detect the deceleration of vehicles using BHI160B

[Gideon]

Hello,

I am trying to see how can I get the information about the deceleration of vehicles(things) using BHI160B.

Actually, I have two projects.  One thing is BlackBox for vehicles and small things handling with hands.

Anyway, to do it, I enabled a virtual sensor of linear acceleration and see what happens.

When I move the board back and forth, I can see staring with negative and positive value as below.

1. Can I just use the negative and positive for catching moving direction?

2. As you can see the value of speed is low, so it won't be easy to detect it(it's only my opinion.).  If you have any idea about that, please, let me know.

Please, help.

Test video Link: https://photos.app.goo.gl/tYWdrHN2zg6Pfxgi6

 

[Vincent · Accepted solution]

First, let's discuss about the deacceleration of objects which is common for two projects: 

1.  when object is in still position,  then move the objects along with one axis's negative direction,  we can sure device is moving towards that direction. 

2. When object is moving towards one direction at constent speed,  when negative acceleration data found from sensor, means the objects gets deaccelerated and slow down.  Then it can stops to a certain lower constent speed of fully stop.   During this, object still moves towards same direction

3. Depend on your use case,  which senario is focused?  

4. if you only care about the deacceleration, then both should be OK.  if you also want to know the motion direction,  then you need to know the initial speed first. 

Second,  let's discuss the difference between two projects:

1. for vehicle,  the acceleration should be easy to detected.  it should always be higher than the smallest resolution (0.061mg under 2G range and noise at 1.8mg @200Hz according to datasheet)   which sensor can detect.

2. for hand, if hand movement is very slow and steady,  then it may not able to detect the acceleration output.  

[Gideon]

Hi Vincent,

3. Depend on your use case,  which senario is focused?  

=> I don't have details yet.

I understand the other comments. Thanks for your help.