MicroPython Forum (Archive)

I'm pretty sure that the window break detectors were a purely mechanical device. Normal alarm system practice is to use a normally closed contact.

MostlyHarmless wrote: ↑

Tue Jan 07, 2020 4:06 pm

...I think a vibration sensor should not have more demand for power, so an 8266 deep sleep design should be possible...

Alas I have no experience with ESP8266 deepsleep. You can wake via a timer alarm, but can you wake on a pin change?

pythoncoder wrote: ↑

Tue Jan 07, 2020 6:29 pm

I'm pretty sure that the window break detectors were a purely mechanical device. Normal alarm system practice is to use a normally closed contact.

MostlyHarmless wrote: ↑

Tue Jan 07, 2020 4:06 pm

...I think a vibration sensor should not have more demand for power, so an 8266 deep sleep design should be possible...

Alas I have no experience with ESP8266 deepsleep. You can wake via a timer alarm, but can you wake on a pin change?

There should be at least one way. From machine.deepsleep() the device boots on RST's rising edge. WAKE (GPIO16) is usually wired some way to it, which is how the alarm works. Unless I am reading all this wrong.


Regards, Jan

If you want to have better security, make sure that your electronics are protected by a time lock, that can only be opened when you are around.

Intermatic makes configurable 365 day timers, quite sophisticated, but also quite expensive...

safetyfactorman wrote: ↑

Tue Jan 07, 2020 11:38 pm

If you want to have better security ...

Security has been, and always will be, about creating an imbalance between the possible gain and the effort plus risk involved to get something. There is no unbreakable lock and there is no encryption that cannot be deciphered. It is just a matter of how much will it cost or what other risks are involved in getting it compared to how bad you want whatever it is.

no encryption that cannot be deciphered

Apart from a one-time pad.

kevinkk525 wrote: ↑

Tue Jan 07, 2020 7:05 am

And if you are very paranoid, you'd want to avoid using anything relying on wireless signals as those could be jammed, making your automations not triggering, except for those that run on the same controller.

Easy fix: Every device should send a "alive" signal to server. Think the whole system should use MQTT. So the device can be just a small ESP8266 with limited resources...

I also realize that a simple solution does not really offer much protection.

The biggest protection is probably just the fact that a attacker can see a device sticking to the window pane from the outside and that there is a LED blinking there. Maybe the attacker then thinks about it and prefers to go on to the next house where there is no indication for an alarm system

The whole thing is just more of a hobby project. Nevertheless the time to realize it should be manageable. I have some other hobbies, too.

pythoncoder wrote: ↑

Wed Jan 08, 2020 7:24 am

no encryption that cannot be deciphered

Apart from a one-time pad.

Well, in that case we go with lead-pipe decoding. You get someone who knows the cipher, drug them and pummel them with a lead pipe until they tell you the secret. Its ugly, but it works.

A quick web search for 'glass break sensor' shows that there are already low-cost products available to do this, either with the sensor and alarm all in one unit or with a sensor that communicates by low-power radio (e.g. 433 MHz) to a central alarm system.

What's your objective - to set up your own security system, to develop a commercial product, to find a project for your own interest, or something else?

Just for fun

Would be great to buy a ready to use devices and flash micropython on it.

Maybe the Adafruit CLUE device can fit, if it's cheap and if there is a easy way to use an independent power supply:

https://www.adafruit.com/clue

It has these sensors: