WiFi

Of course you know what WiFi is. This section focuses specifically on WiFi details you may not yet know that can be very important for using WiFi with home automation and WiFi-enabled microcontrollers.

Overview

A wireless network (WiFi) provides the fundamental infrastructure to work with wireless devices. It makes a significant difference whether you set up WiFi for a typical consumer household, or whether you need it for home automation:

• Coverage: with home automation, there may be much higher requirements for seamless coverage: wireless devices may be located in areas different from consumer devices: garden (moisture and temperature sensors or cameras), garage (garage door sensors, cameras, alarm system), utility rooms (heating system, gas and water meter). WiFi needs to cover virtually every area of your home property.
• Number of devices: Once you start adding smart wireless devices to your home, you quickly and significantly increase the number of devices that are connected to WiFi: every WiFi device (every sensor, smart plug, remote button, etc.) counts as one. Thus, your WiFi needs to be capable of handling this many devices.
• WiFi Bands: Modern WiFi stations use 2.4GHz, 5GHz, and even 6GHz in parallel to transmit data. Each frequency band increases the bandwidth (speed of data transfer) and has individual transmission characteristics that in combination ensures good coverage across walls or levels - but only for consumer devices such as smartphones. Home automation uses WiFi-enabled microcontrollers that exclusively work with the 2.4GHz band. So if WiFi coverage in this particular band is poor, impaired by interference, or if this band was disabled altogether, it hits home automation severely while at the same time, WiFi seems to operate smoothly for consumer devices.

You might want to also look into using Zigbee devices (and add an appropriate Zigbee gateway device to your WiFi network) to shift load off your WiFi and reduce the number of devices that need to connect to your WiFi: Zigbee automatically creates its own network in which any Zigbee device can act as repeater and extend network coverage automatically.

WiFi Stations

WiFi networks are created by one or more WiFi stations that wireless devices can connect to, and in a consumer household, you are typically just concerned about setting a WiFi SSID (WiFi name) and a secret password to access the network - and off you go.

With home automation, additional thoughts and configurations are required to set up and configure a reliable WiFi.

Typical Consumer Setup

In most consumer homes, connection to the Internet is established by a Router that was installed (or provided) by the internet service provider (ISP).

This router is connected to the phone line (or whatever cable the ISP is using), and on its other end it provides ethernet plugs (to connect wired devices) and sets up a simple WiFi Access Point (to connect wireless devices).

Improving Coverage

Simple ISP routers often do not provide sufficient coverage, even for pure consumer scenarios with no home automation ambition at all.

That’s why WiFi coverage often is improved by using these strategies:

• WiFi Extenders: devices that pick up the WiFi signal from one station and amplify and re-send it. The involved data hopping from one device to the next slows down data transfer and may work only for one of the WiFi bands.
• Additional Access Points: by setting up additional WiFi access points in different locations of your home, wireless devices can connect to any of them, effectively extending coverage. Each Access Point needs to be connected to the wired network, though.
• Mesh Networks: Only the main WiFi station needs to be connected to the wired network. The satellite stations use wireless or wired backhaul connections to connect with each other.

Home Automation Aspects

Mesh WiFi is the most flexible strategy for setting up a WiFi network suitable for serious home automation: a mesh allows for extending coverage to any rooms, levels or locations simply by adding another satellite.

Each new WiFi station also increases the total number of devices that can connect to WiFi. This number depends on two factors:

• WiFi Station Capability: each WiFi station has its own maximum number of clients it can serve. Simple devices typically allow for 20-30 clients, low-budget devices support up to 50 devices, main-stream devices can serve 100 devices, and high-end stations support 200 or more devices. This number is per station. In a mesh, you can granularly control the number of devices by adding another satellite to areas with many devices, or by switching the satellite type to a model with more capability.
• Bandwidth: the data that can be transferred by WiFi is another limiting factor that typically is not relevant in home automation: sensors, plugs, and even cameras transmit only a fraction of the data that your smartphone or a TV set utilizes.

When setting up a mesh WiFi, here are a few considerations:

• Disable Original AP: disable the built-in WiFi access point in your ISP router as it is no longer needed and would just interfere, especially if your new WiFi is using the same SSID (network name).
• Use Wired Backhaul: whenever possible, use an ethernet cable to connect satellites with the main station. A wired backhaul is much faster and more stable. If no cable connection is possible between given satellites, they use a wireless backhaul automatically.
• WiFi Band: make sure your WiFi uses the 2.4GHz band which is the one used by wireless-enabled microcontrollers and devices.

WiFi Mode

Each WiFi network operates in one of two modes which can have significant impact on whether your home automation solution work well or not:

• Router Mode: the main WiFi station acts like a Router: it defines its own subnet, runs its own DHCP server, and issues its own IP addresses to connected devices.
• Access Point Mode: each WiFi station (regardless whether main station or satellite) connects wireless devices to the original router. Devices receive their IP addresses from the original router, and no subnet is created.

Impact Of Subnets

Most WiFi stations use Router mode by default, so if you have already set up your WiFi and not paid special attention to the WiFi mode, chances are you are currently using Router mode.

While you can change the WiFi mode easily at any time, do not do it just yet! Understand the consequences first (see below).

mDNS Cannot Traverse Subnets

In Router mode, your WiFi network is a separate subnet. mDNS name resolution does not work across subnets. That has significant consequences when mDNS device names are used to resolve the IP address of a device.

Here are typical real-world consequences that a home automation user may experience:

• Home Assistant: wireless devices are not discovered and need to be manually added via their IP address.
• ESPHome: wireless devices are reported to be offline when in fact they are online.

These issues occur because the user has connected his Home Assistant server with a network cable to his wired network, whereas the devices connect wirelessly to WiFi, and his WiFi runs in Router mode.

Because of the WiFi Router Mode, neither the devices can contact the mDNS name homeassistant.local (because it exists in a different subnet), nor can Home Assistant (as well as its ESPHome add-on) contact the mDNS device name of a wireless device to determine its online status (because it exists in a different subnet).

Is My Network Setup Currently Affected By This?

To check whether your current network setup is problematic, determine the local IP addresses of a wired and of a wireless device, and compare them.

First start by finding out the local IP address assigned to a wireless device such as your smartphone. The process of getting to see the local IP address is different for each device type and operating system. Here are the steps for iPhones:

1. Tap Settings, then tap WLAN or WiFi (the setting that you use to connect to a WiFi).

2. In the top area, you see a checkmark and the name of the WiFi you are currently connected to. At the right end of this line, there is a round info symbol. Tap it.

3. You now see the WiFi details. Scroll down until you see IP Address. Make a note of the currently assigned local IP address.

Next, do the same with a wired device, i.e. your PC (provided it is connected to your network via network cable). Again, the procedure varies with the operating system you use. Here are the steps for Windows 10:

1. Open the start menu, then click the gear symbol to visit Settings.

2. Click the category Network & Internet, then in the sidebar to the left, click Ethernet. Now you see your active ethernet connection(s).

3. Double-click your ethernet connection icon to view its properties. When you scroll down a bit, you see its IPv4 address (do not confuse it with any driver versions that may look similar). Make a note of the address.

As a rough estimate, when you compare the first three numbers of both IP addresses, and they differ, then most likely you are using separate subnets.

Fixing Your Network

As you have seen, the WiFi mode can cause significant issues with home automation:

• Access Point mode: does not create subnets and thus uses the primary Router and its DHCP for all devices, wireless and wired. This is the simplest way to ensure that all devices and computers can contact each other.
• Router mode: do not allow wired devices to discover wireless devices (and vice versa).

Hold on - do not change the WiFi mode of an existing WiFi network just yet! Before you consider to make any changes, first read on to fully understand the consequences.

Caveat: Access Point Mode

Switching a WiFi network to Access Point mode may solve the issues outlined above, but may cause new trouble on other ends:

• DHCP Limitations: once you disable WiFi Router mode, all devices in your home start requesting new IP addresses from your primary router. Since this router often is quite old, it may not at all be capable of issuing this many IP addresses, leaving random devices without valid IP address and inaccessible.
• IP Address Change: if you decide to switch WiFi mode from Router mode to Access Point mode for a network that already ran for a while, this will cause all devices to receive new IP addresses from a completely different range. This can break existing integrations in Home Assistant, may leave behind devices that you assigned static IP addresses manually, breaks pre-existing Cloudflare tunnels you may use for remote access, and much more.

So what now?

Recommended Fixes

Here are some remedies to fix the subnet issues without creating new issues elsewhere.

Using WiFi Router Mode

If your WiFi is currently running in Router mode, then the easiest and least impactful fix is to ensure that your computers connect to your WiFi so they share the same subnet with your devices - at least the one computer that is running Home Server/EspHome or is otherwise supposed to manage your devices:

If you are using a Raspberry Pi to host Home Assistant, connect it wirelessly to your network, or plug its network cable into one of your WiFi stations.

I cannot connect an Ethernet cable to my WiFi station(s)

If your WiFi Stations do not have a spare ethernet plug to connect wired clients, use of of these alternatives:

• WiFi Extender: purchase a cheap WiFi Extender. These devices connect a network cable to a WiFi network.
• Mesh Satellite: check your WiFi box type and vendor. If you are running a Mesh WiFi, you may want to purchase a compatible satellite with network cable connector. This option has the benefit of extending your WiFi coverage.
• Raspberry Pi: If you know the inner workings of Raspberry Pi, you can also reconfigure it so it uses its own built-in WiFi adapter to directly connect to your WiFi. Unplug its network cable in this case.

Using WiFi Access Point Mode

The cleanest solution is to completely redesign your entire network and operate your WiFi in Access Point mode - beware: this is not done in a few minutes, and most definitely not done just by switching WiFi mode to Access Point mode.

Seriously: the most reliable way to waste many days with completely senseless work at a high heart frequency is to switch an existing WiFi network from Router mode to Access Point mode without proper preparation.

Before you switch the WiFi mode to Access Point, consider these aspects:

• Primary Router: is your primary router and its DHCP service capable of handling hundreds of devices? Do you possibly have to edit its settings and define a wider DHCP address range? Do you possibly have to change the network subnet mask from 255.255.255.0 to 255.255.252.0 to extend the number of available IP addresses from 253 to 1022? Or do you even have to switch to an external DHCP service?
• Static IP Addresses: have you set up any static IP addresses manually? Will they still work with the new DHCP settings?
• Integrations & Tunnels: Have you set up any integrations or configured any add-ons in Home Assistant that rely on IP Ranges? Will they continue to work with your new DHCP settings? Or have you set up a Cloudflare tunnel to access your home network remotely, and does the tunnel possibly require re-configuration when you change the IP Range of your home network?

If your computer must stay in the wired network, you may be able to work around the subnet issue by re-configuring software like Home Assistant and ESPHome to use IP addresses and ping instead of mDNS. Or, you can add a simple manual network switch that can switch between wired and wireless networks. Or, you can add another network card to your computer and connect it to both subnets. There are many more workarounds. Just make sure you understand the problem and configure your network in such a way that all devices can contact each other and share the required information.

Slow Website?

This website is typically very fast, and pages should appear instantly. If this site is very slow for you, then your routing may be messed up, and this issue does not only affect done.land, but potentially a few other websites and downloads as well. Here are simple steps to speed up your Internet experience and fix issues with slow websites and downloads..

Comments

Please do leave comments below. I am using utteran.ce, an open-source and ad-free light-weight commenting system.

Here is how your comments are stored

Whenever you leave a comment, a new github issue is created on your behalf.

• All comments become trackable issues in the Github Issues section, and I (and you) can follow up on them.

• There is no third-party provider, no disrupting ads, and everything remains transparent inside github.

Github Users Yes, Spammers No

To keep spammers out and comments attributable, all you do is log in using your (free) github account and grant utteranc.es the permission to submit issues on your behalf.

If you don’t have a github account yet, go get yourself one - it’s free and simple.

If for any reason you do not feel comfortable with letting the commenting system submit issues for you, then visit Github Issues directly, i.e. by clicking the red button Submit Issue at the bottom of each page, and submit your issue manually. You control everything.

Discussions

For chit-chat and quick questions, feel free to visit and participate in Discussions. They work much like classic forums or bulletin boards. Just keep in mind: your valued input isn’t equally well trackable there.

  Show on Github    Submit Issue

^{_{(content created Jul 17, 2024)}}