Security System Gives You A Call When It Senses Intruders


[Dimitris] decided to build a homemade alarm system, but instead of triggering a siren, sending an SMS message, or Tweeting about an intrusion, he preferred that his system call him when there was trouble afoot. He says that he preferred a call over text messaging because there are no charges associated with the call if the recipient does not pick up the line, which is not the case with SMS.

The system is based around an off the shelf motion detector that was hacked to work with an old mobile phone. The motion detector originally triggered a siren, but he stripped out the speaker and wired it to a bare bones Arduino board he constructed. The Arduino was in turn connected to the serial port of an unused Ericssson T10s mobile phone. This allows the Arduino to call his mobile phone whenever the motion detector senses movement.

The system looks to be quite useful, and while [Dimitris] didn’t include all of the code he used, he says others should be able to replicate his work without too much trouble.

13 thoughts on “Security System Gives You A Call When It Senses Intruders

  1. Mine already does this from the factory, most alarms made in the past 5 years have this built in, and in fact zone-minder will text me when it senses someone walking by one of the outdoor cameras.

    The tricky part with most home alarm systems is getting past the installer password that the jerks that installed it set.

  2. No, the biggest problem with commercially made alarm systems is that they are standardized and they put the brand name on your lawn and windows. Everyone who has ever installed the current brinks model can disarm it…and once one scumbag knows, it is only a matter of time before they all do. There is certainly an advantage to making an alarm that no one else knows the nature of.

    Cut a wire here or set a signal jammer to a specific frequency and a commercial alarm is disabled…a DIY alarm is an unknown (unless you post the instructions online).

  3. I did practically the same thing with my car alarm before they could page you too, it had an aux out and I interfaced it with an old mobile keypad to do a speeddial to my mobile. Worked a treat but came to the conclusion that if it went off I’d never be able to get to it in time anyway so there was no point lol.

  4. Interesting reuse of an old cell phone. However you can get pretty cheap GSM m2m modules. Also you can get decently cheap m2m data plans (especially if your data usage is low). Then you can just pump it right over the internet… No voice or SMS used. Probably cheaper than anything you could do voice wise.

  5. I think the point is you don’t need to communicate with your alarm, the fact that it rings you means you know it’s going off and that doesn’t cost you at all. Free phone, SIMs are often free, free enhancement(?)

  6. I recently thought about doing this with a doorbell, but didn’t seriously think it through because it would be pointless. But, someone presses the doorbell, you get a call, you talk to the person at your door if you’re not home. Could be interfaced to a cheap computer running Skype (if you have Skype on your phone) to avoid big charges. But like I said, pointless, I don’t think anything bad has ever happened to me due to missing a house call other than I’ve missed a delivery, but they wouldn’t be able to leave it at your house just because you spoke to them.

    I might just do it anyway.

    Also, this must have been really easy to do. Simple but effective is always good. I’m pretty sure I’ll make my own security system when I need one. As it is, a big dog (Dobermann) is a good substitute, even if he is getting on a bit. Even simpler than this hack, too…

  7. Heck if you’re a lung cancer get the checkups. That is unless you really don’t care. I remember when I was a kid there were cigarettes called death. They had a skull and crossbones on them. At least it’s honest.

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