Wi-Fi sensing vs mmWave radar for the home
2026-10-11 · 1 min read
For presence detection, the two camera-free options are Wi-Fi sensing (CSI) and mmWave radar (capability boundaries: CSI sensing survey [1]; the Wi-Fi column reflects our reproducible capture [2]). Both avoid cameras, but their limits are very different.
| Wi-Fi CSI | mmWave radar | |
|---|---|---|
| Hardware | a CSI-capable router/NIC | a radar module per room |
| Coverage | whole home | one module ≈ one room |
| Resolution | coarse (presence/motion/respiration) | fine (micro-motion, position) |
| Still person | relies on breathing micro-motion | more robust |
| Obstacles | multipath-sensitive, metal blocks it | very sensitive to occlusion |
| Privacy | no images, but behaviour can be inferred | no images |
| Cost | ≈0 if you own the router | one module per room |
| Tuning effort | high (environment-dependent) | low (module outputs events) |
Practical recommendation
- Whole-home "is anyone home" → Wi-Fi CSI is the cheapest option, but calibrate on your own data;
- Precise respiration / micro-motion / multi-person positioning → mmWave;
- Hybrid: mmWave for critical rooms, CSI as the whole-home safety net.
When not to use Wi-Fi CSI
Long-still scenarios without breathing variation, metal/water-heavy rooms, or use cases that need accurate people counting and positions (that requires multi-AP fusion).
Related: Wi-Fi CSI explained · Get CSI from a router · Dataset.
References and data sources
Every external claim carries a source and an evidence grade (grading scheme). Grade E marks first-party, reproducible measurements from this project.
- Grade A · standard/review
WiFi Sensing with Channel State Information: A Survey
W. Ma, W. Zhou, X. Wang · ACM Computing Surveys · 2019
doi:10.1145/3310194 · citations 857 · verified: CrossRef API, 2026-10-11 · The field's most-cited CSI sensing survey (857 citations, verified via CrossRef). - Grade E · first-party measurement
This project's 10-minute raw capture (57,293 records / 600.0 s, SHA-256 00373f83…95e2)
Router CSI Lab · 2026
csi.okwujun.pw/zh/datasets/ · verified: Reassembled chunks verified byte-identical (2026-10-11)
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