Door Prop Monitoring Application - Need Help!

Projects General Guidance
1

Greetings from an Arduino virgin!

I am looking to design a door prop monitoring solution for a commercial building with 16 doors and believe this could be nicely accomplished with Arduino technologies. The end user wants to be notified if any of their exterior doors are propped open for 30+ seconds via SMS text or email (or both).

The sensors are simple Normally-Closed contacts and of course I need to accommodate as many as 16 sensors and have 16 individual timers to monitor them individually.

I am seeking assistance for what hardware I should be pursuing for this application and would really appreciate any suggestions. There are SO many choices it appears with my new and limited knowledge of Arduino.

Thanks!! Michael S.
Weston, FL

2

Simple switch contacts from a pin to Gnd may be read correctly by an Arduino, a strong pullup resistor may be needed at the Arduino end. (like 1K to 5V).

byte pin2 = 2;
void setup():
pinMode (pin2, INPUT_PULLUP); // add external pullup as well, from the pin to 5V. The pin will connect to one side of the switch, and the other side will connect to Gnd.
Serial.begin (9600); // show results on Serial Monitor
}
void loop(){
if (digitalRead(pin2) == LOW){
  Serial.println("Switch is closed");
  }
if (digitalRead(pin2) == HIGH){
  Serial.println("Switch is open");
  }
  delay (200); // dumb delay for testing switch reading, keeps it to 5x a second
}

You'd have to do a test from the Arduino to the farthest door location and see if that will suffice, or if something more active would be required.

A poster in a different thread said "so i've written a quite a big piece of code that reads and writes from an SD card. controls some IO and sends SMS when an alarm occurs.

I am using the FONA library from Adafruit, where i use hardware Serial to connect with a SIM800L module."

So you could into that as well at Adafruit.com.

3

mspring:
I am looking to design a door prop monitoring solution for a commercial building with 16 doors and believe this could be nicely accomplished with Arduino technologies. The end user wants to be notified if any of their exterior doors are propped open for 30+ seconds via SMS text or email (or both).

If there is easy access to WiFi then an ESP8266 at each door might be the simplest solution (or an ESP32).

...R