This assistive device is designed to help me maintain focus and speed when reading physical books. Engineered to clip onto any book like a portable reading lamp, it utilizes a red line laser that sweeps vertically down pages and acts as a guide for the eyes. Users can customize the sweep speed with the potentiometer based on content difficulty etc.

Process

Designing the CAD for laser cutting was challenging but building and refining cardboard prototypes to figure out the exact shape and dimensions made the process slightly easier. Soldering was also time-consuming, as mistakes often forced me to restart from scratch. To avoid errors, I settled on a system where I build a complete working model on a breadboard that I can replicate precisely. If the breadboard and protoboard sizes don’t match, I use a larger breadboard and tape off an area that mirrors the protoboard, then strictly stay within those boundaries. I now also know  that it is important not to move wires or components during the transfer; instead, I make sure to use duplicate parts from the inventory to recreate the setup cleanly on the protoboard. 

Discussion

I am technically satisfied with the coding and wiring but I am disappointed with the physical execution and the overall "flimsiness" and “aesthetic” of the final build. My original goal was to create a rugged, durable device that could be thrown into a backpack or used at the beach, yet the current iteration feels far from that vision. I think this gap between my vision and reality stemmed largely from my struggle with 3D visualization and my limited experience in CAD modeling. I also lacked the design sense to have a clear mental image of how the components should intersect. This resulted in me having to use glue gun glue and tape. I ideally would have designed interlocking panels and proper cable management with built-in hoops. 

If I were to continue developing this, I would start by exploring existing hardware like a gooseneck arm, possibly combined with the kind of book clamp already used for reading lights, and adapt my system to fit within that structure. I would also 3D print a more refined, circular housing for the servo motor and laser at the top of the arm to improve both stability and aesthetics.

During the in-class critique, a judge suggested implementing a calibration system where users can define the reading range by using a potentiometer to select the top and bottom lines. This aligns with a goal I had but wasn’t able to achieve in time. I would implement this right away. I also received peer feedback about the laser color, including “is it comfortable to read text highlighted in red?” and “Would you have different light color for the highlight?”. There were also suggestions like “would be nice to be able to pause the device, in case i want to go back and read.” and “Maybe in the future you could add a pause button if I get interrupted or something”. While these weren’t changes or features I felt I wanted, if I were to develop this into a consumer product, I would want to conduct more user research to better understand preference.

Technical information

/*

 Project 2: Reading Pacer

 60-223 Intro to Physical Computing

Uses a servo motor to drive a horizontal line laser vertically across a book to pace a reader. 

*Note: sweep distance is mapped to the size of a specific book: "Artists Re:thinking Games" by Ruth Catlow (Dimensions. 15.24 x 1.02 x 22.86 cm)

Code written for an Arduino Pro Micro. 

pin mapping:

Arduino Pin |   Role    |  Description

___________________________________________________________________

A0           Input       Potentiometer for speed control

10           Output      Drives servo motor

VCC          Power       5V to servo, potentiometer, and red laser

GND          Ground      common ground for servo, potentiometer, and red laser

Code released to the public domain by the author, 04/02/2026

Rion Kurihara, rkurihar@andrew.cmu.edu

*/

#include <Servo.h>

Servo verticalServo;

const int potPin = A0; // potentiometer 

// define sweep range of laser + servo

const int TOP_ANGLE = 60; // top of page

const int BOTTOM_ANGLE = 100; // bottom of page

void setup() {

  verticalServo.attach(10);

  verticalServo.write(TOP_ANGLE); // sets laser + servo position on startup

  delay(1000); 

}

void loop() {

  // 1. Sweep down by moving 1 angle at at a time

  for (int angle = TOP_ANGLE; angle <= BOTTOM_ANGLE; angle++) {

    verticalServo.write(angle);

    int potVal = analogRead(potPin);

    // translates potentiometer knob position into sweep speed = delay time

    int stepDelay = map(potVal, 0, 1023, 100, 3000);

    delay(stepDelay); 

  }

  // 2. Snap back to the top before next sweep

  verticalServo.write(TOP_ANGLE);

  // 3. Pause for page turn 

  delay(2000); 

}