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Piggy backing off existing devices

PostPosted: Tue Nov 24, 2015 9:57 am
by SirKnight
I have come up with this circuit that I plan on using to add wifi to some of my existing battery powered devices. I think it would be an easily adaptable circuit for both input and output. Other then the cases I've described below any of the GPIOs could be used to monitor an input as well once it was started up.

I fine with the software side of things and I have tried this out on a breadboard and verified that the circuit works, however I would appreaciate any feedback on the electronics side, is there any thing I am doing dangerously, overly inefficienty, or stupidly? Are there any potential problems that anyone sees? The parts I am using are parts I have on hand, I realize there may be better transistors to use ect.

Benifits of piggy backing off existing devices.
-Already have low battery alarms built in
-Already have power supply and enclosure

Case 1: Water Detector (GPIO_5 isn't used, Just an email notification)
-ESP Starts up when it is activated but a +5V that is present when the Alarm goes off
-Sets GPIO_4 HIGH to keep ESP active till we are done with it
-Connects to WiFi and sends an email
-If the alarm stops we send another email then set GPIO_4 LOW and the ESP shuts down

Case 2: NFC door lock (GPIO_5 is used as an output)
-ESP Start up when lock is activated by the button on the lock (piggy backing off the LED circuit that lights up)
-Sets GPIO_5 HIGH to keep the ESP active for a set amount of time where it connects to wifi and checks a url for a valid unlock code
-If it sees a valid code it sets GPIO_5 HIGH then LOW which activates the switch on the door lock
-Set GPIO_4 LOW and shutdown the ESP

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