Measure elevator speed

Question

hi, newbie to arduino buildouts. I was wondering if anyone could point me toward tutorials on something like the following:

i am looking to build a kit that would allow me to measure the starting acceleration, deceleration, and speed of an elevator (up and down). I have a pretty good idea of the hardware buildout but the parsing of the accelerometer data is where I think I am lost. I believe there are formulas for calculting (while taking into account gravity). Most of the tutorials stop at showing the stream of incoming data. I hope the grab the relevant bits, calculate and display the results.

i saw the simplelink Texas Instruments device...not sure if that is worth while or still just raw data.

Any my help would be appreciated.

thanks

chris

jdlui · Answer

Hi Chris,

I'm not exactly sure what you're seeking to do. Have you picked hardware? What type of interface are we talking?

If you buy a I2C interfacing IMU, you can very easily read out the acceleration data using the code libraries that come with the hardware. Adafruit for example has an IMU with great tutorials and libraries to get you started.

Adafruit IMU:

https://www.adafruit.com/product/1604

Setup guide and software tutorials for this IMU:

https://learn.adafruit.com/adafruit-10-dof-imu-breakout-lsm303-l3gd20-bmp180/software

Hope this helps!

Jordan

clem57 · Answer

Here is a demo of the bove https://learn.adafruit.com/ahrs-for-adafruits-9-dof-10-dof-breakout

jw0752 · Answer

Hi Chris,

If you are able to measure the acceleration and the time of acceleration accurately you will be able to calculate the velocity. Velocity = 1/2 Acceleration times Time Squared. The velocity itself will not be able to be measured using an accelerometer as once the elevator stops accelerating you will have no external reference point. 2 meters per second will feel exactly like 20 meters per second. If you are interested in speed of travel and where you are in the elevator shaft an accurate altimeter coupled to a time base will also work. Instead of measuring the change in distance with respect to time you will be measuring the change in air pressure with respect to time and the air pressure compared to the ground floor. Using the proper conversion formulas this data can be changed to meters per second and subsequently to distance traveled. Another challenge using acceleration is that it is not likely to be linear and you will have to integrate the change in acceleration over time to get an accurate velocity.

John