Leave home safely: Automatic open window checks with Home Assistant & sensors

Expected Reading Time: 9 minutes

Have you ever set off for work only to suddenly wonder if you've left a window open? This little uncertainty can linger in the back of your mind throughout the day and cause stress. But don't worry - with Home Assistant and the right sensors, this problem will be a thing of the past. In this article, we'll show you how to make your home smarter and never again forget an open window or door when you leave.

What is Home Assistant?

Before we dive deep into the subject, let's briefly explain Home Assistant. Home Assistant is an open-source home automation software that centrally controls all your smart devices. It runs on a Raspberry Pi or similar device and gives you the freedom to design your smart home exactly how you want it, without being tied to the ecosystems of big companies.

One of the biggest advantages of Home Assistant is its flexibility and customizability. Users can create complex automations and scenarios tailored to specific needs and preferences. Home Assistant allows you to configure everything from simple tasks such as turning off all lights when no one is home to complex security systems that are activated when you are away, and offers an impressive depth of configuration options. The platform also focuses heavily on data protection and local control, so your data stays on your own network and you don't have to send it to external cloud services.

Thanks to its active community and constant development through contributions from developers from all over the world, Home Assistant is constantly being improved and expanded. The platform also offers a dashboard, called Lovelace, which is fully customizable and allows you to control your smart home in an intuitive and visually appealing way. Whether you're a tech enthusiast looking for maximum control over your smart home or simply a reliable solution for everyday tasks, Home Assistant offers the flexibility, security and power to make your vision a reality.

Choosing the right sensors

The first step towards an automatic window check is selecting the right sensors. Door/window sensors that detect whether a window is open or closed are particularly suitable for windows. These sensors consist of two parts: a magnet and a sensor. The sensor is attached to the window frame and the magnet to the moving part of the window. When the window is closed, the two parts are next to each other and the sensor is inactive. As soon as you open the window, the distance between the sensor and magnet interrupts the circuit and the sensor sends a signal.

When choosing door and window sensors, you are faced with a variety of options that differ in technology, range, battery life and compatibility. A popular choice for smart home systems are Zigbee-based sensors. Zigbee is an open global standard known for its reliability and, above all, its extended range.

Unlike Wi-Fi, which can have signal problems in larger homes or across multiple floors, Zigbee's mesh network principle allows each device to communicate with other devices and relay signals. This significantly increases the range and stability of the network.

Zigbee devices are therefore particularly suitable for use in smart homes, as they can guarantee seamless coverage even if sensors are installed far away from the main hub. By choosing Zigbee sensors for your home assistant system, you ensure that you receive reliable notifications no matter where in the house a window is opened. You also reduce the likelihood of signals being lost due to distance or structural obstructions in the home.

Integration in Home Assistant

Once you've selected and installed your sensors, it's time to connect them to Home Assistant. The exact procedure depends on the sensor, but most modern sensors use Z-Wave, Zigbee or Wi-Fi to communicate. In Home Assistant, you can use the integration options to browse your network and add the sensors. Once installed, you can monitor the status of each window in real time via the Home Assistant dashboard.

Zigbee currently the ideal solution

The Zigbee2MQTT tool is a powerful solution for integrating Zigbee devices into Home Assistant. This makes it possible to connect Zigbee devices directly to Home Assistant without the need for proprietary gateways. To use Zigbee2MQTT, you first need a Zigbee-enabled USB stick that acts as a bridge between your Zigbee devices and the MQTT server. MQTT stands for Message Queuing Telemetry Transport and is an open network protocol that is used for communication between devices.

Once you have connected the USB stick to your Home Assistant system, you will need to install and configure Zigbee2MQTT. This process includes setting up the MQTT server if you don't already have one in operation and configuring Zigbee2MQTT to communicate with this server. The configuration allows you to pair, manage and control devices by sending commands and receiving status updates via the MQTT protocol.

Using Zigbee2MQTT has several advantages. It not only extends the compatibility of your Home Assistant system with a wide range of Zigbee devices, but also provides improved stability and flexibility in your smart home network. Direct communication between the devices and Home Assistant via MQTT allows you to create detailed automations and scenarios tailored to your needs. Zigbee2MQTT also allows you to retain complete control over your data, as there is no dependency on cloud services or external gateways.

Setting up Zigbee2MQTT may seem complex at first, but the investment in time and the low hardware costs quickly pay off thanks to the expanded possibilities and greater independence of your smart home system.

Create automations

Now that everything is set up, comes the magic part: automation. You can configure Home Assistant to notify you if a window is open when you leave the house. Here's a simple example of what such automation could look like:

1. Trigger: You activate the "leaving the house" scenario, e.g. by pressing a button or by leaving the geofencing area around your house.
2. Condition: Home Assistant checks the status of all window sensors.
3. Action: If a window is open, Home Assistant sends a notification to your smartphone or sets off an acoustic alarm in your home.

Automation as code

alias: Monitor - Windows/doors still open
description: ""
trigger:
  - platform: state
    entity_id:
      - alarm_control_panel.apartment
    to: arming
  - platform: state
    entity_id:
      - binary_sensor.turkontakt_wohnungstur_contact
    to: "on"
condition:
  - condition: or
    conditions:
      - condition: state
        entity_id: binary_sensor.window_contact_bedroom_contact
        state: "on"
      - condition: state
        entity_id: binary_sensor.fensterkontakt_wohnzimmer_contact
        state: "on"
action:
  - service: script.message_uber_alexa
    data:
      message: >-
        Not all doors and windows are closed. Take care of this before you
        leave.
      target:
        - media_player.saschas_echo_dot_kuche
        - media_player.saschas_echo_dot_living_room
        - media_player.saschas_fire
        - media_player.saschas_echo_show
mode: single

The automation for Home Assistant monitors whether your windows and doors are closed before the alarm system is armed or when the front door is opened. Here is a detailed explanation of the individual components:

• Alias"Monitor - windows/doors still open" is used as a designation for this automation so that it can be easily identified.
• TriggerThese are the events that trigger the check.
  • The first trigger monitors the state of the alarm_control_panel.apartment-entity. If this is set to "arming", the automation is triggered.
  • The second trigger monitors the status of the door contact binary_sensor.turkontakt_wohnungstur_contact. If this is set to "on", i.e. the door is opened, the automation is also triggered.
• ConditionThese are the conditions that must be met for the actions to be executed.
  • In this case, there is an "or" condition which states that at least one of the following conditions must be met:
    • The status of the window contact in the bedroom (binary_sensor.window_contact_bedroom_contact) is "on", which means that the window is open.
    • The status of the window contact in the living room (binary_sensor.window_contact_living_room_contact) is "on", which also means that the window is open.
• Action: These are the actions that are executed if the trigger conditions are met and no conditions speak against it.
  • Here is a script script.message_uber_alexa which issues a message via Alexa devices. The message reads: "Not all doors and windows are closed. Take care of this before you leave."
  • The message is sent to several target devices: Sascha's Echo Dot in the kitchen, in the living room, the Fire tablet and the Echo Show.
• FashionThe "single" mode means that the automation is only executed once at a time. Even if further trigger conditions are met during execution, the automation is not restarted until the current execution has been completed.

In summary, this automation ensures that all windows and doors are closed before leaving the house or arming the security system. It warns the user via Alexa devices if this is not the case.

The advantages are obvious

With this device, you can leave your house or apartment with a clear conscience. The days of wondering if you've left a window open are over. In addition to security, this system also offers benefits for the energy efficiency of your home, as no heat is lost unnecessarily through open windows.

In addition to increased security and energy efficiency, this solution also brings a significant increase in convenience to your everyday life. Imagine being able to check from anywhere that all windows are closed and even receive alerts if they are not. This means not only one less thing to worry about when you leave the house, but also optimized control over the indoor climate in your home.

Particularly in the transitional periods, when the weather can change quickly, the automatic monitoring and control of the windows ensures that your heating or cooling costs do not skyrocket unnecessarily. In addition, the system promotes the well-being and health of residents by helping to maintain an optimal indoor climate. The intelligent control system not only contributes to cost savings, but also to a more pleasant and healthier living environment.

YouTube video implementation

Conclusion

The integration of Home Assistant and sensors into your smart home not only offers convenience, but also security and energy efficiency. Automating open window checks is just one example of the countless possibilities offered by Home Assistant. Start making your home smarter and safer today!

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