Burglar Alarm / automation / AI2


I'm looking at the options for building an integrated system for my garage. I already have a home network, server, WiFi, uno, mega, pi etc.

System requirements:

Independent burglar alarm that does not rely on an an OS or WiFi, which will continue to work in the event of power/network outage (battery backup). Set with wired keypad.

Which can also be monitored/set from 1) a phone (local WiFi and remote 5g) with an app not a Web page, using a secure protocol. 2) local touch screen.

Phone app and Web page need to control this with secondary system that controls lighting and motorised doors / cameras, plus other inputs/outputs.

Happy to build this from the ground up or use std practice/tools for iot.

Only.want to use wifi/5g where absolutely needed (like mobile phone) but run power/cat6/alarm cables where needed.

Thoughts so far:

Https needs a pi.
Pi needs to talk to multiple arduinos
Pi talks to 1 (ethernet, serial, other?)or 2 arduinos via
Rs485 (need to consider modbus?)
AI2 is proving easy to use (I like the tinydb :grinning: )
I'm good with basic sql, html, css, javascript, xml, json)
Happy to learn python.

Would like to integrate lights with alexa/google home

1st stab at architecture:-

alarm = mega
Lights & other i/o = uno
talk to each other via rs485?
Pi running secure Web server talks to mega over serial USB, or should I consider rs485 ( distance is <1m) or some tcp/ip protocol?
Pi presents html Web pages locally
Android mobile app connects securely using websockets to Pi?

Any comments / guidance much appreciated :slight_smile:

If you are going to run a RPi. then have the MCU's connect to the RPI through MQTT. I use Python program on the RPi as traffic manager.

I have the RPi send data to my web site's dB.

You could have a look at commercial alarm panels rather than re invent the wheel , would make life easier and include the features you want at minimal cost .

Agreed. My telecom house alarm is very feature rich, but this is more about fun/leaning/pain. Even if takes years to get it right.

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I guess you are not attempting to construct an alarm system that automatically calls the police or fire depts!

Break your project down into small steps. Accomplish one then move on to another. Everything you describe can be done with Arduino devices, I really don't see the need for a Pi. You can run a web server on a $1 ESP board.

You aren't really painting a comprehensive picture of what you want to accomplish, but a lot sounds like 1980's technology.

You don't want to depend on an OS? What do you think runs on the Pi?

Why are you afraid of WiFi?

Does arduino support https?

Most Arduinos don't have WiFi, and I haven't used any that do. If I need WiFi, I use a board that already has WiFi on it, like the Wemos D1 Mini or the NodeMCU.

HTTPS on an ESP board

Since nothing on my local net is exposed to the outside world, I've only used HTTP.

Thanks for that... ive spent hours looking at MQTT. Do you use mosquitto and Home assistant by any chance?

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