{"id":40731,"date":"2021-02-08T18:03:08","date_gmt":"2021-02-08T10:03:08","guid":{"rendered":"\/blog\/?p=40731"},"modified":"2021-02-18T13:38:06","modified_gmt":"2021-02-18T05:38:06","slug":"wio-terminal-arduino-smart-doorbell-with-code","status":"publish","type":"post","link":"https:\/\/www.seeedstudio.com\/blog\/2021\/02\/08\/wio-terminal-arduino-smart-doorbell-with-code\/","title":{"rendered":"Wio Terminal: Arduino Smart Doorbell (with Code!)"},"content":{"rendered":"\n

In this step by step tutorial, learn how to create your very own Arduino Smart Doorbell with your Wio Terminal! This project builds a doorbell that automatically detects the presence of movement, then notifies you on your mobile phone wherever you are. You can also follow along with any Arduino-compatible development board.<\/p>\n\n\n\n

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Introduction to the Smart Doorbell Project<\/strong><\/h2>\n\n\n\n
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There are many reasons why you might want a smart doorbell over the conventional one. For example, you might have a baby in your home and you don\u2019t want your dog to bark and wake her up every time a visitor comes by. Or, you might simply want to know when there are visitors when you aren\u2019t home!<\/p>\n\n\n\n

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Whatever the case, we want our Arduino smart doorbell to be able to do two key things:<\/p>\n\n\n\n

  1. Automatically detect human presence<\/li>
  2. Discreetly notify the user of that presence<\/li><\/ol>\n\n\n\n
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    To achieve this, we will make use of passive infrared sensors to detect motion. For the IoT side of things, there are many platforms that we can use, such as Microsoft Azure IoT and Google Cloud Platform. After some experimentation, however, I\u2019ve decided to use Blynk for this project since it is easy to set up and also provides a readily customisable mobile application interface!<\/p>\n\n\n\n

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    Passive Infrared (PIR) Motion Sensors<\/strong><\/h2>\n\n\n\n
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    Since PIR sensors are at the core of this project, it\u2019s worth taking some time to understand how they work.<\/p>\n\n\n\n

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    Infrared Light<\/strong><\/h3>\n\n\n\n
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    First of all, infrared light<\/a> is simply a type of light that is invisible to the human eye. IR is all around us, emitted by all living things that give off heat. They are also used in many electronic applications, such as sending communication signals and thermal imaging.<\/p>\n\n\n\n

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    Source: Circuit Basics<\/figcaption><\/figure><\/div>\n\n\n\n
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    PIR Sensor: Principle of Operation<\/strong><\/h3>\n\n\n\n
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    A PIR sensor consists of two slots that each contain IR sensitive material.<\/p>\n\n\n\n

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    Source: Last Minute Engineers<\/figcaption><\/figure><\/div>\n\n\n\n
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    When an infrared-emitting body such as a human passes by, it will first intercept one of the IR slots, which causes a positive differential relative to the other IR slot. When the human then leaves the detecting area, the opposite occurs and a negative differential is created. The resulting signal is then detected collectively to produce a \u201cHIGH\u201d output.<\/p>\n\n\n\n

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    Source: Last Minute Engineers<\/figcaption><\/figure><\/div>\n\n\n\n
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    It\u2019s important to understand that it is change<\/em><\/strong> that generates a positive output in our PIR sensor. If an infrared-emitting object remained still in the detecting area, our PIR sensor would eventually output \u201cLOW\u201d!<\/p>\n\n\n\n

    Typically, PIR sensors are covered by a lens known as a Fresnel lens. This lens focuses IR waves from the surroundings onto the sensor. Now, instead of a detecting area of two blocks, we can cover a much wider area instead!<\/p>\n\n\n\n

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    Bringing the Wio Terminal Online with Blynk<\/strong><\/h2>\n\n\n\n
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    When our Wio Terminal detects motion via the PIR Sensor, we want to receive a notification for it remotely. To do this, we\u2019ll use Blynk.<\/p>\n\n\n\n

    Blynk is an IoT platform that allows us to quickly build IoT applications regardless of what hardware we are using. It can also be used for device management, data analytics and machine learning, but today we\u2019ll simply use it to receive messages from our Wio Terminal, and to remotely toggle some settings.<\/p>\n\n\n\n

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    Source: Blynk<\/figcaption><\/figure><\/div>\n\n\n\n

    Although Blynk will cost enterprises who want to use it to implement IoT on a large scale, their Developer Plan is free for individual use to build personal projects which is sufficient for today\u2019s purpose.<\/p>\n\n\n\n

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    Platform Introduction: Wio Terminal<\/strong><\/h2>\n\n\n\n
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    Today\u2019s tutorial will be done with a Wio Terminal and the Grove Mini PIR Motion Sensor<\/a>!<\/p>\n\n\n\n

    The Wio Terminal is a fully integrated microcontroller development platform that supports Arduino and MicroPython. It carries Bluetooth, Wi-Fi connectivity, and comes with an LCD screen, onboard IMU, microphone, buzzer, light sensor and infrared emitter. The Wio Terminal also features two multifunctional Grove ports which can be used to interface easily with plug-and-play Grove modules.<\/p>\n\n\n\n

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    The Wio Terminal is a great one-stop solution for today\u2019s project. Since we can simply make use of the inbuilt WiFi and plug our PIR sensor in via Grove, we\u2019ve eliminated the need for soldering or dealing with messy wires. We can even combine it with its dedicated battery chassis<\/a> to make our doorbell a mobile and conveniently wall-mountable solution!<\/p>\n\n\n\n

    Naturally, you can follow along with this tutorial with any other Arduino board and PIR Sensor, but you\u2019ll have to work a little harder to get the wiring done!<\/p>\n\n\n\n

    You can pick up a Wio Terminal from the Seeed Online Store<\/a>.<\/p>\n\n\n\n

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    Note: While I\u2019ve chosen the Grove Mini PIR Motion Sensor for its compact size and low cost, feel free to choose from the following Grove PIR Motion Sensor modules. Some of them will offer additional functionality such as distance measurement and adjustable holding times.<\/p>\n\n\n\n