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This article mainly introduces "what is the method of Arduino and Android Bluetooth communication". In daily operation, I believe many people have doubts about what is the method of Arduino and Android Bluetooth communication. Xiaobian consulted all kinds of materials and sorted out simple and easy to use operation methods. I hope to help you answer the doubts of "what is the method of Arduino and Android Bluetooth communication"! Next, please follow the small series to learn together!

Some basic concepts about Bluetooth module Bluetooth master and slave

Host: able to initiate scanning and match slave modules

Slave: Can only be scanned and matched

A module can be both master and slave

AT mode

AT mode of Bluetooth is understood as setting mode. In setup mode, we set the following important parameters of Bluetooth:

Bluetooth module name. The name of your Bluetooth device when it is scanned by another device;

If it is a master-slave integrated module, its role can be set in AT mode;

Set password;

Communication baud rate. Note that the baud rate is different in AT mode and in working mode.

In AT mode, Bluetooth modules cannot be scanned and matched.

working mode

In this mode, Bluetooth can scan, be scanned, match, and be matched. This is a mode opposite to AT mode, in which the Bluetooth module can no longer be set.

list of elements

Zduino UNO R3

OpenJumper Bluetooth V2.0

OpenJumper Bluetooth V2.0 Introduction

OpenJumper Bluetooth V2.0 core module belongs to HC-05 master-slave module in HC series Bluetooth module. That is, the master-slave integration, through AT settings can change its role;

This module only supports SPP (Serial Port Profile) specification, so it can only realize "wireless serial port" communication function, and cannot support functions like Bluetooth headset or Bluetooth keyboard;

In order to connect the module correctly, you need to know the following important parameters:

AT mode

Serial port baud rate: 38400bps, stop bit: 1 bit, check bit: none

working mode

Serial port baud rate: 9600bps, stop bit: 1 bit, check bit: none

Meaning of indicator light

The module has two LEDs: State, status indicator, Link, connection indicator. Their flashes are defined as follows:

State

Flash (0.5s interval): Search status or wait for external links

Slow Flash (1s interval): Bluetooth Settings Mode

Double flash (bright twice at 0.5s interval, off for 3s): pairing successful, communication possible, supplement required

Link

Chang Liang: Pairing successful, communication possible

AT Settings

1. Write AT command setup program as follows;

/* * OpenJumper Bluetooth v2.0 AT mode setup code * updated by madmatrix */#define LED 13void setup(){ pinMode(LED,OUTPUT); Serial.begin(38400); //The baud rate in AT mode must be this value, otherwise it will fail to be set delay(100); Serial.println("AT"); delay(100); Serial.println("AT+NAME=My Bluetooth Test");//name module name delay(100); Serial.println("AT+ROLE=0");//Set master-slave mode: 0 slave, 1 master delay(100); Serial.println("AT+PSWD=1234");//Set pairing password delay(100); Serial.println("AT+UART=9600,1,0");//Set baud rate to 9600 in operation mode, stop bit 1, check bit absent delay(100); Serial.println("AT+RMAAD");//Empty pairing list}void loop(){ digitalWrite(LED, HIGH); //you can adjust the delay here every time you upload the program //Confirm that the program has been uploaded to arduino by observing the LED flashing interval delay(1000); digitalWrite(LED, LOW); delay(1000);}

2. Upload programs to arduino without Bluetooth module connected;

If Bluetooth is powered on at this time, and the serial port cable is connected to the serial port of Arduino, it will occupy the only serial port of Arduino uno (pins 0 and 1), and the program will not be uploaded to Arduino;

Although the computer and arduino are connected via usb, the usb is actually connected to the serial port through a converter chip on the arduino, so essentially the computer is still connected to the arduino via serial port.

3. Connect Bluetooth and arduino, pay attention to connect the AT pin of Bluetooth module to vcc (high level), at this time the State light of Bluetooth module flashes slowly (interval 1s), indicating entering AT mode. Once connected, press the Arduino reset button. Wait until the RX and TX LEDs on the arduino stop flashing and the Bluetooth module is set. Note that the flashing frequency of the State indicator remains unchanged;

You can also unplug the usb and plug it in without pressing the reset button. This process is equivalent to pressing the reset button. They both restart arduino, running programs that have been uploaded to the dashboard again;

At this time, because the Bluetooth module is connected to the arduino through the serial port, the output of Serial.println in the program is sent to the Bluetooth module through the serial port, thus achieving the purpose of setting Bluetooth;

In the first step, we set the baud rate to 38400bps, which is used to communicate with the Bluetooth module in AT setting mode. If it is set to 9600, the setting will fail.

4. Unplug the AT pin and VCC pin of the Bluetooth module and upload the working code to the arduino.

Unplug the AT pin line, and let the AT pin be empty. The Bluetooth module will enter the working mode when it is powered on next time.

At this time, the serial port baud rate in the working code should be set to 9600bps, which is the baud rate under the working state of the Bluetooth module. Note that the serial port communication baud rate in the working code should also be 9600bps.

5. The Bluetooth module is powered on (VCC pin is turned on), but the AT pin remains suspended. At this time, the State light of the Bluetooth module flashes (0.5s interval), indicating that it enters the search state, and the mobile phone can be used for pairing.

test

1. Write a simple piece of work code

#define LED 13void setup() { Serial.begin(9600); pinMode(LED, OUTPUT);}void loop() { char val; val = Serial.read(); if (val != -1) { Serial.print("Arduino answer: Cogito Ergo Sum! "); } digitalWrite(LED, HIGH); delay(2000); digitalWrite(LED, LOW); delay(2000);}

2. Download a small software called "Bluetooth serial port" on Android phone, install it, open the software, and then see the following interface:

Modify mode to "Session Mode"

Click Connect. In the pop-up window, click "Scan Device." No accident, you will see the name of the Bluetooth module you set, and then select:

Wait for the software to pop up the prompt "Connect to xxx", then look at the indicator light of Bluetooth module, at this time Link and other lights are always on, and the State light enters double flashing state.

So you can start the "conversation", just enter a paragraph of text, you can get a pre-set answer in our code:

At this point, the study of "What is the method of Arduino and Android Bluetooth communication" is over, hoping to solve everyone's doubts. Theory and practice can better match to help everyone learn, go and try it! If you want to continue learning more relevant knowledge, please continue to pay attention to the website, Xiaobian will continue to strive to bring more practical articles for everyone!

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