Detecting rocking motion

Solar2D General Questions/Discussion
#1

I am trying to figure out how I can go about detecting a quick rocking motion of the device without too much luck. Basically, there are two motions I want to detect; a rocking of the device away from the user ( quick tilt down then back up) and rocking towards the user (quick tilt up and then back down).

I have tried using the event.yInstant property of an accelerometer runtime event, but it doesn’t seem to be giving me what I am looking for.

Any advice or direction is greatly appreciated.

All the best,
Alan

#2

Have you tried the Gravity API? I used that to implement something similar to what you’re describing.

#3

I have not.  Where can I find info about this?

#4

Here’s the accelerometer api. The Gravity documentation is above the Instant entries.

#5

Thanks for that.  

I was trying to do this with the yGravity at first.  The problem that I was running into was establishing the baseline from which to measure the changes.  For example, the user is holding their device at say a 25 degree angle when the game is started.  I would want to check for changes based on rocking from that angle.  I just couldn’t figure a way to get that start position and then measure based off of that.  Does that make sense?

#6

You might be able to store the initial yGravity value and compare the values being collected against that. Something like this:

 local initGravY local function initGrav( event ) initGravY = event.yGravity Runtime:removeEventListener( "accelerometer", initGrav ) print( event.name, event.xGravity, event.yGravity, event.zGravity ) end local function onAccelerate( event )          if initGravY \> event.yGravity then ​ print("DO SOMETHING HERE") end print( event.name, event.xGravity, event.yGravity, event.zGravity ) end Runtime:addEventListener( "accelerometer", onAccelerate ) Runtime:addEventListener( "accelerometer", initGrav )

Not tested, YMMV, yadda yadda.

#7

Looks good.  I’ll try that out.  Thanks!

#8

Have you tried the Gravity API? I used that to implement something similar to what you’re describing.

#9

I have not.  Where can I find info about this?

#10

Here’s the accelerometer api. The Gravity documentation is above the Instant entries.

#11

Thanks for that.  

I was trying to do this with the yGravity at first.  The problem that I was running into was establishing the baseline from which to measure the changes.  For example, the user is holding their device at say a 25 degree angle when the game is started.  I would want to check for changes based on rocking from that angle.  I just couldn’t figure a way to get that start position and then measure based off of that.  Does that make sense?

#12

You might be able to store the initial yGravity value and compare the values being collected against that. Something like this:

 local initGravY local function initGrav( event ) initGravY = event.yGravity Runtime:removeEventListener( "accelerometer", initGrav ) print( event.name, event.xGravity, event.yGravity, event.zGravity ) end local function onAccelerate( event )          if initGravY \> event.yGravity then ​ print("DO SOMETHING HERE") end print( event.name, event.xGravity, event.yGravity, event.zGravity ) end Runtime:addEventListener( "accelerometer", onAccelerate ) Runtime:addEventListener( "accelerometer", initGrav )

Not tested, YMMV, yadda yadda.

#13

Looks good.  I’ll try that out.  Thanks!