a16 as basis for a security system

[admin]

I already have an 8x8 matrix keypad that I was planning to connect to some of the digital inputs, for arming/disarming the alarm.

Not sure that I'd have enough GPIO's for this, but is there a simple means of connecting a small 3.5" TFT display?

(I submitted a post just confirming how to connect everything, but it said the message had to be approved by an admin)

i think you can use a serial HMI displayer, such as Nextion Displayer. Conect board by RS485 port.