NS Scout
A pocket sensor that lets Network Survey on iPhone hear the Wi-Fi and Bluetooth around you.
iPhones do not let apps scan for Wi-Fi networks, and they hide the real addresses of Bluetooth devices. So the Scout does the listening and streams what it hears to the app over Bluetooth. Network Survey adds your location and handles the rest: logging, export, streaming and upload to NS Analytics.
How the Scout Works
An inexpensive ESP32 board running open source firmware becomes the ears of your iPhone
Hears What iPhone Can't
The Scout picks up Wi-Fi access points, nearby Wi-Fi devices and the networks they look for, plus Bluetooth LE devices. It sends compact summaries to Network Survey.
Listen Only
It never transmits Wi-Fi frames. Capture is receive-only and Bluetooth scanning is passive.
Updates Over Bluetooth
Install the Scout software once from a computer. After that, Network Survey on your phone keeps it up to date.
What You Need
A supported ESP32 board with 8 MB of flash (4 MB for the C3), a USB cable, and a computer for the one-time install
Espressif ESP32-C5-DevKitC-1
2.4 and 5 GHz. Tested on hardware. The ESP32-C5 is the only supported chip that hears 5 GHz, where most modern access points do their work. Get the N8R8 version, with 8 MB of flash.
Other supported boards
These run the same firmware, but their pin settings come from vendor documentation and have not been verified on hardware yet.
| Board | Bands | Status |
|---|---|---|
| Seeed Studio XIAO ESP32-C5 Tiny, with a LiPo battery charger and an external antenna. Keep the antenna attached: it carries the phone link too.
Where to buy (Seeed Studio)
| 2.4 and 5 GHz | Not yet verified |
| Espressif ESP32-C6-DevKitC-1 | 2.4 GHz only | Not yet verified |
| Espressif ESP32-S3-DevKitC-1 On v1.1 boards (the current version), the status LED stays dark with the prebuilt image, so you won't see the pairing blink. The app still finds the Scout. | 2.4 GHz only | Not yet verified |
| Espressif ESP32-C3-DevKitM-1 | 2.4 GHz only | Not yet verified |
A USB data cable
For the one-time install and for power. It must carry data, not just charge.
A USB power bank (optional)
Keeps the Scout running in your pocket, backpack or car while you survey.
Install the Scout Software
You only do this once. Later updates come from Network Survey on your phone.
- 1
Use a computer with Chrome or Edge
The installer runs in the browser and talks to the board over USB. Safari and Firefox cannot do this.
- 2
Plug in the board
Connect the board to the computer with a USB data cable. Some cables only carry power, so try another if nothing shows up.
- 3
Connect to the board
Open the web installer and click Connect board. Pick the board from the list your browser shows, with a name like USB JTAG/serial debug unit, CP2102N USB to UART Bridge Controller or USB Single Serial, and press Connect.
Open the web installer - 4
Install NS Scout
The installer reads the chip and asks which board it is. Choose yours and click Install NS Scout. It takes about a minute.
- 5
Note its name
When the install finishes, the installer shows the Scout's name, like NS-1A2B. Write it on the board so you can tell your Scouts apart. If no name appears, press the board's reset button and click Read the name again.
Installing erases the board. It forgets any phones it was paired with. If your iPhone was paired with this board before, iOS still has the old pairing and the connection fails until you remove it. Network Survey notices this and shows Pair this Scout again: tap Show me how to forget the Scout in the Settings app under Bluetooth, and the app reconnects it. On Android, the Scout page reads Pairing lost: forget the Scout in Android's Bluetooth settings, then tap Pair again.
Prefer the command line? Each GitHub release has a full flash image per board that you can write with esptool.
Pair It With Your iPhone
Four taps and your Scout is streaming to Network Survey
Power it up
Plug the Scout into a USB port or a power bank. When the LED blinks cyan quickly (yellow on the XIAO), it is ready to pair.
Open Network Survey
On your iPhone, open Network Survey and tap Scouts on the Survey screen.
Tap Connect
Your Scout appears under Nearby with a short name like NS-1A2B. Tap Connect next to it.
Tap Pair
When iOS asks to pair, tap Pair. The LED turns solid blue (solid yellow on the XIAO) once pairing finishes.
On Android, open Network Survey, go to More > Hardware > NS Scout and tap Add a Scout. The Android manual covers pairing and surveying with a Scout.
Reading the Scout
The status LED tells you what the Scout is doing, and the BOOT button handles pairing
| LED | Meaning |
|---|---|
| Short blue blink every 2 s | Idle, waiting for a phone |
| Solid blue | Phone connected |
| Green, 1 Hz | Surveying |
| Cyan, fast blink | Ready to pair: no phone paired yet, or the pairing window is open |
| Magenta, 2.5 Hz | Installing a firmware update |
| Red double blink | Error |
| White, rapid flash for 2 s | All pairings deleted |
Boards with a single-color LED, like the yellow one on the XIAO ESP32-C5, use the same blink patterns.
| Press | Action |
|---|---|
| Hold about 3 s Opens a 60 second pairing window so a new phone can pair. The new phone replaces the old one. | |
| Press within 5 s of power-up and hold about 10 s Deletes all pairings. A phone that was paired with it must forget it too: on an iPhone, tap Show me how on the Scout's page in Network Survey; on Android, forget it in Android's Bluetooth settings. |
Holding BOOT while the board powers up starts the chip's download mode instead of the Scout software, so press it just after power-up. On the XIAO, the BOOT button is labeled B.
Frequently Asked Questions
Does the Scout transmit Wi-Fi?
No. The Scout only listens. It never sends Wi-Fi frames: no probe requests, no active scans, no joining networks and no deauthentication. Bluetooth scanning is passive too. All it transmits is Bluetooth: an advertisement so a phone can find it when its paired phone is not connected (or while a pairing window is open), and its link to your phone. The firmware is open source, and a check in its CI fails any change that calls the chip's Wi-Fi transmit, active scan or connect functions.
Does it need a battery?
The DevKit boards have no battery and run from USB power. In the field, a small USB power bank or a car USB port works well. The XIAO ESP32-C5 has a charger for a LiPo battery if you want a self-contained unit.
Can I use it with more than one phone?
One phone at a time. To move a Scout to a new phone, hold its BOOT button for about 3 seconds until the LED blinks fast, then pair from the new phone. That replaces the old pairing.
Can one iPhone use more than one Scout?
Yes, up to four at once. A single Scout hops between channels, so the app splits the channels between your Scouts and each one misses less. You can also give a Scout one job, like 5 GHz only or Bluetooth only.
Does it hear 5 GHz Wi-Fi?
Only boards with the ESP32-C5 chip receive on 5 GHz. The ESP32-C6, ESP32-S3 and ESP32-C3 boards hear 2.4 GHz only.
Does it hear 6 GHz Wi-Fi or Bluetooth Classic?
No. None of the supported chips can tune to 6 GHz, and the Scout hears Bluetooth Low Energy only.
How do I update the Scout software?
You only use the computer once. After that, Network Survey on your iPhone or Android phone installs firmware updates over Bluetooth. The app checks that each release is signed, and the Scout goes back to its old firmware if an update fails to start.
Does it work with Android?
Yes. Network Survey for Android can use a Scout in place of the phone's own Wi-Fi scanning: no Android scan limit, more detail per access point, Wi-Fi clients, and raw frames. Pair it from More > Hardware > NS Scout. Android uses one Scout at a time, keeps recording Bluetooth with the phone's own radio, and never mixes Wi-Fi from the phone and the Scout in one survey.
Network Survey for iOS
The app your Scout pairs with is coming soon to the App Store. Pair your Scout and survey Wi-Fi and Bluetooth from your iPhone.
Open source firmware • Receive only • Apache 2.0 License