Tag Archives: Wireless

HC-05 Serial Bluetooth Module interface with Arduino

Features

Typical ‐80 dBm sensitivity
Up to +4Bm RF transmit power
3.3 to 5 V I/O and RoHS Compliant
PIO (Programmable Input/Output) control
UART interface with programmable baud rate
Inbuilt/Integrated antenna
Auto‐connect to the last device on power as default
Permit pairing device to connect as default
Auto‐pairing pin code: ”1234” as default (which can be changed)
CSR Bluetooth Chip Solution
Bluetooth Spec v2.0 EDR Compliant with V2.0.E.2 of specification for both 2Mbps and 3Mbps modulation modes
Full Speed Bluetooth Operation with Full Piconet Support and Scatternet Support
Support for 8Mbit External Flash On-board
Support for 802.11 Coexistence

Pinout

State: It is status indicator pin. When the HC05 is not connected to or not paired with any other Bluetooth device, signal at this pin goes Low. During this state the on-board LED flashes continuously which indicates that the module is not paired with any device. When HC05 is paired or connected with any Bluetooth device, the pin status goes High. During this state, on-board LED blinks with a constant delay say for example 2 seconds delay which indicates that the module is paired.

RXD: Receive pin of UART interface for communication

TXD: Transmit pin of UART interface for communication

GND: Ground pin

Vcc: Supply voltage of 3.3V or 5VDC

Key (or EN): When this pin is high, the module is disabled & will not be connected with any module. When this pin is open or connected to ground or kept open, the module is enabled & it can be connected/communicate.

Apart from pins, you will find a small push button on HC05. When you press the button for 1 second, HC05 will enable AT command mode. During AT command mode you can change different parameters of HC05, but while changing parameters the HC05 shouldn’t be connected/paired with any device.

Arduino Connection

HC05	Arduino
Vcc	5V
GND	GND
TXD	D10
RXD	D11

Normally, people connects HC05 TXD & RXD to Arduino RX(D0) & TX(D1), but in that case if you want to upload any code using USB port then you have to remove connection from D0 & D1 otherwise you will get code upload error. To avoid this issue there is one best solution as library called ‘SoftwareSerial’. Using SoftwareSerial library we can configure any two DIO as Tx & Rx. In above connection diagram, HC05 Tx & Rx are connected to Arduino pins D10 & D11 which to be assigned as Rx & Tx respectively.

Arduino Code

#include SoftwareSerial BTserial(10, 11);
char data;

void setup()
{
Serial.begin(9600);
Serial.println("Beat Your Bit");
BTserial.begin(9600);
BTserial.println("Beat Your Bit");
}

void loop()
{
if (BTserial.available())
{
data=BTserial.read();
Serial.print(data);
}
if (Serial.available())
{
data=Serial.read();
BTserial.print(data);
}
}

#include SoftwareSerial BTserial(10, 11);

char data;

void setup()

{

Serial.begin(9600);

Serial.println("Beat Your Bit");

BTserial.begin(9600);

BTserial.println("Beat Your Bit");

}

void loop()

{

if (BTserial.available())

{

data=BTserial.read();

Serial.print(data);

}

if (Serial.available())

{

data=Serial.read();

BTserial.print(data);

}

You can download above code from here.

Explanation of code:

#include : As you can see SoftwareSerial library is included, it is available in Arduino IDE

SoftwareSerial BTserial(10, 11); : anyname(RX, TX); i’ve give name BTserial, D10 pin as RX & D11 as Tx

char data; : variable where incoming data will be stored, for better execution data will be first stored in a variable then will be processed.

Serial.begin(9600); begin serial communication with Arduino IDE

Serial.println(“Beat Your Bit”); print custom message on serial monitor to confirm serial communication has been initiated

BTserial.begin(9600); begin serial communication using dedicated pins (D10 & D11)

BTserial.println(“Beat Your Bit”); transmit custom message on HC05 paired device to confirm serial communication with HC05 has been initiated

if (BTserial.available()) [if any data available from HC05 then]
data=BTserial.read(); [store received data in ‘data’ variable]
Serial.print(data); [print received data on serial monitor of Arduino IDE]
if (Serial.available()) [if any data available from serial monitor then]
data=Serial.read(); [store received data in ‘data’ variable]
BTserial.print(data); [transmit received data on HC05]

As explained, this code exchanges data between HC05 and Arduino IDE serial monitor. We can see data received on serial monitor but to read the data received on HC05, we have to use an android app or any terminal application which can be connected with HC05 using Bluetooth. Here we are going to use android app to test Arduino-HC05 connection & data exchange. I used Arduino Bluetooth Control app which have many add on features & easy to use. It has serial terminal, arrow keys, buttons, slider, accelerometer & voice control features.

Connect circuit as shown in connection diagram, upload code and connect/pair HC05 with your smartphone. If you are using/pairing HC05 for first time then default pairing PIN may be 1234, you can change it later using AT commands. Open Arduino Bluetooth Control App & select paired HC05. Open terminal windows in app & serial monitor in Arduino IDE with mentioned baud-rate. Write any text in Arduino IDE serial monitor & press enter, you will receive same text in terminal window of Arduino Bluetooth Control app. Vice versa, write in app and send it to Arduino IDE serial monitor.

Change HC05 settings

You can change HC05 default settings like Bluetooth display name, pairing PIN, baud rate etc. As mentioned in Pin-out details, you have to put HC05 in AT command mode by pressing the push button while power up the module but make sure it is not connected with any other Bluetooth device.

How to put HC05 in AT command mode:

1. Disconnect HC05 form power, Remove the +5V connection to HC05.
2. Press and hold the push button switch on HC05
3. Re-connect HC05 Vcc to +5V (while still pressing the button switch), HC05 on-board LED should turn ON.
4. Release the push button switch and the LED should be blinking at interval of two seconds. It indicates that your are now in AT command mode. Now open serial monitor & give AT commands from there.

Some useful AT commands:

AT : Simple feedback request. If communication is working fine then it will return “OK”

AT+VERSION : This returns the firmware version.
For Example:
“+VERSION:2.0-20100601
OK”

AT+STATE : This returns the current state of the module.
For Example:
“+STATE:INITIALIZED
OK”

AT+ROLE : Valid values are 0~Slave, 1~Master, 2~Slave-Loop.
Return example:
“+ROLE:0
OK”
(To change to Master Mode, enter AT+ROLE=1, returns “OK”)

AT+UART : It returns the baud rate used by the HC05 in communication mode. Default it will be 9600 mostly.
Return example:
“+UART:9600,0,0
OK”
(To change the baud rate to 19200 : AT+UART=19200,0,0. Returns “OK”)

AT+NAME : The command AT+NAME? only works in AT command mode. If HC05 is not responding on AT+NAME? then put HC05 in AT command mode as procedure mentioned in tutorial.
Return when AT+NAME? is given:
“+NAME:HC-05
OK”
(To change name : AT+NAME=BeatYourBit, Returns “OK”)

You can find all AT commands list from here.

I hope you liked this tutorial, now you can add Bluetooth interface in your project & expand the features. Further you can display values on display, data exchange with another wireless modules like RF & WiFi. Give your feedback about this tutorial in Contact, Your feedback will be appreciated.

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Infrared transmitter & receiver interface with Arduino

Specifications & Features

IR LED:

Forward current (IF) is 100mA (normal condition) and 300mA (max.)
1.5A of surge forward current
1.24v to 1.4v of forward voltage
Temperature for storage and operation varies from -40 to 100 ℃
Soldering Temperature should not exceed 260 ℃
Power Dissipation of 150mW at 25℃ (free air temperature) or below
Spectral bandwidth of 45nm
Viewing angle is 30 to 40 degree
Maximum wavelength is 940nm
RoHS certified

TSOP382 IR Receiver:

Very low supply current
Photo detector and pre-amplifier in one package
Internal filter for PCM frequency
Improved shielding against EMI
Supply voltage: 2.5 V to 5.5 V
Improved immunity against ambient light
Insensitive to supply voltage ripple and noise
Component in accordance to RoHS 2002/95/EC and WEEE 2002/96/EC

IR Receiver Connection With Arduino

As shown in figure, an IR receiver is connected with Arduino UNO. Here we will use an IR remote which is most commonly used for Arduino projects, in your project you can use any remote & can make your own remote as per application. In market you can get a kit which contains an IR Remote, IR Receiver, IR LED for you DIY purpose & jumper wires as shown in image.

Test Program For IR Remote

#include "IRremote.h"
int receiver = 11; // IR receiver input to Arduino Digital Pin 11
IRrecv irrecv(receiver);
decode_results results;
void setup()
{
Serial.begin(9600);
Serial.println("IR Remote Button Decoder");
irrecv.enableIRIn(); // Start receiving IR
}
void loop()
{
if (irrecv.decode(&results)) // Receive IR value
{
translateIR();
irrecv.resume(); // Receive the next value
}
}
void translateIR() //Loop activated when IR code received
{
switch(results.value)
{
case 0xFF629D: Serial.println("FORWARD"); break;
case 0xFF22DD: Serial.println("LEFT"); break;
case 0xFF02FD: Serial.println("-OK-"); break;
case 0xFFC23D: Serial.println("RIGHT"); break;
case 0xFFA857: Serial.println("REVERSE"); break;
case 0xFF6897: Serial.println("1"); break;
case 0xFF9867: Serial.println("2"); break;
case 0xFFB04F: Serial.println("3"); break;
case 0xFF30CF: Serial.println("4"); break;
case 0xFF18E7: Serial.println("5"); break;
case 0xFF7A85: Serial.println("6"); break;
case 0xFF10EF: Serial.println("7"); break;
case 0xFF38C7: Serial.println("8"); break;
case 0xFF5AA5: Serial.println("9"); break;
case 0xFF42BD: Serial.println("*"); break;
case 0xFF4AB5: Serial.println("0"); break;
case 0xFF52AD: Serial.println("#"); break;
case 0xFFFFFFFF: Serial.println("REPEAT");break;
default:
Serial.println("other button");
}
delay(500); //Some delay before repeat
}

#include "IRremote.h"

int receiver = 11; // IR receiver input to Arduino Digital Pin 11

IRrecv irrecv(receiver);

decode_results results;

void setup()

{

Serial.begin(9600);

Serial.println("IR Remote Button Decoder");

irrecv.enableIRIn(); // Start receiving IR

}

void loop()

{

if (irrecv.decode(&results)) // Receive IR value

{

translateIR();

irrecv.resume(); // Receive the next value

}

void translateIR() //Loop activated when IR code received

{

switch(results.value)

{

case 0xFF629D: Serial.println("FORWARD"); break;

case 0xFF22DD: Serial.println("LEFT"); break;

case 0xFF02FD: Serial.println("-OK-"); break;

case 0xFFC23D: Serial.println("RIGHT"); break;

case 0xFFA857: Serial.println("REVERSE"); break;

case 0xFF6897: Serial.println("1"); break;

case 0xFF9867: Serial.println("2"); break;

case 0xFFB04F: Serial.println("3"); break;

case 0xFF30CF: Serial.println("4"); break;

case 0xFF18E7: Serial.println("5"); break;

case 0xFF7A85: Serial.println("6"); break;

case 0xFF10EF: Serial.println("7"); break;

case 0xFF38C7: Serial.println("8"); break;

case 0xFF5AA5: Serial.println("9"); break;

case 0xFF42BD: Serial.println("*"); break;

case 0xFF4AB5: Serial.println("0"); break;

case 0xFF52AD: Serial.println("#"); break;

case 0xFFFFFFFF: Serial.println("REPEAT");break;

default:

Serial.println("other button");

}

delay(500); //Some delay before repeat

}

You can download above code from here.

Code explanation: Here we will use remote as shown in first image of tutorial which is easily available in market. You need IRremote library in this code which is available in library manager. IR receiver signal pin is connected to Pin 11 of Arduino. You need to define two variables; IRrecv irrecv(receiver);- to receive values from IR module, decode_results results;-to compare results value & print text accordingly.

You need to enable receiving using irrecv.enableIRIn(); in void setup() loop which runs in first cycle only. In void loop(), it continuously scans if IR module receives any signal. If it finds any signal then it calls translateIR() loop & then receives new value.

In translateIR() loop switch function is used which compares received value with preset values & print text accordingly. For example, When you press Up/Forward key on remote than remote will transmit a hex value FF629D which is received by IR module, compared in switch condition & print FORWARD in serial monitor. Each key has different value as per make. After printing it will complete the loop with delay of 500ms. Each key of remote has different hex value, you can try other remotes by removing switch condition & directly print hex value in serial monitor, for example;

#include "IRremote.h"
int RECV_PIN = 11;
IRrecv irrecv(RECV_PIN);
decode_results results;
void setup()
{
Serial.begin(9600);
Serial.println("Enabling IRin");
irrecv.enableIRIn();
Serial.println("Enabled IRin");
}
void loop() {
if (irrecv.decode(&results)) {
Serial.println(results.value, HEX);
irrecv.resume(); // Receive the next value
}
delay(500);
}

#include "IRremote.h"

int RECV_PIN = 11;

IRrecv irrecv(RECV_PIN);

decode_results results;

void setup()

{

Serial.begin(9600);

Serial.println("Enabling IRin");

irrecv.enableIRIn();

Serial.println("Enabled IRin");

}

void loop() {

if (irrecv.decode(&results)) {

Serial.println(results.value, HEX);

irrecv.resume(); // Receive the next value

}

delay(500);

}

You can download above code from here.

You can make your own IR remote using a keypad, IR LED & Arduino as per your requirement. Receive key value, compare it with preset & write value on IR LED. In that case you need to add ‘irsend.sendNEC(0x34895725, 32);}’ to transmit the value where 34895725 is the value to transmit & 32 is size of IR signal. For transmitter, IR LED must be connected in Pin 3 as it is defined in IRremote library. (All IR send & receive examples are available in IRremote library).

Device control using IR

You can control device using IR remote/transmitter easily. In this test code, we will control 4 outputs on pin 7, 6, 5 & 4 using numerical keys on IR remote.

#include "IRremote.h"
#define first_key 0xFF6897
#define second_key 0xFF9867
#define third_key 0xFFB04F
#define fourth_key 0xFF30CF
int receiver_pin = 11;
int first_led_pin = 7;
int second_led_pin = 6;
int third_led_pin = 5;
int fourth_led_pin = 4;
int led[] = {0,0,0,0};
IRrecv receiver(receiver_pin);
decode_results output;
void setup()
{
Serial.begin(9600);
receiver.enableIRIn();
pinMode(first_led_pin, OUTPUT);
pinMode(second_led_pin, OUTPUT);
pinMode(third_led_pin, OUTPUT);
pinMode(fourth_led_pin, OUTPUT);
}

void loop() {
if (receiver.decode(&output)) {
unsigned int value = output.value;
switch(value) {
case first_key:
if(led[1] == 1) {
digitalWrite(first_led_pin, LOW);
led[1] = 0;
} else {
digitalWrite(first_led_pin, HIGH);
led[1] = 1;
}
break;
case second_key:
if(led[2] == 1) {
digitalWrite(second_led_pin, LOW);
led[2] = 0;
} else {
digitalWrite(second_led_pin, HIGH);
led[2] = 1;
}
break;
case third_key:
if(led[3] == 1) {
digitalWrite(third_led_pin, LOW);
led[3] = 0;
} else {
digitalWrite(third_led_pin, HIGH);
led[3] = 1;
}
break;
case fourth_key:
if(led[4] == 1) {
digitalWrite(fourth_led_pin, LOW);
led[4] = 0;
} else {
digitalWrite(fourth_led_pin, HIGH);
led[4] = 1;
}
break;
}
Serial.println(value);
receiver.resume();
}
}

#include "IRremote.h"

#define first_key 0xFF6897

#define second_key 0xFF9867

#define third_key 0xFFB04F

#define fourth_key 0xFF30CF

int receiver_pin = 11;

int first_led_pin = 7;

int second_led_pin = 6;

int third_led_pin = 5;

int fourth_led_pin = 4;

int led[] = {0,0,0,0};

IRrecv receiver(receiver_pin);

decode_results output;

void setup()

{

Serial.begin(9600);

receiver.enableIRIn();

pinMode(first_led_pin, OUTPUT);

pinMode(second_led_pin, OUTPUT);

pinMode(third_led_pin, OUTPUT);

pinMode(fourth_led_pin, OUTPUT);

}

void loop() {

if (receiver.decode(&output)) {

unsigned int value = output.value;

switch(value) {

case first_key:

if(led[1] == 1) {

digitalWrite(first_led_pin, LOW);

led[1] = 0;

} else {

digitalWrite(first_led_pin, HIGH);

led[1] = 1;

}

break;

case second_key:

if(led[2] == 1) {

digitalWrite(second_led_pin, LOW);

led[2] = 0;

} else {

digitalWrite(second_led_pin, HIGH);

led[2] = 1;

}

break;

case third_key:

if(led[3] == 1) {

digitalWrite(third_led_pin, LOW);

led[3] = 0;

} else {

digitalWrite(third_led_pin, HIGH);

led[3] = 1;

}

break;

case fourth_key:

if(led[4] == 1) {

digitalWrite(fourth_led_pin, LOW);

led[4] = 0;

} else {

digitalWrite(fourth_led_pin, HIGH);

led[4] = 1;

}

break;

}

Serial.println(value);

receiver.resume();

}

You can download above code from here.

As shown in code, it compares received signal with preset values of IR remote control numeric key hex values. You can change the value according to your remote if you know hex values of each button, If you don’t know than use second code in tutorial which is IR remote test code & set it in #define functions.

I hope this tutorial will be helpful to use IR transmission & receiving in your DIY stuff. Give your feedback about this tutorial in Contact, Your feedback will be appreciated.

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Career Frequency	Standard Applications (AGC2/AGC8)	Very Noisy Environment (AGC4)
30 kHz	TSOP38230	TSOP38430
33 kHz	TSOP38233	TSOP32433
36 kHz	TSOP38236	TSOP38436
38 kHz	TSOP38238	TSOP38438
40 kHz	TSOP38240	TSOP38440
56 kHz	TSOP38256	TSOP38456