# Accelerometer (gy-521) to measure velocity and Force

In my project i'm using Gy-521 accelerometer and Gyro to calculate velocity and Force. Just let me explain you few thing about the project. We need to make electronic football system i.e. When we hit the ball it should measure velocity and Force applied on it. To achieve this there is the Bluetooth link between the arduino and computer in order to connect with ball. Inside the ball gy-521 sensor is used to calculate velocity and Force. The problem is that... We got the raw values of three axis i.e x,y and z but don't how to implement this value to calculate the velocity and force. Please any help will be appreciated

F=MA... force = mass x acceleration

You hit the ball with one mass to transfer momentum to the ball with a collision model, how elastic is a football? Not as much as a billiard ball and nowhere near as simple!

Good luck. Your teacher(s) only expect so much so blow their minds if you can.

This will be a very difficult (if not impossible) task. The speed at which the ball rotates and the relative accelerations of the ball will mean that any approximations of the change in velocity (dv=a*dt) will grow increasingly inaccurate. If the ball was just translating, not rotating you might be able to get this kind of crude approximation to work, but when you include rotation then the approximations made by this approach become too significant.

When he wrote "electronic football" I thought the ball was virtual and the kick vector was gyro/accelerometer readings.

Instrument the ball has problems of its own. Where will the sensors, controller, etc, be?

There was a time when you would take a delayed exposure picture of the ball moving lit only by a strobe light with a grid in the background, but hey that worked great.

You can measure force directly. Force is what causes a mass to accelerate (F=M*a). Measure the mass of your ball (kg) and multiply your acceleration (m/s^2) to get Force (kg m/s^2).

You get velocity by integrating acceleration over time. Each time interval (s) multiply acceleration (a = m/s^2) by interval (s) to get the change in velocity: (m/s^2 / s = m/s). Add that to the the last known velocity to get the new velocity.

Note that you are going to be reading acceleration due to gravity in addition to accelerations due to forces. With an accelerometer alone there is no good way to know which way gravity is pulling. Perhaps a magnetometer can provide an orientation reference relative to the Earth's magnetic field and gravity can be subtracted that way.

I am getting REALLY bored merging cross-postings.

DO NOT CROSS-POST, IT WASTES TIME

@simpleman : Stop posting your question as a "report to moderator" or get banned.

Too late.
Banned.