mmWave vs. Wi-Fi Sensing - Community Guides - Home Assistant Community

mmWave vs. Wi-Fi Sensing

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mike2872<br>(Mike)

May 18, 2026, 12:12pm

Hey everyone,

As some of you may know a handful of Wi-Fi Sensing projects have started emerging with Home Assistant support. I'm working on one of them and naturally have a strong interest in the field. The primary option for presence detection has long been mmWave, where Wi-Fi Sensing has primarily been a research area. But this past year multiple projects have arisen where this technology can actually be used in non-lab environments. For my own projects and home setup, I'm using a combination of Wi-Fi Sensing and mmWave, and I thought I would create a comparison between these two technologies, to give you an idea of the strengths and weaknesses of both.

I'm not going to go deep into how each technology works. That is for another post. But the short version is that Wi-Fi Sensing works by analyzing how existing Wi-Fi packets are being affected by humans (we are mostly water and therefore affect the signal a lot) to detect presence. Humans affect mmWave in roughly the same way, but instead of Wi-Fi packets they use a dedicated sensing network, usually at much higher frequencies (10-100GHz). This means that Wi-Fi Sensing can be added to existing Wi-Fi devices as a software-only add-on, where mmWave are dedicated sensors you have to buy separately.

Hardware

mmWave sensors are dedicated hardware. People in this community usually go for LD-2410, LD-2450, Aqara FP2, Everything Presence One etc. Wi-Fi Sensing can be added to existing Wi-Fi devices, but the current projects only support devices where it's possible to extract Channel State Information (CSI), which is the part of the Wi-Fi packets that are analyzed. Currently, the most practical devices to extract CSI from are ESP32s. This is fortunate since ESP32s are extremely cheap, and many people in the HA community already have a lot of these deployed at home (e.g. ESPHome projects). The Wi-Fi Sensing projects today typically work as an external ESPHome component and/or provide flash tools for easy one-click flashing of ESP32s.

Range and coverage

Most mmWave devices for smart homes are typically effective between 6-10 meters. The range of Wi-Fi Sensing is much higher, usually 10-30+ meters and primarily limited by how far the devices can maintain a strong Wi-Fi connection.

Through-wall capabilities

mmWave operates at frequencies that mostly render it unusable when passing through one or more walls, especially thicker ones. Wi-Fi Sensing operates at frequencies that were specifically engineered to propagate through walls and often works through multiple thick walls.

Localization and zoning

In order to do localization you need to be able to determine the direction of the part of the signal being received, which requires multiple phase-coherent antennas. You also need to determine how far the signal travelled, which is limited by the bandwidth of the device.

mmWave devices all have multiple TX/RX antenna pairs with broad bandwidth which allows very precise zoning. This means you are able to create tight zones such as only detecting presence at a desk.

Wi-Fi Sensing is theoretically able to do the same when using devices with multiple antennas with broad bandwidth (e.g. a router with 160MHz bandwidth), but current ESP32s only have single antennas and use 20/40MHz.

In theory this means Wi-Fi Sensing is not able to do localization, although in practice, zoning is done indirectly by creating a mesh of ESP32s and performing some averaging tricks to achieve rough zoning. The new ESP32-E22 (announced, unknown release date) is the first to have two phase-coherent antennas and support 160MHz. That changes things, and we are therefore going to see proper localization implemented in Wi-Fi Sensing projects in the near future.

Right now mmWave has the tightest zoning, but Wi-Fi Sensing still does it fairly well for room-level localization and is going to catch up soon.

Deployment and pricing

The fact that the Wi-Fi Sensing projects today are software-only and use ESP32 means that presence detection can be added to a home for a few bucks, or even added to ESPHome devices already deployed around your house using an external ESPHome component. The fact that these devices are already in your home removes the need for dedicated devices to do presence detection. The through-wall capabilities also mean that devices can be hidden in drawers, closets or even inside walls (e.g. install the ESPHome component on a Shelly relay).

As a conclusion I think Wi-Fi Sensing today has an edge in range, price and ease of deployment, where mmWave has the best zoning capabilities. But in the near future when it's feasible to implement localization on ESP32s (or if other devices come out with easy CSI extraction), I think the edge of mmWave's zoning is going to disappear.

I'm going to list all the projects I know that...