How to operate mt7688an OpenWrt?

2022-01-02/ By Admin

What is the mt7688an OpenWrt?

In this project, you will learn how to communicate the mt7688an OpenWrt with Arduino and how to send data from Arduino to the server using the mt7688an wi-fi module.

In today's tutorial, we will learn how to communicate the Wi-Fi module with Arduino and see how Wi-Fi works. We're going to stream the data to the real world and display it as a graph.

We will transmit the temperature and humidity data of the air to the server using the DHT11 sensor and the MT7688AN Wi-Fi module.

About MT7688AN. Wi-Fi Module

Wifi Fidelity is a term common for products that use 802.11 technology. Wi-Fi networks operate at 11 Mbps or 54 Mbps data rates in the 2.4 GHz and 5 GHz unlicensed radio bands.

Wi-Fi-enabled devices can send and receive data wirelessly from locations with wireless access. Access points located in a Wi-Fi location transmit RF signals to Wi-Fi-enabled devices.

These Wi-Fi-enabled devices can receive the signal if they are within range of the access point. The data transfer rate depends on the speed of the access point's line.

Working principle of the MT7688AN. Wi-Fi module

Radio signals are the basic working principle of Wi-Fi. It is made up of three essential elements.

Working principle of the mt7688an OpenWrt

Radio signals are transmitted by antennas and routers, and they are received by Wi-Fi receivers such as computers.

mt7688an OpenWrt

MT7688AN. Wi-Fi Module

  • The Wi-Fi module has 8 pins arranged in 2 rows. Place the pins closest to the device input.
  • Also, The DHT module has 3 output pins.
  • Moreover, Data Pins – For digital signals
  • Furthermore, Vcc pin – 5V. power supply
  • In addition, GND pin – Ground pin
  • Also, Module-DHT11
  • mt7688an OpenWrt Communication with Arduino

Connect the circuit as follows:

  1. The Tx pin of the MT7688AN module connects to the D2 of the Arduino
  2. The MT7688AN module's CH-DO pin connects to the Arduino's 3V via a 10k resistor.
  3. Also, The Rx pin of the MT7688AN module is connected to the Arduino's D3 through the voltage divider as shown.
  4. Moreover, The MT7688AN module's RST pin connects to the Arduino's 3V (not shown in the schematic).
  5. Furthermore, The VCC pin of the mt7688an OpenWrt connects to the 3V of the Arduino.
  6. In addition, The GND pin of the MT7688AN node with the GND pin of the Arduino.
  7. Moreover, the entire circuit will be a combination of both steps above.

After completing the circuit follow as given. We see the results on the server. You will see the results in the “Public preview” section of the website.

The procedure for connecting the MT7688AN Wi-Fi module to the Arduino

1. First, users need to create an account on, then log in and click Start.

Wi-Fi MT7688AN with Arduino

2. Now go to the 'Channels' menu and click on the New channel option on the same page to continue processing.

mt7688an OpenWrt -elephant-Arduino-1

Now you will see a form to create a channel, fill in the Name and Description according to your own. Then fill in the 'Humidity' and 'Temperature' in labels 1 and 2, tick the checkboxes for these 2 labels and also the 'Make public' checkbox in the form below, and finally Save channel. Now your new channel has been created.


Now click on the ‘API Keys’ tab and save the Write and Read API keys, here we just use the Read key. You need to Copy this key to char * api_key in code.

mt7688an OpenWrt -elephant-Arduino-3

Code can communicate to display on LCD. You can connect to LCD as shown in the code and all the results show on LCD and can also be displayed on the monitor of the Arduino.

MT7688AN. Applications

  • mobile applications.
  • Also, Wi-Fi is common in business applications
  • Moreover, Wi-Fi is common in-home applications
  • Furthermore, the calculator application.
  • Also, Wi-Fi is common in the automotive segment.
  • to access the internet.
  • Wi-Fi is common in online meetings.

Advantages of the mt7688an OpenWrt

  • Wireless laptops that easy to move from place to place
  • Wireless Wi-Fi network communication devices can reduce the cost of connecting wires.
  • Wi-Fi setup and configuration is easier than cabling
  • It is completely secure and will not be interfered with by other networks
  • We can also connect to the internet through hotspots
  • We can connect to the internet wirelessly

Defect of the mt7688an OpenWrt

  • Wi-Fi generates radiation that harmful to human health
  • We have to disconnect from Wi-Fi whenever we are not using the server
  • There is a data transmission limitation, we cannot transmit data long distances.
  • Wi-Fi deployment is more expensive than wired connection system

The mt7688an OpenWrt is a very popular wifi module in Vietnam, using the mt7688an chip with integrated 2.4Ghz Wi-Fi that is easy to program directly on the chip. Currently, this line has many module versions, popularly common are ESP01, ESP07, ESP12.

Some pin-outboards make it easy to connect to peripherals such as Nodemcu, Wemos D1... In this article, I will guide you to familiarize yourself with the MT7688AN01 WIFI module.

mt7688an OpenWrt 2022

Functions of the mt7688an OpenWrt:

  1. Dimensions: 24.75mm x 14.5mm
  2. Also, Working voltage 3.3v
  3. Moreover, The built-in antenna on the module
  4. Furthermore, with power LED, TX led
  5. In addition, Operates 2 modes of WiFi transmitter and WiFi receiver at the same time
  6. AP, STA, AT + STA

When purchased, the AT command firmware is available at 115200 baudrate for easy communication with the peripheral (MCU)

Demo communication with PC

We will get acquainted with this module by communicating with the PC to send the test AT Command. Please pay attention to using the newly purchased module (with AT firmware available) to communicate. If you use the old module, buy it again, the previous user may have loaded another firmware, leading to the inability to communicate.

Protocol Operation of the mt7688an OpenWrt

Unlike UDP protocol, which can immediately send packets without establishing a connection, TCP requires establishing a connection before it starts sending data and terminating the connection when sending data is complete. Specifically, TCP connections have three phases:

  1. Set up a connection
  2. Data transmission
  3. End connection


To establish a connection, TCP uses a process embarked 3 Steps (3-way handshake ) before the client tries to connect to a server, the server must register a port and open that port for connections: this is called a passive open. Once a passive open has been established, a client can initiate an active open.