How to install 802.11 ac USB wifi modules?

2022-01-02/ By Admin

Introduction of the 802.11 ac USB wifi module

Today with the Internet of Things (IoT), which is the connection to everyday objects (cars, refrigerators, televisions, lights, gates, etc.)? 802.11 ac USB wifi module always provides instantaneous information.

And being commanded anywhere in the world through the internet makes that there is persistent communication free from failures. However, some devices cannot reach the Wi-Fi signal provided by the routers, leaving this equipment offline or with a very large instability.

How does the 802.11 ac USB wifi module work?

The 802.11 ac USB wifi module transmits and receives data at a certain frequency. It is called the Channel (channel). Also, for two or more transceiver modules to communicate. They must be on the same channel. This channel can be any frequency in the 2.4GHz ISM band or, to be more precise, it can be between 2400 to 2.525GHz.

Specifications of the 802.11 ac USB wifi module

  • Operation speed of up to 2Mbps, which can be used even in high-quality VoIP applications;
  • Also, Selectable baud rates between 2Mbps, 1Mbps, or 250Kbps over the air;
  • Moreover, Low consumption, with a supply voltage of 1.9 to 3.6V.
  •  And a current in Power Down mode of only 1uA, ideal for devices that operate on batteries;
  • Furthermore, Integrated voltage regulator;
  • In addition, 5V tolerant inputs;
  • Also, Non-critical crystal, with a tolerance of +/- 60 PPM;
  • Moreover, High-efficiency GFSK 802.11 ac USB wifi module
  • Furthermore, Anti-interference ability;
  • In addition, Particularly suitable for industrial control applications;
802.11bgn Wifi Module

802.11 ac USB wifi module problems solutions

A solution to solve this problem, although not so cheap, is to install more routers, spending more money on equipment and labor to manage the entire network.

But with Mesh technology we can take advantage of the equipment already installed and transform them into a Wi-Fi signal repeater at no cost, ensuring that the signal reaches all equipment

When creating a Mesh network, we can take advantage of 802.11 ac USB wifi modules that are already controlling equipment and assign one more function which is the bridge to provide Wi-Fi signals to those devices that are out of range of the central router.

What is Mesh Networks and How They Work

traditional networks

In traditional Wi-Fi networks, there is a router called Access Point (AP) where the various points (stations) communicate exclusively with it.

The Access Point (AP) is responsible for managing the entire network. And prioritizing, providing IPs, connecting or disconnecting stations.

This concentration creates a disadvantage since the entire network depends exclusively on a central device to function.

And the distance of your 802.11 ac USB wifi module reach is the distance of the maximum network.

Thus, if a station is far from the AP, it may be out of range of the transmitted Wi-Fi signal, failing to communicate with the network

Traditional Network where it is possible to see that three devices cannot reach the Router's Wi-Fi signal

Mesh networks802.11 ac USB wifi module

It is a cheap and creative solution to extend the connection of devices where, in addition to receiving the signal. They also become a data provider, serving as a bridge to other devices creating a mesh very similar to a spider's web that all points are connected to at least two points.

And that the disruption of a node does not cause the communication to drop, as there is another pre-configured connection point and making the network self-organize almost instantly.

Mesh network. 802.11working in the network.

The 802.11 ac USB wifi module is an innovative solution since that point that cannot receive the direct Wi-Fi signal from the AP can bridge to another nearby device working. And taking advantage of an existing structure, not requiring the purchase of new equipment.

And working with redundancy since a broken connection does not affect the system where the network works in mesh and the broken point will quickly connect to another point instantly and is self-managed

According to official documentation from Espressif, the Mesh network can connect up to 100 nodes without system breaks or instability

802.11bgn Wifi Module 2022

802.11 ac USB wifi module in summary:

In the traditional 802.11 ac USB wifi module, the entire infrastructure is based on a true connection where the stations connect directly to the router.

And in the Mesh network, stations have a double function, obtaining. And providing data simultaneously, resulting in a network topology very similar to a spider's web. (in practice it is not the same as a web, but for didactic purposes. This definition embraces the idea of ​​a Mesh network).

Materials and requirements used

  • 802.11module
  • Also, 802.11 ac USB wifi module Module
  • Moreover, WiFi module ESP-01
  • Furthermore, IDE ARDUINO
  • painless Mesh LIBRARY

Building the Mesh Network

The developer of the Library used to create the Mesh Network painlessMesh. Homemade the programmer's life much easier, not having to worry about the structure or node breakage that might happen or in the management of the network, everything happens automatically.

The network is an Ad-Hoc network that does not require the management of new devices. The entry of a new device or the shutdown occurs automatically, organizing itself without warning or jumping to the administrator.

Installing the painlessMesh Library

In our tests, the best solution was to install the painlessMesh library through GitLab, where we found the most updated and stable library.


  • This code is very basic and serves as proof of concept and changes are welcome.
  • Also, Using the delay () function interrupts the code, making it impossible to carry out tasks in the background, causing the Mesh network to generate instability or even stop working.
  • Moreover, So, a solution is to use the Milis () function to perform a certain task or even use a task scheduler.

Installation problem solutions

If some devices do not connect to the network. Also, check if the SSID name and password are correctly entered;

Scan the 802.11 ac USB wifi module Analyzer mobile app. And you'll see that the entire Mesh network shares the same channel. The discrepancy of channels as a router between the Esp prevents the exchange of data until the Esp changes channels, this happens automatically.

Thus, to avoid network failure and delay in data transmissions, the user must configure the router so that “NO” changes the Wi-Fi channel automatically.

Notes and conclusion

In tests performed, the time to create the 802.11 ac USB wifi module is generally less than one minute.

The latency between hops is 10 to 30 milliseconds. And the time of this latency is directly related to the number of hops that exist within the Mesh network.


Optimize as much as possible the number of transmitted/received messages, remembering that our Esp modules are very limited both in processing and in memory, so we avoid messages and network breaks.