Adding bluetooth module

Projects General Guidance
1

Hello! I have an automatic irrigation system and i want to add a bluetooth module hc05 to it too. I am not sure how because this is my first time using bluetooth module. Do i have to use resistors? And where should i put the cables? At which pins? The gnd should go to gnd, the vcc to 3.3v, the rx to 0(rx) pin of the board and the tx to 1(tx) pin of the board?
Also i didnt change the code either because i am not sure how so i would love some help with that too please.

void setup() {
  pinMode(3, OUTPUT);
  pinMode(6, INPUT);
}
void loop() {
  water = digitalRead(6); 
  if (water == HIGH)
  {
    digitalWrite(3, LOW);
  }
  else
  {
    digitalWrite(3, HIGH);
  }
  delay(400);
}
![image|375x500](upload://2FPqlbPT3pq4ToBn2xqZYshVKPz.jpeg)

image
image3024×4032 2.84 MB

image
image3024×4032 2.54 MB

image
image3024×4032 2.18 MB

3

Make a temporary project just operating and learning bluetooth. Use simple example code. When You master that You'll surely manage to add the relevant BT code into Your existing projec.

4

No, Tx to Rx and Rx to Tx.

You might find the following background notes useful.

It's getting a bit thick but you may find that the orders on P1 and the pictures on P5 are all you actually need.

5

Cant i connect the vcc of the module to the 3.3v of the board without the level shifter?

6

No.
The divider is for the 5v Arduino Tx signal into 3.3v Bluetooth Rx. It has nothing to do with VCC.
Read the back of the module. It should explain all you need. Also the above-mentioned guide.

8

I suppose I should have added previously that running Bluetooth off Arduino's 3.3v is a truly stupid idea, and essentially the preserve if the illiterate. Further, you only need one voltage divider, and that is on Arduino Tx. Arduino is perfectly happy to Rx 3.3v signals from Bluetooth. I might also point out that this "level shifter" need be no more than a 1k/2k voltage divider. That is what everybody actually uses and there is no need to be blinded by technobabble.
AND just in case you haven't already done it, don't panic. While it is good practice to use the divider, I have never heard of anyone actually frying their Bluetooth because they didn't, and about half the pictures on Google don't show a divider anyway.

9

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.