Toilet Paper Indicator: Mechatronics Final Project

During the Spring of 2021, I took the Mechatronics Course (MAE 3780) at Cornell with Professor Hadas Kress-Gazit. I chose to do the final Open Design Project in the field of Home Automation.

Though I'm not proud of it, I have been the victim of sitting on the toilet and forgetting to check if there is toilet paper remaining many times. As the final project for Mechatronics was Open Design, I chose to design a visual indicator to alert a bathroom user if the toilet they are about to use does not have toilet paper.

The device uses an ultrasonic sensor, servo, LED lights, and Arduino to accurately determine when the toilet paper roll is empty or very low and that the next user should replace it before sitting down. The ultrasonic sensor is positioned carefully to not capture the toilet paper roll when empty and thus, return a value much higher than before. The arduino performs a time average in order to account for fluctuations in the motion of the toilet paper roll, especially when its being used. The servo has two LEDs mounted on it, a red and green, which conform to standard expectations for the meaning of those two colors. Most of the structures are mounted or created using cardboard because of the tight budget we were given and the abundance of cardboard in my house at the time.