SENSORS/ACTUATORS

ESP8266 - Door Sensor - Servo Motor

This tutorial instructs you how to use ESP8266 and door sensor to control servo motor. In detail:

When the door is open, ESP8266 rotates servo motor to 90 degree
Should the door open again, ESP8266s rotates servo motor back to 0 degree.

The above process are repeated infinitely.

Hardware Preparation

1	×	ESP8266 NodeMCU
1	×	Micro USB Cable
1	×	Door Sensor
1	×	Servo Motor
1	×	Jumper Wires
1	×	(Optional) 5V Power Adapter for ESP8266
1	×	(Optional) ESP8266 Screw Terminal Adapter

Or you can buy the following sensor kit:

DIYables Sensor Kit 30 types, 69 units

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Overview of Servo Motor and Door Sensor

If you are unfamiliar with servo motor and door sensor (including pinout, operation, and programming), the following tutorials can help:

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

See more in ESP8266's pinout and how to supply power to the ESP8266 and other components.

Please note that the wiring diagram shown above is only suitable for a servo motor with low torque. In case the motor vibrates instead of rotating, an external power source must be utilized to provide more power for the servo motor. The below demonstrates the wiring diagram with an external power source for servo motor.

TO BE ADD IMAGE

Please do not forget to connect GND of the external power to GND of ESP8266.

ESP8266 Code - Door Sensor Controls Servo Motor

/* * This ESP8266 NodeMCU code was developed by newbiely.com * * This ESP8266 NodeMCU code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/esp8266/esp8266-door-sensor-servo-motor */ #include <Servo.h> const int DOOR_SENSOR_PIN = 7; // The ESP8266 pin connected to door sensor's pin const int SERVO_PIN = 9; // The ESP8266 pin connected to servo motor's pin Servo servo; // create servo object to control a servo int angle = 0; // The current angle of servo motor int prev_door_state; // The previous state of door sensor int door_state; // The current state of door sensor void setup() { Serial.begin(9600); // Initialize the Serial to communicate with the Serial Monitor. pinMode(DOOR_SENSOR_PIN, INPUT_PULLUP); // set arduino pin to input pull-up mode servo.attach(SERVO_PIN); // attaches the servo on pin 9 to the servo object servo.write(angle); door_state = digitalRead(DOOR_SENSOR_PIN); } void loop() { prev_door_state = door_state; // save the last state door_state = digitalRead(DOOR_SENSOR_PIN); // read new state if(prev_door_state == LOW && door_state == HIGH) { Serial.println("The door-opening event is detected"); // change angle of servo motor if(angle == 0) angle = 90; else if(angle == 90) angle = 0; // rotate the servo motor to the angle position servo.write(angle); } }

Detailed Instructions

To get started with ESP8266 on Arduino IDE, follow these steps:

Check out the how to setup environment for ESP8266 on Arduino IDE tutorial if this is your first time using ESP8266.
Wire the components as shown in the diagram.
Connect the ESP8266 board to your computer using a USB cable.
Open Arduino IDE on your computer.
Choose the correct ESP8266 board, such as (e.g. NodeMCU 1.0 (ESP-12E Module)), and its respective COM port.
Attach ESP8266 to the computer using a USB cable.
Open the Arduino IDE, select the correct board and port.
Copy the code above and open it in the Arduino IDE.
Click the Upload button on the Arduino IDE to compile and upload the code to the ESP8266.
Bring the magnet close to the reed switch and then move it away from the reed switch. Do this multiple times.
Check out the servo motor angle change.

Video Tutorial

Function References

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