Hello!

I am using Pololu accelerometer MMA7361l and it is very good product.

I allready measure, tilt from 0° to 180° with using x and y axis and it is very precise. Now I want to measure acceleration in SI unit - [m/s^2]. But I don´t have any idea how to do that in program. I use Bascom.

I hope you understand the question and you can help me

Bye

*sorry for my bad english.

If the accelerometer board is stationery, then it will be measuring the acceleration due to gravity which is 9.8 m/s^2 in SI units. This will be divided vectorially among the three axes according to the orientation of the board.

If you have calibrated the accelerometer so that each axis has the same gain and zero offset, but in arbitrary units, then simply calculate the final scale factor S = 9.8 / sqrt(Ax^2 + Ay^2 + Az^2).

The acceleration in SI units along each axis is then given by S*Ax, etc.

Keep in mind that without other sensors, like a gyro or a magnetic compass, you cannot easily separate acceleration due to gravity from acceleration due to motors or other forces.

The accelerometer returns a voltage which represents the acceleration it is experiencing on each axis. The conversion constant is dependent on the sensitivity and can be found in the accelerometer’s datasheet (in units of g), which is located under the Resources tab Resources tab of the product page:

A g is 9.8 meters per second squared.

Unfortunately, I am unfamiliar with Bascom and cannot help you with writing the program.

- Grant