Published March 31, 2021 © CC BY-NC-SA

Motion Detector With Blynk Notifications

How to make Motion Detector With Blynk Notifications (WeMos D1 Mini + HC-SR04)

BeginnerFull instructions provided1 hour612

Things used in this project

Hardware components

Espressif Wemos D1 Mini

SparkFun Ultrasonic Sensor - HC-SR04

Software apps and online services

Arduino IDE

Story

I wanted to make a motion detector that would notify me every time my garage door is opened. I was playing with PIR sensor for a while but after having some setup issues (sensitivity x time) I decided to use the HC-SR04 sensor instead...and it works like a charm. The idea is simple: you setup the detector so when the door (or window - depends on how you want to use it) is opened, it gets in the way of the sensor so the measured distance is changed. The advantage using the UltraSonic sensor instead of PIR huge. It can't be triggered with light or mosquitoes which was the main reason I didn't want to use the PIR.

A huge shout out to NextPCB for sponsoring this project. They are a PCB manufacturer, China PCB manufacturer which is also capable of doing PCB assembly.

What you will need:

WeMos D1 mini board - (other boards are possible - just note that e.g. NodeMCU ESP-12E V1.0 gives out only 3.3V and the HC-SR04 sensor needs 5V)
HC-SR04+ Ultrasonic sensor - - (using "+" as it can operate on 3.3V)
Blynk app(if you are new to Blynk and using iOS device, you will need to borrow an Android phone for setting up the notifications)
Breadboard or soldering iron
Wires
Computer with Arduino IDE installed

Step 1: Getting the Parts Together

I heard about people having issues when powering the HC-SR04 sensor from the board. It works fine for me, but the safest way to prevent this is to use HC-SR04P (or "+"), which has an input range of 3 - 5.5v

Connections (see the diagram)

WeMos D1 --> HC-SR04(P)

5V --> VCC

G --> GND

D6 --> Echo

D7 --> Trig

Step 2: Blynk Setup

Download the Blynk app

For those who don't know what Blynk is, it is a Platform with iOS and Android apps to controlArduino, Raspberry Pi and the likes over the Internet. It's a digital dashboard where you can build a graphic interface for your project by simply dragging and dropping widgets.

Let's start on Andorid device:

Download the Blynk app
Sign up or login (if you already have an account)
Tap "+" to create New Project
Give the project a name and select device you are using (in our case it is ESP8266) and tap "Create"
You will receive an Authentication token in you mail box, we are going to need it later
On the Blynk Project page tap "+" to add notification widget (if this is your first Blynk project, you should have enough energy to buy it) and set it up as you wish. I use settings as displayed on the screenshot.
In the project settings (nut icon on the top) "Send app connected command" to ON.
Close the settings and hit the Play button

Now you can login to Blynk app on your iOS device as well and you should see the project with the notification widget.

Step 3: The Code

Now it is time to upload the code to our board.

Open the *.ino file in Arduino IDE
Connect the WeMos board to your computer
In Tools select the WeMos D1 R2 & mini board
Adjust the following:

char auth[] = "Your authentication token from your mail box goes here";char ssid[] = "Your WiFi name";char pass[] = "Your WiFi password";

Also, you can change the range, where you want to be notified (default is set to 1 - 49cm)

if (0 < distance && distance < 50) {

Hit Upload

Congratulations! If everything was set right, you should now receive your first notification!

Step 4: Summary

There are three notifications you will be receiving now. The first is telling you, that the Detector was successfully connected to your WiFi, the second notification you will be receiving is when something gets within your setup range. And the third when your Detector is disconnected due to connection or power supply issues.

The modifications you can make to this project are endless. You can setup more notifications for different ranges (Just be aware that Blynk allows notifications after 15s at least). Use different sensors, etc.

About NEXTPCB

NextPCB is one of the most experienced PCB manufacturers in China, has specialized in the PCB and assembly industry for over 15 years, providing some of the most innovative printed circuit board with assembly technologies in terms of the highest quality standards, fastest delivery turnaround as fast as 24hours, lowest manufacturer direct prices, and the most dedicated customer service in the industry. You can count on NextPCB to meet your needs, from the simplest boards to the most complex designs for small quantity and large-scale production.

I hope you like this project, if you do, please vote for me and leave a comment/suggestion...I will be happy to get some insight from the others!

Code

Code

#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>

char auth[] = "Your Blynk token"; //Blynk token
char ssid[] = "SSID"; //Your WiFI SSID
char pass[] = "WiFi password"; //Your Wifi password

// Define pin numbers
const int echoPin = D6;
const int trigPin = D7;

// Define variables
long duration;
int distance;
int saveDis = 0;

SimpleTimer timer;

void sensorRead() {
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);  // Reads the echoPin, returns the sound wave travel time in microseconds
  saveDis = distance;                 // Save the distance to compare with the next value (for Blynk notification)
  distance = duration * 0.034 / 2;    // Calculating the distance

  Serial.println("Distance: " + String(distance) + "cm");  // Prints the distance on the Serial Monitor
  // Set Blynk notification for given range (in this case between 1-49cm)
  if (0 < distance && distance < 50) {
    Blynk.notify("Garage: Distance changed from " + String(saveDis) + "cm to " + String(distance) + "cm!");
  }
}
  void setup() {
    Blynk.begin(auth, ssid, pass);
    Blynk.notify("Garage: Connected to: " + String(ssid));
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);
    Serial.begin(115200);
    Serial.println("Motion Detector initializing...");
    timer.setInterval(1000L, sensorRead);
  }

  void loop() {
    Blynk.run();
    timer.run();
  }

Credits

NextPCB

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Motion Detector With Blynk Notifications

Things used in this project

Hardware components

Software apps and online services

Story

Step 1: Getting the Parts Together

Step 2: Blynk Setup

Step 4: Summary

About NEXTPCB

Schematics

Schematics

Code

Code

Credits

NextPCB

Comments

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Motion Detector With Blynk Notifications

Motion Detector With Blynk Notifications

Things used in this project

Hardware components

Software apps and online services

Story

Step 1: Getting the Parts Together

Step 2: Blynk Setup

Step 4: Summary

About NEXTPCB

Schematics

Schematics

Code

Code

Credits

NextPCB

Comments

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