ESPectre
The future of Wi-Fi sensing
IEEE 802.11bf adds sensing to the Wi-Fi standard. Today ESPectre works with the CSI that ESP32 chips already expose. This page explains what the standard changes, what it leaves open, and where it would fit in ESPectre.
Sections
What IEEE 802.11bf changes
Today, CSI is a by-product of communication. The ESP32 measures the channel only when a packet arrives, so ESPectre has to create traffic with ping, DNS, or raw Wi-Fi frames. Each chip family also reports CSI in its own layout, and nothing tells the access point that a sensor is listening.
IEEE 802.11bf-2025, published in September 2025, adds sensing procedures to Wi-Fi in the license-free bands between 1 and 7.125 GHz, and above 45 GHz. According to the IEEE 802.11 WLAN Sensing Task Group, devices can:
- Announce what sensing they support.
- Ask for and set up the transmissions used for sensing measurements.
- Share the measurement results with each other.
What it does not define
The standard covers how devices take and share measurements, not what the measurements mean. It defines no motion detector, presence detector, or activity classifier. That part still needs signal processing, machine learning, and testing.
It also does not make every new Wi-Fi chip a sensor or give all chips the same API. Devices will still differ in antennas, bandwidth, timing, and data format, so today's detectors will need retesting on the new measurements.
Where it would fit in ESPectre
In ESPectre, CSI capture is separate from what uses it. The ESP-IDF code in the runtime collects measurements; the portable core filters them and runs the detectors; the frontends turn the result into Home Assistant, Matter, or MQTT messages. An 802.11bf source would replace the capture step and keep the rest where the new data allows it.
| Layer | Today | With 802.11bf |
|---|---|---|
| Measurements | CSI from ordinary traffic, through the ESP-IDF CSI API | Measurements requested through the standard's sensing procedures, from a chip and driver that expose them |
| Detectors | Lightweight and High Accuracy, tested on ESP32 recordings | The same approach, retested on new datasets and adapted where needed |
| Messages and integrations | One message model over MQTT and Direct HTTP, plus Home Assistant and Matter | Unchanged where the new measurements allow it |
What has to happen first
Affordable chips must support it
The standard is published, but small, low-cost chips that implement it are not available yet.
Drivers must document the measurements
An open project needs documented access to the measurements, their timing, and their errors, not a feature hidden in closed firmware.
Detectors must be retested
Coordinated measurements may be more consistent, but that has to be shown on real recordings before any detector is trusted on them.
Products must be open about sensing
Sensing uses no images or audio, but movement data can still reveal daily habits. People need to know when sensing is on and how the data is protected.
This work is planned for ESPectre v5, which starts when suitable hardware is available.