ESP8266 - Motion Sensor - Servo Motor

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

When motion is detected, ESP8266 rotates servo motor to 90 degree
When motion is not detected, ESP8266 rotates servo motor back to 0 degree.

This can be applied in an automation process that triggers actions upon detecting human presence.

Hardware Preparation

1	×	ESP8266 NodeMCU
1	×	Micro USB Cable
1	×	HC-SR501 Motion 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 Motion Sensor

If you are unfamiliar with servo motor and motion sensor (including pinout, functioning, programming, etc.), 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.

The wiring diagram between ESP8266 NodeMCU and Motion Sensor Servo Motor Extra Power

This image is created using Fritzing. Click to enlarge image

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

Initial Setting


Time Delay Adjuster	Screw it in anti-clockwise direction fully.
Detection Range Adjuster	Screw it in clockwise direction fully.
Repeat Trigger Selector	Put jumper as shown on the image.

ESP8266 Code - Motion 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-motion-sensor-servo-motor */ #include <Servo.h> #define MOTION_SENSOR_PIN D7 // The ESP8266 pin connected to motion sensor's pin #define SERVO_PIN D1 // 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_motion_state; // The previous state of motion sensor int motion_state; // The current state of motion sensor void setup() { Serial.begin(9600); // Initialize the Serial to communicate with the Serial Monitor. pinMode(MOTION_SENSOR_PIN, INPUT); // Configure the ESP8266 pin to the input mode servo.attach(SERVO_PIN); // attaches the servo on pin 9 to the servo object servo.write(angle); motion_state = digitalRead(MOTION_SENSOR_PIN); } void loop() { prev_motion_state = motion_state; // save the last state motion_state = digitalRead(MOTION_SENSOR_PIN); // read new state if (motion_state == LOW && prev_motion_state == HIGH) { // pin state change: LOW -> HIGH Serial.println("Motion detected!, rotating servo motor to 90°"); servo.write(90); } else if (motion_state == HIGH && prev_motion_state == LOW) { // pin state change: HIGH -> LOW Serial.println("Motion stopped!, rotating servo motor to 0°"); servo.write(0); } }

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.
Connect your ESP8266 to a computer using a USB cable.
Launch the Arduino IDE, select the appropriate board and port.
Paste the code into the IDE and open it.
Click the Upload button on the IDE to send the code to the ESP8266.
Move your hand in front of the sensor.
Check out the servo motor's movements.

Video Tutorial

Function References

Learn More

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