Deep Sleep NodeMCU with Door Sensor

Question

I have a very simple code of door sensor (magnetic) which gives results in 1 & 0 format. But I want to run the NodeMCU only when a door is open or close. Rest of time I want to keep it in deep sleep mode. Here is my code looks like :

int doorClosed = 1;

#define REED_SWITCH D5

void setup() {
  // put your setup code here, to run once:

  Serial.begin(115200);
  pinMode(BUILTIN_LED, OUTPUT);
  digitalWrite(BUILTIN_LED, HIGH);

  pinMode(REED_SWITCH, INPUT_PULLUP); 
}

void loop() {
  // put your main code here, to run repeatedly

   Serial.println(digitalRead(REED_SWITCH));

    if ((digitalRead(REED_SWITCH) == HIGH) && (doorClosed == 1))
    {
      Serial.println("DOOR OPEN!!");
      doorClosed = 0;
      digitalWrite(BUILTIN_LED, LOW);
      ESP.deepSleep(0); 
    } 
    else if ((digitalRead(REED_SWITCH) == LOW) && (doorClosed == 0))
    {
      Serial.println("DOOR CLOSED!!");
      doorClosed = 1;
      digitalWrite(BUILTIN_LED, HIGH);
      ESP.deepSleep(0); 
    }
    delay(500);
}

Here I am able to put the NodeMCU in deep sleep. But it never wakes up. How can I wake up my chip. After attaching the D0 with RST, I don't event get Serial Logs. I am not sure what kind of behaviour is this. If someone can help me to fix this code will be great!

Thank you!

Answer 1

According to this guide:

The RST pin of the ESP8266 is always HIGH while the ESP8266 is running. However, when the RST pin receives a LOW signal, it restarts the microcontroller.

If you set a Deep Sleep timer with the ESP8266, once the timer ends, GPIO 16 sends a LOW signal. That means that GPIO 16 when connected to RST pin can wake up the ESP8266 every time the timer ends.

The only way to wakes up ESP8266 from deep sleep mode without timer is set a LOW signal on RST pin.

Example without timer:

ESP.deepSleep(0); 

Connect D0 (GPIO 16) to RST is available only when ESP8266 is in sleep mode with timer.

Example with 30sec timer:

ESP.deepSleep(30e6); 

In your case, you can use deep sleep with timer and connect Door sensor to D0 and will act as switch between the RST and D0.

Answer 2

My response is late but herewith my experience that may be of help to others.

NodeMcu in deep sleep will wake-up from external source on receiving a pulse from high to low on the RST pin.

An ADXL345 accelerometer raises an interrupt HIGH on sensing motion and remains high until (I2C) READ to prevent multiple devices from interfering with each other

The following post was instrumental in my finding a solution

https://electronics.stackexchange.com/questions/158015/how-to-turn-continuous-signal-into-a-short-pulse-using-logic-gates