Most of us spend hours infront of laptops sitting on ordinary chairs and we don't care how we are sitting, Are we sitting in a good way? I think the answer is no, because after all theses hours of working while we are sitting, we feel the pain,Backache, Neck-ache and etc.
What if we transformed our ordinary chair to a chair that gives us alerts when we are sitting in a wrong way?
Let's jump to the steps to see how we will do this.

Step 1: Components Needed

Hardware :
1- Arduino Uno, you can buy it from here
2- 1sheeld board , you can buy it from here ,to know how to use 1sheeld check Getting started with 1sheeld and read about Data logger shield and Buzzer shield as we are going to use them in our project
3- Male/Male Jumpers
4- 2 piezoelectric sensors, you can buy it from here

5- 4 meters wire ( used to make the terminals of the piezoelectric sensor longer) ( I used wires of a damaged mobile charger)
6- Tape
7- Breadboard
8- 2 LEDS
9- 4 resistors ( 2 of them > 1MegaOhm , 2 of them > 100 kiloOhm)
10-USB Cable
11- Android Smartphone

Software :
1- Arduino IDE , you can download it from here
2- 1Sheeld Mobile application , you can download it from GOOGLE PLAY STORE

Step 2: Connecting All Things Together

- White LED is for detecting that the upper piezoelectric sensor ( which will be mounted on chair's seat) is sending data to Arduino
- Yellow LED is for detecting that the lower piezoelectric sensor ( which will be mounted on chair's back) is sending data to Arduino
- the upper piezoelectric sensor detects that you sat on the chair,While the lower one detects that you are leaning your back on the chair ( having healthy sitting )

Step 3: Arduino Code

- What the project actually does, it detects if you are leaning your back or not, if you are not leaning your back Buzzer shield on your Mobile goes ON, When you lean back the Buzzer goes OFF and data logger shield saves how many unhealthy sittings you had and at which time in a CSV file.
- As you can see in the pictures, this is the same CSV but I took three screenshots for it just to show you the time saved, you can notice that they differ in seconds as I sat 6 successive unhealthy sittings.
- Illustrated Arduino code in the attached file.