Introduction: An Optimistic Poetry Generator: Using Thermochromic Pigment and Nichrome Heating Pads

Poetry, polity and power is an optimistic poetry generator- a system that can be fed text that embodies human prejudices- hate speeches, biased policies, misogynistic statements- and it removes certain words to reveal poetry that is hopeful and optimistic.

It is the culmination of two disparate ideas that I have been intrigued by for quite some time now. The first is about a new kind of interaction that is emerging between human beings and machines as technology gets integrated into everyday processes. The common perception of technology or computerized systems being objective is a myth- they embody the values and perspectives of the people who design them. The second is about the power of art and poetry- and how they can be used as dynamic tools for resistance. I wanted to create a system that would automatically generate poetry from the source text- without human intervention. I see this project as a conceptual prototype that captures the essence, the value inherent in that idea.

Meant for individuals with intermediate understanding of electronics- and some prior experience of working with the Arduino micro controller specifically.

There are mainly three components of this project- the external build (ie. a box), the text cards along with the heating pads, and finally the actual circuit itself. So, let's dive right in! Happy making.

Step 1: Crafting the Box

Things you will need

1. 1/8" thick chipboard (Optional)

2. Access to a laser cutting facility (Optional)

3. Multi-purpose glue

4. Heaps of patience

We begin by making the box that would house the system. I chose to laser cut it from 1/8" chipboard sourced locally, using an online template. The dimensions I chose were length = 6", width = 4 1/2", and height = 6". This step is customizable- you can choose the size and material according to the requirements of your project. Also, note that you do not need access to laser cutting facilities to follow along- you can make your own box using common stationery supplies.


The top face has a rectangle cut out- where the heating pads will go later. There is also a circular opening for a photocell*. You can assemble the rest of the box, but remember to leave any one side open so that the circuit can be inserted with ease.

*You could use any input sensor in your circuit- I chose the photocell because I wanted my circuit to be activated only when the piece of text was placed on the poetry generator- to avoid overheating the Nichrome wire pads. The photocell (detects a change in the amount of light) is a small, lightweight and reliable alternative to the proximity sensor (detects the distance of objects from it) which gives faulty readings more often.


I also laser cut some alphabets, because I wanted to include the name of the project on one of the faces.

Step 2: Let's Make the Text Cards!

Things you will need

1. Black thermochromic pigment (You can find some here)

2. White acrylic paint

3. Paintbrushes

4. Paper (I used 160 GSM/ 98 Lb paper)

5. Laser cut paper screens (Optional)

6. Masking tape (Optional)

Step 3: Text Cards Contd.

With laser cut screens

Mix the thermochromic pigment with white acrylic paint. Use masking tape to stabilize the screen. Apply the pigment + paint mixture on the screen, with the help of a paintbrush, and transfer the text onto paper.

This step requires a lot of experimentation. Play with the ratio of thermochromic pigment to acrylic paint. Make batches with mixtures of different consistencies, try printing on different kinds of paper!

Without laser cut screens

You can paint the words directly on the paper using a brush or a tool of your choice.

Step 4: Making the Heating Pads

Things you will need

1. Cardstock

2. Access to a laser cutting facility (Optional)

3. Nichrome wire

The next step is to make the heating pads- Nichrome wire wrapped tightly around a paper core. Nichrome wire has a high resistance. When current passes through it, heat is generated- a property that we will utilize to change the color of the thermochromic pigment.

You can try exploring different designs for your heating pads. Remember to use a sufficient length* of the wire, and wrap it tightly. For instance, in the image above, the heating pad on top proved to be ineffective because the length of the wire used did not have sufficient resistance to produce the required amount of heat and thus change the color of the thermochromic pigment.

* I used 2ft of 3.26 AWG Nichrome wire to make 1 heating pad.

Step 5: Ok. Reminder.

This is important to remember- the heating pads need to correspond with the position of the text. While attaching the pads to the base remember to check whether they align with the position of the words.

Step 6: Controlling the Heating Pads Through the Arduino

To control one heating pad, here are the things you will need

1* Arduino Uno

1* Full sized breadboard

1* TIP120 transistor

1* 100 Ohm resistor

1* 100K Ohm resistor

1* 1N4007 diode

1* wall wart

1* barrel connector

Jumper wires

Alligator clips

Step 7: Wiring Your Circuit

There are two different circuits within the same setup. The first is the photocell, that is controlled by the Arduino, and powered through the USB jack of our laptops. The second is the high-load heating circuit, that is powered through an external source (i.e.. a wall wart) because the Arduino cannot supply enough current to it.

We use the photosensor as a switch. As soon as the value of the photocell reading crosses a threshold, a small amount of current is applied to the base pin of the transistor, that then completes the heating circuit.

The circuit diagram given above is for one heating element. Each heating element, depending on the number of words to be "cleared" will have to be connected similarly. For the setup I was using- I had 5 heating elements- I used a 5V 5A wall wart to power the circuit- which was sufficient. Depending on the number of heating elements you may have to change the power supply.

Also, it was helpful for me to number all the wires I was working with- although once you finalize the circuit, and get it to work you can solder the elements permanently.

Step 8: Uploading the Code

Upload the code. Run. Debug- you will need to adjust the threshold value for the photosensor depending on the lighting in your workspace.

Step 9: Integrating the Circuit With the Box

The last part involves attaching the heating pads and its base to the top face of the box, inserting the circuitry inside the box, and closing the box.

Step 10: Seeing It Work

It is interesting how basic materials and mechanisms can be used to express such profound concepts. Such are the joys of prototyping!