current community

your communities

more stack exchange communities

Stack Exchange Inbox Reputation and Badges
tour help
Take the 2-minute tour ×
Arduino Stack Exchange is a question and answer site for developers of open-source hardware and software that is compatible with Arduino. It's 100% free, no registration required.
up vote 1 down vote favorite

I'm trying to get an arduino board to detect simple free fall condtions. Currently, I have a 9DOF sensor (https://learn.sparkfun.com/tutorials/lsm9ds0-hookup-guide) and am able to get the raw data from the sensor.

However I am unsure what to do from here onwards. From what I manage to gather, there is an alternative sensor ADXL345 accelerometer that has an inbuilt free fall component. I have tried modfying the code in such a way that it will work with the sensor I am using but to no avail.

The free fall detection does not need to be extremely accurate/precise considering there are many fall/jerk patterns. It is just for a proof of concept for a project of mine. With that in mind, any suggestions on how to proceed will be greatly appreciated (or if I should just get the ADXL345 accelerometer).

Thank you.

share|improve this question
1  
From the LSM9DS0 datasheet; "The LSM9DS0 may also be configured to generate an inertial wake-up and free-fall interrupt signal according to a programmed acceleration event along the enabled axes.". So it should be possible, just like with the ADXL345. –  Gerben Sep 17 '14 at 10:13
    
Hi, thanks for the reply. I got a sort of rudimentary fall detection working. Just wondering if there is any methods in which I can utilize the other two sensors (Gyrometer)/(Magnenometer) to further improve its precision. Much Appreciated –  user4985 Sep 18 '14 at 6:41

1 Answer 1

up vote 3 down vote accepted

Sitting an accelerometer flatly on a bench will produce a value of 1G in one of the 3 axes.

Free fall of an accelerometer (assuming you haven't reached terminal velocity) should read near zero on all 3 axes.

I am not aware of a mode you can set for this, but if you check the values of the 3 axes and all are close to zero, you are probably in a free fall condition.

share|improve this answer
    
Hi, thanks for the reply. I got a sort of rudimentary fall detection working. Just wondering if there is any methods in which I can utilize the other two sensors (Gyrometer)/(Magnenometer) to further improve its precision. Much Appreciated. –  user4985 Sep 18 '14 at 6:32
    
I'm not if the gyro will be of use, given that a falling object may or may not be spinning. –  Jason Sep 19 '14 at 4:33

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.