Cheap WiFi Range Extender for IoT




About: We are two brothers who like to make things.

How to build your own WiFi extender from a cheap $2-$8 ESP8266 WiFi module

***EDIT: Since the writing of this instructable, the firmware has been improved greatly, with the additional of a GUI settings page (like a normal router), firewall, power management, indicator LED, and automatic mesh networking (connect multiple units together) features! I will update this instructable at some point, but meanwhile, check out the details at Martin's GitHub page: link***

Notes: It will have slower connection speeds the farther the extender is away from your router, but fast speeds are not necessary for many IoT projects.

I needed a cheap way to increase WiFi range so that a IoT snail mail alert device could reach a distant WiFi router to connect to the internet and send notification to my phone. I stumbled upon Martin Ger's WiFi NAT Router firmware for the ESP8266 WiFi module, flashed it onto my $2 ESP-01 WiFi module, and it works quite well.

The router my extender connects to only reaches about 20 feet due to a wall, but with the extender plugged in 10 feet to 50 feet away from it, the connection reaches 310 feet and is just fast enough to stream YouTube!

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Step 1: Download the Files

Download the .zip file called "" from which contains the firmware files and software tools you will need.

Step 2: Extract (Unzip) the File Folder

Unzip a.k.a. extract the zip you just downloaded to a location on your computer that is easy to find.

On Windows, this is done by right-clicking on the zip, and clicking "extract all".

Step 3: Get the Required Parts

You will need to acquire a few parts. the shopping links are below. You might be able to find cheaper identical parts somewhere else.

ESP8266 ESP01 + USB Adapter Pair - DealExtreme

Step 4: Wait for the Parts to Arrive

Step 5: Download the Driver

In order to get the USB adapter talking to the computer, you may need to install the CH340 driver.

The subfolder from the zip you downloaded and extracted is called "CH341SER_win" for Windows or "CH34x_Install_mac" for Macs.

Simply open the program in the folder and install the drivers.

Step 6: Flash the Extender Firmware Onto the ESP8266

Plug the ESP01 into the USB adapter, plug it all into your computer, and flip the physical switch to "Prog" programming mode not "UART" mode.

Wait a minute for the drivers to initialize, then open up the program in the subfolder called "flash_download_tools_v3.4.1_win".

Open the next subfolder called "_MACOSX" if you are using a Mac, or open the subfolder called "FLASH_DOWNLOAD_TOOLS_V3.4.1_WIN" if you are on a Windows PC.

Run the application called "ESPFlashDownloadTool_v3.4.1" and select "ESP8266" after that.

Setup that program to the setting shown in the screenshot below if you are using the ESP01 from the earlier shopping step:

1. If you are using a NodeMCU or Wemos D1 Mini module instead of the ESP01 or ESP07, switch the part that says "8Mbit" to "32Mbit" instead

2. For the ESP01 or ESP07, under "Download Path Config", click the three dots button for each section and browse to find the "firmware_sdk_1.5.4". Click each one and type out their names to the right as shown in the screenshot e.g. "0x00000" and "0x40000"

2.2. If you are using a different ESP8266 module variant instead of the esp01 I suggested, use the folder named "firmware" and use those .bins instead with their corresponding names to the right.

3. Select the COM port you want, and set the baud rate to "115200", then click "start", "flash" or "connect".

4. When it says "finish", unplug your adapter and ESP8266 module from your computer.

5. Flip the physical switch on the USB Adapter back to non-programming non-flash mode. This is important!

Step 7: Configure Your Extender

You must connect a computer to your extender in order to configure it. You can do this by using a serial terminal app such as the Arduino IDE serial monitor, or a program such as Putty.exe, setting the baud rate to "115200" with NL&CR (new line and carriage return) enabled then physically plugging the extender into your computer, OR you can use a connect wirelessly by connecting your device to the extender's WiFi (default name is "MyAP") and then use a Telnet app such as Putty.exe or JuiceSSH and adding a new connection on the ip address "" with the TCP port set to "7777".

I have used the JuiceSSH app for Android and Arduino IDE Serial Monitor without hiccups

Once you have connected over telnet or serial, type the following bolded commands each followed with hitting the enter key:

(Without quotes, and replacing the hashtag symbols with you desired settings.)

set ssid #### This sets to the name of the router hotspot you want the extender to extend.

set password ##### This sets the password of the router hotspot you want the extender to extend.

set ap_ssid ##### This sets the name of the extender's hotspot.

set ap_password #### This sets the password of the extender's hotspot. NOTE: the password must be more than 8 characters long!

set ap_open 0 This turns password protection ON so only people who know the password can connect to the extender.

save This saves your settings.

quit This terminates a remote session.

So for example:

set ssid homewifi
set password 12345678
set ap_ssid makerextender
set ap_password 1234
set ap_open 0

Unplug the extender. That's it for setup!


You ought to wait a couple seconds between typing in each command, and you might need to type save after each command!

If you need to wipe all your settings back to default, you can type reset factory followed by save

For a master list of all possible commands, you can type help.

To see your configuration, you can type show .

EDIT: If you are using the Instructables mobile app, the bolding of commands in this step might not show as bolded. Let me know if that is the case!

Step 8: Encase Your Extender

You can use an plastic container to house your extender.

I plugged the extender (both the esp01 and the usb adapter) into a USB charger, and stuffed it all into half of a tootbrush travel case, then hot glued a seal to rain proof it.

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41 Discussions


1 year ago

Have you ever run this of a power bank? Is it power hungry or low power long run time? I dont have ac power and would like to run one off a battery bank..

1 reply
Maker SagaBlucmal

Reply 5 months ago

It is power hungry about 250ma peak so it only lasted a few hours on my power bank. Try a solar panel and a battery.


1 year ago

my USB adapter doesn't have the physical switch : ( what should i do now ?!

2 replies
Maker Sagahossein_6969

Reply 5 months ago

I believe you will need to solder a jumper wire between CHIP_EN pin and VCC pin.


Reply 1 year ago

this is the solution
i found it myself and its work well
if you are the on that have a USB serial adapter that doesn't have any switch with this trick you can make it as the one that this article mention
you should know that the thing that you have is just a serial adapter and you cant program your esp with that
to do programing thing you have to this
if you are using a button like this you have to push it before you plug in an hold it tell programing done


1 year ago

works fine on a -201 module. That's the white one with the external IPEX antenna connector. Waiting for a 6dB antanna to extend the operating distance even more!

Has someone tried using ESP32? Is the source code aviable? The ESP32 handels the WLAN tasks with a dedicated processor so it might be possible to handle additional tasks.

Thanks for the great work!

2 replies
Maker Sagajbruening

Reply 5 months ago

I reached out to the developer, Martin Ger, and he stated there is not ESP32 support currently nor are there any plans to port it since the ESP32 is much pricier.


Reply 5 months ago

Can't flash it on esp-201.
flash completes but then nothing.
works fine on esp 01

The TopG

8 months ago

Can I use it many of these extender connected together?


Question 8 months ago

Great project that I've implemented to enhance the wifi network to my external camera. Unfortunately I can ping the camera but I can't receive a picture. What maybe wrong. Any hint is appreciated.


Question 1 year ago

works fine. But cant connect via putty and via browser.

Cheryll DaneC

Question 1 year ago

i have 3 esp 01, one of them, complete succes, and i can open via my browser, but, why my 2 other esp cannot do same thing? but its work well with putty, but i cannot connect to


1 year ago

Hi. JuiceSSH and Connectbot demand a username@
I have tried root, user, MyAp, and none of the usernames work.
Can you help please?


Question 1 year ago on Step 7

Wifi (default name is "MyAP") not show in Nodemcu esp8266 after Flash the Extender Firmware. please help


1 year ago

Hi. Can i use this firmware and then also upload my arduino .ino code onto the esp?. Will it work as a mqtt device and repeater at the same time?


1 year ago

Hie, thanks so much for this. i have used it for a MQTT switch sitting in my sunroom which doesnt get consistent wifi signal. However, do you have any suggestions on how i can have the end device given a static ip address like my current router has given it?

2 replies
Maker SagaUmerF2

Reply 1 year ago

Yes, I think that is possible. For example some commands,

  • set automesh [0|1]: selects, whether the automesh mode is on or off (default), see details here
  • set network ip-addr: sets the IP address of the internal network, network is always /24, router is always x.x.x.1
  • set dns dns-addr: sets a static DNS address that is distributed to clients via DHCP
  • set dns dhcp: configures use of the dynamic DNS address from DHCP, default
  • set ip ip-addr: sets a static IP address for the ESP in the uplink network
  • set ip dhcp: configures dynamic IP address for the ESP in the uplink network, default
  • set netmask netmask: sets a static netmask for the uplink network
  • set gw gw-addr: sets a static gateway address in the uplink network
UmerF2Maker Saga

Reply 1 year ago

thanks very much for the reply.

i have tried different settings but they dint work as expected. Also i saw a similar request recently on Martin's github page and he replied that ESPs with this firmware can not act as true seamless repeaters. they have to broadcast the downlink ssid on a different network range i.e.


1 year ago

Everything appears to be configured correctly but I get a reason 15 disconnect. Here is what i get after it starts:


state: 2 -> 0 (0)


state: 0 -> 2 (b0)

state: 2 -> 3 (0)

state: 3 -> 5 (10)

add 0

aid 6


state: 5 -> 2 (fc0)

rm 0

disconnect from ssid ATT7i9w6e3, reason 15

Did I setup something wrong? Your help would be greatly appreciated.