops electrical current, deactivating the device.


For the rotary motion, the toy uses a brushed DC motor.


The final layout is shown as,


The tools used in this operation are,



Part-Manufacturing Technique

Head- Making a mould and casting

Body- Making a mould and casting

LED Lights- A semiconductor wafer,multiple wafers are joined to become a semiconductor,Ultrasonic process to clean it.

Electrical components- Include highly detailed intricate processes,although very cheap to make.

The one design choice I like is the simplicity of the button placement. Very child friendly and surprisingly sturdy.