So here we will be discussing the main components used and then working of the whole project and more stuff in detail.
The main component of this project is microcontroller ATTINY85 and MPU6050 - the Gyro/accelerometer sensor. Then we have other components like vibration motor/sensor, battery and switches.
1> ATTINY85 microcontroller
The main reason for using it is because it is one of the smallest uc, having 8K FLASH which is sufficient for programming, 512B RAM and it supports SPI interfacing which is required to wirk with the MPU6050 Accelerometer/gyro sensor. It has 6 no. of I/O's which is enough for interfacing with other components.
ATTINY can be operated with 2.7V to 5.5V so easy to use with 3.7V rechargable batteries.
2> MPU6050 Accelerometer and Gyroscope Module
The MPU6050 is a Micro Electro-Mechanical Systems (MEMS) which consists of a 3-axis Accelerometer and 3-axis Gyroscope inside it. This helps us to measure acceleration, velocity, orientation, displacement and many other motion related parameter of a system or object. This module also has a (DMP) Digital Motion Processor inside it which is powerful enough to perform complex calculation and thus free up the work for Microcontroller. It also supports I2C Communication protocol.
It`s working voltage range is 3V to 5V.
3> Viberation Motor
It`s used for feedback/alert purpose. It has operating voltage of 3.0V
4> Battery 3.7V
Lipo Rechargeable Battery
Lithium Battery Charger Module having Input interface as Micro USB
First while programming the microcontroller we define the cutoff for the Accelerometer /Gyroscope sensor. By cutoff I mean the value where it triggers and activates the vibration motor/sensor.
So Accelerometer/Gyroscope tracks the cutoff value ---> if value crossed ----> sends signal to microcontroller ----> microcontroller activates(or deactivates) the vibration motor/sensor(or LED in case for prototype circuit, which is used for optical fedback for human eyes, the LED may be removed in final make of the device.)
Thus it alerts the user for correcting his/her posture.