N E T L E N S
Wi‑Fi made visible.
A handheld signal‑survey instrument for Android. Walk a space - an apartment, an office, a warehouse - and watch a real‑time heatmap form beneath your steps.
Fig. 00Status
Get the closed beta.
Closed testing is the pre-release build on Google Play - install it early and help shape the final release.
Fig. 01How it works
NetLens exists because every other Wi‑Fi heatmap app on the Play Store came up short for real field surveys. Some demanded floor plans. Some demanded accounts. Most produced maps that didn't line up with what the walls were actually doing. This is the tool that should have already existed.
Hold the phone in front of you and walk. The rear camera supplies visual‑inertial tracking - the same simultaneous‑localization machinery that powers ARCore - so every Wi‑Fi scan is anchored in 3D space by the phone's own motion. No floor plan to upload, no setup, no markers on the walls. Location services, if left on, add a coarse fix so a scan remembers which building it came from; left off, the rest still works.
The map fills in along the path you walk. Cells are interpolated from the samples your radio recorded, bounded to the corridor you covered - areas you didn't walk stay empty. Ready to export as a PDF report or share as a PNG.
Fig. 02Screens
Camera view above a top‑down minimap. ARCore tracks your camera through the space in 3D, so every reading lands accurately on the map as the heatmap grows beneath you.
A completed scan rendered with the viridis colormap. Cell colors come from real Wi‑Fi samples taken along the path you walked.
Isolate one access point. See exactly how far its reach extends.
Real‑time dBm for several APs at once, each a colored line on a rolling chart, so you can walk a hallway and watch the signals climb.
Photograph the AP as you scan. Each photo gets pinned to the map with the exact RF context at that location.
Polished reports for clients, screenshots for friends, raw data for nerds.
Fig. 03Specifications
- Platform
- Android 13+ · ARCore 2.4 / 5 / 6 GHz
- Bands
- 2.4 GHz · 5 GHz · 6 GHz (where the radio supports it)
- Tracking
- Visual‑inertial odometry via ARCore for in‑room positioning. No external markers. No floor‑plan upload.
- Location
- Android requires the Location permission for any Wi‑Fi scanning. NetLens also stamps a coarse GPS fix on each scan to remember which building it was from - stored locally, never transmitted.
- Storage
- 100% on‑device. Scans live in the app's private sandbox. Uninstall removes everything.
- Network
- No accounts. No scan data ever uploaded. Free tier serves AdMob banners (advertising ID + IP only); Pro removes them, leaving only opt-in crash reports and an anonymous diagnostic check-in.
- Exports
- PDF report · PNG image · CSV raw samples
- Measurement
- Cell colors are interpolated (inverse‑distance weighting) from Wi‑Fi samples your radio actually recorded - bounded to the corridor you walked. Areas not walked stay empty rather than being extrapolated to look plausible.
Fig. 04Pricing
Free
$ 0
NO ACCOUNT REQUIRED
- Every feature, unlimited use
- PDF, PNG, and CSV exports
- Banner ad in the analyze view
- Discreet watermark on PDF and PNG exports
Ad-free - one‑time
Coffee
ONE PURCHASE, FOREVER
- Everything in Free, identical
- No ads, anywhere
- No watermark on exports
- Restores across devices on the same Google account
Why is capture free? Because a Wi‑Fi survey tool you can't actually use is useless. The free version is the complete app - every feature, unlimited captures, every export format. The paid version is the same app with the banner ad and the export watermark removed. No locked features either way.
Fig. 05Questions
Do I need a floor plan to make a Wi-Fi heatmap?
No. The rear camera supplies visual‑inertial tracking - the same motion tracking that powers ARCore - so every Wi‑Fi reading is anchored in 3D by the phone's own movement. There is no floor plan to upload and no markers to place. A floor plan, sketch, or screenshot can optionally be placed underneath the finished heatmap to line it up to real rooms.
How do I run a scan?
Hold the phone in front of you and walk the space. A live heatmap fills in along the path you walk, graded from weak to excellent signal.
What kinds of spaces can NetLens scan?
All of them, from a small home to a large office or warehouse, and even outdoors. The visual‑inertial tracking holds position as you walk, so the same workflow covers a single room or an entire building.
Can I scan multiple floors?
Yes, but each floor would ideally be scanned separately to avoid distorting the readings. Scans can be organized into a project, and each floor can be scanned individually. The PDF export can create a report for a single scan, or for the entire project.
What do the heatmap colors and dBm ranges mean?
Coverage is graded Excellent at −55 dBm and stronger, Good from −65 to −55, Fair from −72 to −65, Poor from −82 to −72, and Dead below −82 dBm. The continuous heatmap surface spans roughly −85 dBm (weak) to −40 dBm (strong).
How is the space between the path I walked filled in?
Cells are interpolated with inverse‑distance weighting from the actual samples the radio recorded, bounded to the corridor you physically walked. Unwalked areas are left empty instead of being extrapolated to look plausible.
How accurate is the positioning?
Each scan report includes a real position‑accuracy estimate, and a scan whose tracking drifted is flagged with how far off it may be rather than presented as clean. In testing, a laser‑measured hallway read back to within a tenth of a foot on two different phones.
Does it cover 6 GHz and Wi-Fi 6E?
Yes. The map and the live tools can be filtered to the 2.4, 5, or 6 GHz band. As with any survey app, the 6 GHz band appears only when the phone's radio supports and reports it.
Does NetLens need an account or an internet connection?
No to both. You do not need to be online to run a scan - capturing the heatmap, viewing it, and exporting all work fully offline, with no account and no data connection. (Wi‑Fi itself must be switched on, since the scan reads the networks around you, but the phone never connects to them or uses the internet.) The only network use is the free‑tier banner ad, which Pro removes, plus optional opt‑in crash reports - neither is needed to scan.
Is my scan data uploaded anywhere?
No. Wi‑Fi readings, motion data, photos, and notes are stored only in the app's private storage on the device and are never transmitted. There is no cloud sync; data leaves the phone only when you tap Export and choose where the file goes.
Why does a Wi-Fi app need Location permission?
Android only returns Wi‑Fi scan results to an app that holds location permission, even when no location is being recorded. NetLens uses those results to read signal strength and frequency, not to track you, and the survey still works with location services switched off.
Which phones are supported?
Any Android phone running Android 13 or newer with ARCore (Google Play Services for AR) support and a working rear camera.
Is it free, and what does Pro cost?
Capture is free with every feature, unlimited scans, and PDF, PNG, and CSV export. The free tier shows a banner ad in the analyze view and a small watermark on PDF and PNG exports; a one‑time purchase, about the price of a coffee, removes both. No features are locked on either tier.
What happens if I scan in low light or move too fast?
The camera needs light and detail to track, so a quiet on‑screen coach appears before the map can drift, escalating to a buzz if conditions stay poor. Moving or turning too fast triggers a motion warning. If a scan is disrupted anyway, the good portion can be kept (with the drifted tail trimmed) or the scan retried.