Final Project Journal

My final project us an automatic toilet paper dispenser. I was inspired by paper towel dispensers found in public and restaurants' toilets. Its an efficient way to use toilet paper, reduces waste and also reduces the spread of infection.

I had a rough idea about the design, so i decided to start sketching on Fusion 360 directly. First i designed the feed roller that holds the toilet paper roll. Then i designed the housing for the machine, which is a very basic design, yet very functional. Afterwards i designed the fork that snatched, cuts and rolls a piece of toilet paper. This fork will be attached to a 9V geared DC motor also via a special coupler that i designed.

Fusion 360 helped me design, assemble and check if my design had the potential to work when i fabricate it. I also used the Arduino IDE software to write the proper code for this machine.

The housing consists of 6 parts which are connected to each other via nuts and screws:

Feed roller rings in Fusion 360.

First, i fabricated the feed roller. I laser cut 50mm diameter circles and 30mm diameter circles in 3mm plywood and installed them on a 5mm stainless steel rod. This rod will be attached to the stepper motor via a coupler that i designed and 3d printed using PLA material.

I also designed and 3d printed the toilet paper fork that will be attacted to the geared 9V DC motor.

After laser cutting the housing and the feed roller rings, and 3D printing the coupler and the fork, i assembled the machine, adding all the components to their designated locations. The components include an Arduino uno board, a dc motor, a stepper motor, a push button and a roll bearing.

First, i wrote down the general concept of the device, which is extremely basic. When you push the push button, the stepper motor holding the toilet paper roll rotates the roll slowly that it dispenses a certain length of tape, which fall down between the forks arms. Then the geared 9V DC motor holding the fork rotates quickly that it "cuts" and rolls the specific length of toilet paper.

The components of this device are an Arduino uno board, a stepper motor with its drive and a dc motor with its drive too and a push button.

The dc motor, the stepper motor and the push button are all connected to the Arduino board. Using the proper code below, i can control the speed and timing of each motor after pushing the button.

The above illustration is the wiring diagram using the Fritzing software:

Its connected as follows:

*The stepper motor has 5 connections:

9V to 9V adapter.

GND to GND on arduino.

5V to 5Vpin on arduino.

D to pin 4 on arduino.

S to pin 3 on arduino.

*The push button has 2 connections:

Positive to pin 2 on arduino.

Negative to GND on arduino.

*The L298n dc motor driver has 8 connections:

VCC to 9V adapter

GND to GND on arduino.

5V to 5V on arduino.

IN3 to pin 8 on arduino.

IN4 to pin 7 on arduino.

ENA to pin 9 on arduino.

OUT3 and OUT4 to the DC motor.

Since both my stepper and dc motor need 9V DC, i chose a 9V adapter for this project.

The code is very basic. First i identified my inputs and components in the void setup. Then in the void loop i started an If condition when the push button is pushed, first the stepper motor will rotate in a certain direction with a certain speed for a certain amount of time them it stops and then the dc motors also rotates with a certain speed for a certain amount of time and that's it.

Then after making sure everything works, i assembled everything and tried it again and it worked perfectly.

Enjoy the final product!

Of course i asked my instructors for help and ideas. Amany and Ibrahim were kind enough to help through every obstacle i faced. One of the major ideas that's helped a lot was to change the locations of both the dc motor and stepper motor. My initial design had the dc motor dispensing the toilet paper and the stepper motor to snatch and cut it. But it was very difficult even impossible to control the amount of rotation of the dc motor and the stepper motor would pull the tape and not cut it because the dc motor doesn't have brakes like the stepper motor when its connected ti power. Then i changed their locations and the machine worked perfectly.

My biggest challenge was having to cancel my initial final project just 3 days before the deadline and start all over with an entirely new project. My initial project was also a dispenser but for adhesive tape rolls. It was a very interesting yet extremely challenging project, because it needs a lot of feed rollers and gears to work together in perfect harmony and the architectural aspect of the machine needed to be extremely accurate, more accuracy than the laser cutter and 3D printer can offer. So sadly i had to scratch this initial project and started on this project, which had to be a simple device to be able to finish it on time. I am still interested in fabricating my initial final project on my own time after the diploma, because i know its not impossible to make, i just need more time and more accurate means of fabrication.

My lesson from this experience is to learn when to quit on a failing project, and to initially choose a simpler idea:)