Even though Macs don’t support Wi-Fi 6E, WiFi Explorer Pro 3 and Airtool 2 offer visibility into the 6 GHz band when using remote sensors that can scan or capture traffic on 6 GHz. One of these remote sensors is the WLAN Pi.
This blog post will show you how to build a WLAN Pi R4 with support for scanning and capturing Wi-Fi traffic on the 6 GHz band using WiFi Explorer Pro 3 and Airtool 2. A WLAN Pi R4 uses a Raspberry Pi 4 as the platform (hence the R4 name). With the right parts and thanks to the work of the WLAN Pi team, we can have a fully functional remote sensor with Wi-Fi 6E support without the need for additional tweaks or modifications.
To build a WLAN Pi R4, you will need a Raspberry Pi 4, a micro SD card, and an external USB Wi-Fi adapter. These three components are sufficient for a working remote sensor in a headless configuration. Still, with a few more parts, you can quickly build a complete WLAN Pi R4. You will also need a display module with buttons, an aluminum case, and the 3D-printed WLAN Pi fascia kit.
Let’s talk in detail about the parts you will need to build the WLAN Pi R4 and where to find them:
Raspberry Pi 4
The Raspberry Pi 4 is the main component you will need to build a WLAN Pi R4 and the hardest to find nowadays, unfortunately. Many are lucky enough to have one or more Raspberry Pi 4s lying around, but if you don’t, we suggest using www.rpilocator.com to track the availability of Raspberry Pis worldwide. We recommend getting a Raspberry Pi 4 Model B with at least 2 GB of RAM.
Where to find it? Visit www.rpilocator.com to see which stores have Raspberry Pi 4s in stock, or follow them on Twitter for real-time updates when Raspberry Pis become available.
Update (09/27/2023): Raspberry Pis are becoming available again as supply recovers to pre-pandemic levels. You may now find some units on Amazon.
Micro SD Card
A 16 GB or larger micro SD card should work fine. There are many flavors of micro SD cards. The SanDisk Ultra or Samsung Evo Plus Class 10 micro SD cards are good options.
Where to find them? You can find the SanDisk Ultra 32 GB Micro SD Card and Samsung Evo Plus 32 GB Micro SD Card on Amazon.
External USB Wi-Fi 6E Adapter
The Raspberry Pi 4 comes with built-in Wi-Fi. However, it doesn’t support the 6 GHz band and cannot be reliably used in monitor mode. We will need an external USB Wi-Fi adapter instead: the Comfast CF-951AX or CF-953AX.
These Comfast adapters are sold as 802.11ax dual-band (2.4/5 GHz) Wi-Fi dongles. Nevertheless, their internal MediaTek MT7921U chipset also supports 6 GHz (a custom kernel and driver are needed to make these adapters work on the 6 GHz band, but the WLAN Pi OS image already has everything we need to make it work).
The CF-951AX and CF-953AX are identical, except that the CF-953AX comes with (soldered) external antennas. The CF-951AX works well and has a smaller form factor. On the other hand, the external antennas on the CF-953AX offer a better range.
Where to find them? You can find the CF-951AX on AliExpress and BadgerWiFi. The CF-953AX is available on AliExpress.
Display HAT for Raspberry Pi with Buttons
The display module you will need is the 1.44″ LCD Display HAT for Raspberry Pi from Waveshare. It has three buttons and a joystick that you can use to access many WLAN Pi functions via the Front Panel Menu System (FPMS).
Where to find it? You can purchase the display module on Amazon or directly from Waveshare.
Waveshare Lightweight Aluminum Alloy Case for Raspberry Pi 4
The case and the fascia kit (see below) help put everything together. This aluminum case from Waveshare is very well done and allows the Pi to run cooler without needing a fan.
Where to find it? You can purchase the case directly from Waveshare.
WLAN Pi Fascia Kit
Nick Turner, from the WLAN Pi team, designed the fascia kit specifically for the WLAN Pi R4. The kit has the screws and parts needed to attach the fascia to the aluminum case. It helps to keep the display module and buttons in place and gives the Pi the WLAN Pi look.
Where to find it? You can purchase the fascia kit here.
Once you have all the parts, the WLAN Pi R4 is very easy to assemble. Just follow the instructions that Nick provides in his assembly guide here.
Next, download the latest WLAN Pi OS image and flash it onto the micro SD card, then insert the SD card into the WLAN Pi R4 and connect it to a power source or a USB port on your Mac.
If you choose to power the WLAN Pi R4 with a conventional power supply, you will need to connect it to the network using the Ethernet port. On the other hand, because the Raspberry Pi 4 supports the OTG specification, if you connect the WLAN Pi R4 to a USB port on your Mac, you can access it using the same USB cable via the network connection established between the computer and the WLAN Pi R4. In either case, the WLAN Pi R4 will display the IP address you can use to connect. When using OTG, the IP address of the WLAN Pi is 169.254.42.1.
The first time you boot the WLAN Pi R4, you need to SSH and change the password. The username is wlanpi, and the default password is also wlanpi. You won’t be able to use the sensor with WiFi Explorer Pro 3 or Airtool 2 until you change the default password.
You will also need to set the regulatory domain. You can set the regulatory domain via the FPMS:
You can also set the regulatory domain by connecting to the WLAN Pi R4 via SSH and typing the following commands:
Your WLAN Pi R4 is now ready to be used as a 6E remote sensor. To use the WLAN Pi R4 as a remote sensor with WiFi Explorer Pro 3, see Connect to a remote sensor. To use the WLAN Pi R4 as a remote sensor with Airtool 2, see Capture using a remote sensor.
The WLAN Pi R4 is a good alternative for those who already have a Raspberry Pi 4 and would like to benefit from many of the features that the WLAN Pi has to offer. Together with the Comfast CF-951AX or CF-953AX adapters, it becomes an affordable remote sensor for working with Wi-Fi 6E.
Note: Intuitibits participates in Amazon’s and AliExpress’ affiliate programs. We may receive a small payment when you click a link and make a purchase.
Thanks for the great writeup Adrian.
In the current scenario there a way to do channel rotation on 6 GHz (or all/select) channels while capturing packets . i think wifiexplorer does that right?
B
Hi Bhupinder,
Airtool 2 doesn’t have an option to capture using channel hopping. WiFi Explorer Pro 3 does implement channel hopping because it’s trying to find networks on every channel but that same function is not implemented in Airtool. What would be the use case for capturing on multiple channels?
I feel it would a nice to have feature to capture using rotating channel scan to get an indication of devices in the air.
[…] Previous […]
running this image in laptop is it possible ?? sorry for dumb question
Hi tumpak, it is not possible. The image is only compatible with the Raspberry Pi. However, you can easily configure a Linux laptop as a remote sensor. For more details, see: https://intuitibits.com/help/wifiexplorerpro3/#/topic-en.lproj-connect_remote_sensor