Long Range WiFi Scanner Using ESP8266




Introduction: Long Range WiFi Scanner Using ESP8266

About: I like making something useful. And making stuff better.

In this Instructable I make a battery powered portable long range 2.5 band WiFi scanning device used to determine which channel is best for my home network. It can also be used to find open WiFi access points on the go. Cost to make: About $25 dollars I reused some stuff.

EDIT: After assembling this device I've found many different uses for it. Wi-Fi repeater, AP, router with a Ethernet to USB adaptor, range extender for a drone. I cant believe what this little chip can do. and now its mobile!

This 2.5 WiFi band network tool is made with an ESP8266 Node MCU. I am not showing you how to program the ESP, there is enough information out there for that. I will link where to find the stuff I used (both hardware and software).

I used the nodemcu because I can flash what ever software that may be useful in a given situation.

Step 1: Parts List.

1-ESP8266 NodeMCU. $8.39
HiLetgo New Version ESP8266 NodeMCU LUA CP2102 ESP-12E Internet WIFI Development Board Open source Serial Wireless Module Works Great with Arduino IDE/Micropython https://www.amazon.com/dp/B010O1G1ES?ref=yo_pop_ma_swf

1- Small battery bank. $ let’s say 10 bucks I had an old one. I linked similar battery. Make sure it has usb pasthrough so you can use the ESP and charge the battery at the same time.


2- WiFi antennas from old network card. $YAY free!
If you insist on buying a par...$9 bucks
Highfine 2 x 6dBi 2.4GHz 5GHz Dual Band WiFi RP-SMA Antenna + 2 x 35cm U.fl / IPEX Cable for Wireless Routers Mini PCIe Cards Network Extension Bulkhead Pigtail PCI WiFi WAN Repeater https://www.amazon.com/dp/B01GMBUS8O/ref=cm_sw_r_cp_api_hh9RAbH62CEJS

2- Small pieces of wire. $ come on... look around.

1- Roll of super cool carbon fiber tape stuff. $ 5 auto parts store or amazon.
3D Carbon Fiber Film Twill Weave Vinyl Sheet Roll Wrap (12" X 60", Black) https://www.amazon.com/dp/B00O36U76E/ref=cm_sw_r_cp_api_nj9RAbE09H9GM

1- Roll of double sided tape. $ are you even trying to use stuff at your home??

Hot glue, wire cutters, metal file, soldering iron, a knife I think... yeah that’s sounds about right. Next step!

Step 2: Program Your ESP8266 to Do What You Want.

I am not a programmer! However I’ve been experimenting with the ESP. I used Arduino to upload the program. I have tried several different sketches other people have made and I choose this software because it does everything I wish to accomplish. Shows access points, hidden networks, channel numbers, WiFi devices, signal strength, and a great easy to use website interface. So the ESP doesn’t have to be connected to a computer to work.

Full credit goes to its developer!! He did a great job and all the work.


Disclaimer it is illegal to deauthenticate other peoples networks or to use this on public Wi-Fi! Don’t do it!

I don’t intend to use it as a deauthorization tool. With that said I have messed with the children while they were watching YouTube.

Step 3: Prep the Parts

I wrapped the battery bank with that sweet looking carbon fiber because it looked rough. Filed off the pans on the ESP so I can lay flat. And buy out the back of the Wi-Fi antennas so they can pin it and lay flat against the battery bank. Battery bank easily lasts a day with continuous use with power to spare. Also you can still use it as a battery bank.
I had to file back part of the antenna plastic so they would fold up and down without binding on battery bank. I also removed the screw caps to make it easy to attach the wires and sealed them up with some heat shrink tubing.

Step 4: Reason I Added the Antenna.

I didn’t want to spend all day walking around my house scanning to see what my neighbors have their Wi-Fi routers channel set to. As you can see I get significantly more access points after the antennas are added. Increasing the range also makes it easier to find open Wi-Fi networks on the go.

Step 5: Put It Together

So here is what it looks like assembled. I used double-sided tape to hold the ESP chip in place. Hot glue to hold the antennas. I soldered the wire antenna wires to each side of the existing PCB Wi-Fi antenna to hopefully get the best results. Your results may very.

Step 6: Looks Good and Works Great for As Compact As It Is.

Now you can use this to determine what channel is best for your 2.5 wireless access point to prevent overlap and congestion. You can also see hidden networks such as Chromecast and printers. If you perform a station scan you can see how many devices are on a given channel. To give you an idea how compact it is here are some additional photos. Small enough to fit in your pocket. Portable so you can help out a friend or elderly family member. Or free open WiFi hotspots.

Let me know if you liked this or drop me a comment. Thanks for checking this project out.

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    Question 1 year ago on Introduction

    I'm not tec David but I'm in need of tec advice.. How to find a hidden WiFi hotspot in the house. Today everything can be run from programs right from the phone. In the same sense evil can be committed in the house by perverted people. A WiFi hotspot has been interfering with the house WiFi. And it has been seen and made obvious that someone is getting into the house. Please help


    3 years ago

    I'm sorry to inform you that your antenna design is totally wrong. Take a look at this instructable https://www.instructables.com/id/Enhanced-NRF24L01/
    NRF24L01 uses the same freq, so antenna should be similar. You can connect yours antenna's shielding to GND and core to HF signal. You have to cut tracks on PCB to do so. ESP has only one antenna transmitter/reciever, thus using two antennas will only make signal transmission worse.

    The Rubber Duck
    The Rubber Duck

    Reply 3 years ago

    Maybe so. During my testing it works! So although it may not be the best it could be, it did actually increase the number of access points found. If I repurpose it for anything else it may be beneficial to change the Antenna layout but for now it stays.