Mightyhat as a Home Alarm System

SadE54 · April 05, 2016, 01:06:55 PM

Hi,

I'm currently designing my own wireless home alarm and I'm considering a Mightyhat + RPI3 as the core of the system.
I would embed all the security system in the mega 328 and interface/configuration to the system at the Pi level .
But it seems there's no generic IO access available on the board for a keypad for example :-/
Is there some free IO directly on the mega chip ? I can't find any schematic .

Thnaks in advance !

Felix · April 05, 2016, 01:31:47 PM

Pretty much all the IO are taken when all the buttons and LCD are installed.
You can easily get at least 2 IO (A4, A5) if you skip the 2 tactile buttons next to the LCD. The power button uses 3 IOs (red, green, button). The LCD uses another few.
You have tons of free IO on the Pi itself.
Not sure I see the logic behind putting your "brains" in the keypad itself where it could be disabled. You'd normally want that hidden away. The keypad should be nothing more than just a device to arm/disarm the system.

SadE54 · April 05, 2016, 02:00:03 PM

Yeah , this keypad is more a secured 'wired' one . The system will be hidden. The main keypad for activation / deactivation will be a modified keypad of this type :
http://etiger.com/eu/security/accessories/es-k1a/ with a moteino inside

Felix · April 05, 2016, 02:10:59 PM

Ok in that case what are your requirements for the MHat? Do you still need a keypad on the Pi as well?

SadE54 · April 05, 2016, 02:22:38 PM

Ideally yes, If there's a failure on the wireless one. But I guess I could do without $:-\$
But at least 2 inputs to secure the case of the system like any other home alarm system.
There's a lot on the Pi itself you're right, but I would avoid to mix the secured/core part (the mega) from the services/configuration one (the pi).
It's currently not the perfect solution for my needs, but a near one , especially considering the UPS part
Maybe a future version with a bigger mega ?

Felix · April 05, 2016, 02:33:28 PM

If 1 person buys it, then I can't justify it.
If 100+ people will buy it at something like $10 more then maybe it becomes worth the time and investment.

SadE54 · April 05, 2016, 03:05:09 PM

Anyway, I'm curious about the vision of the users for an 'ideal ' RFM69 RPi hat !

Felix · April 05, 2016, 04:40:29 PM

Quote from: SadE54 on April 05, 2016, 03:05:09 PM
Anyway, I'm curious about the vision of the users for an 'ideal ' RFM69 RPi hat !

I had this project in my mind and on paper and then in development for some time. I kept refining it until I arrived at the current version. Of course, this is my ideal feature set without getting crazy and increasing cost to beyond reasonable. Even so it's got a lot of functions and it's not the easiest to assemble and test. Simple (usability standpoint) is one of the paramount features.
I think it turned out pretty good considering it combines the ability of an ATXRaspi, MightyBoost and Moteino RF gateway (+ other features) all in one compact yet flexible board that allows for the Pi to go in a tight enclosure. That's mainly what I wanted. To some doing it all with discrete components is a good way to learn (but not save). Otherwise a HAT like this is the next best alternative IMO.

SadE54 · April 06, 2016, 03:22:19 AM

Don't get it wrong , you probably did the good choice in terms of designing considering your objectives !
For my project, I will probably go for a little more powerful arduino board , a teensy one , because of the RAM and Flash size.
So I'll use a mighty boost board . For the screen I like this solution : http://nextion.itead.cc/
I hope the mighty boost specs will be enough for the increased consumption of the PI 3 :-/