Movement detection

Comments

• Bruce Bates Posts: 3,045

  2006-03-13 12:57 edited 2006-03-13 12:57

  Hi Arno -
  
  May I ask the exact application, and the specific evironment in which the the board will be? Also, will this be in the area of theft protection, or merely detecting movement?
  
  Just out of curiosity, why are only two directions required, as one would think that three direction movement detection would be more appropriate?
  
  Will this be a "portable" (non line powered or battery powered) application? Does the application have anything to do with a motor vehicle?
  
  A lot may depend on those factors above, and others as well, once we know the specific application. An accelerometer may or may not be the best route to go. In fact, you may need more than one type of sensor to detect both fast and slow movement of the board.
  
  If you would feel more comfortable speaking about it off-list, just send me a PM and I'll send you my email address.
  
  Regards,
  
  Bruce Bates
  
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• arno Posts: 43

  2006-03-13 13:37 edited 2006-03-13 13:37

  Hi Bruce,
  Yes it's gona go in a car (detecting when the car is moved and send a SMS to an operator), so it' gona be a battery powered (not the one in the car).
  
  Why 2 dimensions? You car move in 2 directions only, even if you left it, you still go forward/backward, and (hard) left/right (I mean hard because it's hard to go left or right without the forward/backward movement).
  
  I find some information on the demo kit paper on the page of the memsis 2125 at Parallax web site (chapter 3 'motion detector', and it' look like I find all I need.
  http://www.parallax.com/dl/docs/prod/acc/memsickit.pdf
  
  But still open for any advice on that one.
  
  regards,
  arno
• Bruce Bates Posts: 3,045

  2006-03-13 14:14 edited 2006-03-13 14:14

  Arno -
  
  I'm not sure what your expectations are of this system of yours, or exactly how you're planning to have it work. However, I can think of at least two methods of "removing" an automobile and having it "disappear" (from view) in almost less time than it would take for you to receive your SMS message. One method is by using a tilt-bed car carrier (with a geared up winch) and a fast crew of thieves.
  
  Merely as a reminder, or passing thought, if you use an accelerometer (only) to gauge when the car appears to be "moving" it will probably also sense something or someone merely leaning on the car. This unknown "someone" may be a meter maid or police patrol person placing a parking ticket on the car. Whether it will respond to a heavy wind or rain storm, is something else you will need to gauge for yourself after installation.
  
  Just our of sheer curiosity, since I know nothing about SMS, what happen if your cell phone is busy, when an SMS message is sent?
  
  Regards,
  
  Bruce Bates
  
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• arno Posts: 43

  2006-03-13 14:50 edited 2006-03-13 14:50

  Bruce,
  You almost right with all you observation.
  As for the car disapear, no problem for me it' won't. Since I give you only the half of the system. look on AVL on the net. But to give you a few info here is how it's gona work: the car, move (or appear to move), the system send a SMS to a operator. then the operator open a data connection with a GSM module on the car, this system will then start a GPS receiver, So i will have the info where the car is going (moving map on a PDA or PC). Then after a timeout (30minutes or so)of unmoving status, the Motion detector stop the communication, and all the system go in stanby mode.
  
  As for the sms, it will be stay in queue for as long you ask for it, I think it's something like 24hours.
  
  So if someone bump in my car, or if you touch it enougth to activate the motion detector (that mean bat tunning of it), no problem, I will just have a 30 minutes until it sleep again.
  
  Hope that answer you curiosity [noparse];)[/noparse]
• arno Posts: 43

  2006-03-13 14:51 edited 2006-03-13 14:51

  That the th