HELP! Module BT HC-05 doesnt work

Other Hardware Sensors
1

Hello,

Well my bt module was working well and everything was OK.
But now it doesnt work anymore, the power led is on and I can connect it with my phone but it can't reveice or send data. I've checked the wiring, the problem doesnt come from here, so please do you have any idea from where the problem can come ?
Thank You
Steewz

2

My crystal ball sees that you have connected the BT device to the 3.3volt power pin of the Nano,
and have used RX/TX pin 0,1 for data.

Both will give problems.

The BT module needs 3.6-6volt power (5volt is fine).
The RX/TX pins of the Nano are already used by the USB<>Serial chip.
You should used SoftwareSerial on different pins.
And you should use resistors on the RX pin of the BT module, to protect the 3.3volt BT logic from the Nano's 5volt logic.
Many examples on the web.

12 servos could be easier wired/controlled/powered with a PCA9685 breakout board (Adafruit, ebay).
See second small picture.
Leo..

3

Wawa:
The BT module needs 3.6-6volt power (5volt is fine).
The RX/TX pins of the Nano are already used by the USB<>Serial chip.
You should used SoftwareSerial on different pins.
And you should use resistors on the RX pin of the BT module, to protect the 3.3volt BT logic from the Nano's 5volt logic.

This is exactly what I did but it doesnt work, I've also tried to reset it with the AT mode but the module doesnt respond

4

i've tried smt else, using the serial port to send/receive a text with a serial application on my phone.
When i send a text from my PC, I can see it on the phone but when I send something from the phone it doesnt work, so i guess the problem is coming from the TX pin.
Can I fix this ?

Here's the code I used

#include <SoftwareSerial.h>
#define rxPin 11 // Broche 11 en tant que RX, à raccorder sur TX du HC-05
#define txPin 10 // Broche 10 en tant que TX, à raccorder sur RX du HC-05
SoftwareSerial mySerial(rxPin, txPin);
void setup()
{
 // define pin modes for tx, rx pins:
 pinMode(rxPin, INPUT);
 pinMode(txPin, OUTPUT);
 mySerial.begin(9600);
 Serial.begin(9600);
}
void loop()
{
int i = 0;
char someChar[32] = {0};
// when characters arrive over the serial port...
if(Serial.available()) {
 do{
 someChar[i++] = Serial.read();
 delay(3);
 }while (Serial.available() > 0);
 mySerial.println(someChar);
 Serial.println(someChar);
}
while(mySerial.available())
 Serial.print((char)mySerial.read());
}
5

Steewz:
Well my bt module was working well and everything was OK.
But now it doesnt work anymore,

Steewz:
When i send a text from my PC, I can see it on the phone but when I send something from the phone it doesnt work,

Really.....
It sounds like slack wiring, probably a cheapo breadboard.

6

Nick_Pyner:
Really.....
It sounds like slack wiring, probably a cheapo breadboard.

I've tried with different wires and without any breadboard but I have the same result

7 
 pinMode(rxPin, INPUT);
pinMode(txPin, OUTPUT);

Didn't see that in the SoftwareSerial examples.
Why did you add those lines.
Leo..

8

Still nothing my module cannot transmit data

9

You have said it works before but it doesn't any more. IF that is true, the following is true

  1. the code is kosher - providing you have not changed it.
  2. the wiring is correct in principle - providing you have not changed it.
    and the only causes left are
  3. the wiring is not correct in practice OR
  4. Bluetooth is faulty.
  5. You have indeed changed the code and/or the wiring

I think your code is verbose, but I guess the junk is just that and merely redundant rather than harmful - and you did say it worked.