Project Overview

Smart Toothbrush

Overview

The smart toothbrush is a custom microcontroller board that is built around an ESP32 processor. It contains an Inertial Measurement Unit (IMU) for tracking linear accelerations with an accelerometer and rotational velocities with a gyroscope. Additionally, a Real-Time Clock (RTC) unit is used for timekeeping. The data is written onto a MircoSD card. All these components are mounted on a Printed Circuit Board (PCB), providing a compact and efficient design. The electronics are protected from environmental influences by a customized outer case in the shape of a toothbrush. The result is a smart toothbrush with replaceable brushes that can be used for normal tooth brushing.

Below we show how we use the smart toothbrush at FAU's Machine Learning and Data Analytics Lab.

Key Features & Advantages

• The smart toothbrush does not differ significantly from a regular toothbrush in terms of handling and use.
• The outer case is waterproof and fully disinfectable.
• The measurements are taken automatically without any active intervention by the user.
• Low manufacturing costs thanks to standard components and low operating costs thanks to toothbrush with replaceable heads.
• Simple manufacturing and use of the toothbrush - no prior knowledge required, a documentation is available.
• Energy-efficient: Enables long battery operation.
• IMU data in research quality with a special focus on constant sampling rates without data loss.

Project Background & Concept

The advantage of measuring brushing behavior with the smart toothbrush is that you receive objectively measurable parameters. In addition, the person's normal toothbrushing behavior or routines are only slightly altered, and the smart toothbrush can therefore be seamlessly integrated into a person's life without any major effort or change to their daily routine. A data analysis can then be used to check e.g. the correlation of the data with the person's overall health.

Recorded Data Overview

The recorded data is written into text files which are permanently saved on the MicroSD card. Each text file contains the current timestamp in the format: dd.mm.yyyy - HH:MM,ss and the data of the Inertial Measurement Unit (IMU). The IMU contains a 3-axis digital accelerometer and 3-axis digital gyroscope. The accelerometer detects linear accelerations and the gyroscope detects rotational velocities. The accelerometer readings are X, Y and Z and the gyroscope readings are Gx, Gy and Gz.

Recorded Example Data

0. Reset_boot, 1. Boot:
Recording started at:
8.4.2024 - 20:25,32
Gx;Gy;Gz;X;Y;Z
0.02;-0.04;0.00;0.43;0.02;0.92
0.02;-0.04;0.00;0.44;0.02;0.92
0.02;-0.04;-0.00;0.43;0.03;0.92
0.02;-0.04;0.00;0.43;0.04;0.92
...

The recorded data can then be used to analyze the toothbrush behavior, as it allows insights into the intensity and regularity of movements.

Open Collaboration: How to Access Project Resources and Contribute

To make this project open and accessible to everyone, we publish all required information and materials here in this project. All required hardware and software files as well as the instructions for manufacturing and setting up the toothbrush are provided. The files can be found in the code section of this GitHub project, and the documentation can be found here in the Wiki section.
We are always happy to receive feedback and contributions. If you run into any issues or have any questions, please open an issue on GitHub.