HC-05 bluetooth module interference with heart beat sensor

Other Hardware Sensors
1

Okay, So I should start this off by telling you all I'm a massive noob at this arduino stuff. I was only introduced to it about a month ago for a university project.

Anyway, for this project I decided to make a heart beat monitor that connects to an app which I have to make for your android phone. The app would connect to the board via the HC-05 bluetooth sensor.

here is the wire layout for the heart beat sensor:

Purple wire: A0
Ground: ground
Power: 5v

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The layout for the bluetooth module goes as follows:

Power: 3.3V (Although on the below diagram it says 5v, already taken by the other sensor)
Ground: Ground
RXD: RX0
TXD: TX1 (I believe the RX and TX connects are incorrect on the below diagram)

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Once I load the code onto the arduino board, I seem to get some interference caused by the HC-05 module. When I run the heart rate monitor without the bluetooth module I get correct outputs and the heart beat is displayed correctly. However, whenever I run the 2 modules together, the heart rate sensor seems to pick up a false pulse without any human interaction with it.

Has anyone encountered this problem before / anyone got any ideas on how to fix this issue?

I reached out on reddit and a kind user got back to me and they suggested that the heart beat sensor and the BT module together were sourcing too much current from the arduino? is this likely to be the issue?

Thank you for your time
A noob

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callumbuttery:
Power: 3.3V (Although on the below diagram it says 5v, already taken by the other sensor)

This is rubbish. If you can't find a way to share the 5v pin, use one of the other 5v pins. Improper power for Bluetooth may not be the cause of your problem, but it is surely the first thing that needs to be rectified.

I think if Bluetooth was prone to putting out some sort of interference, everybody would know about it by now. I therefore suspect Bluetooth is innocent.

I know nothing about the sensor but, if it is made for Arduino, it is very likely to be OK with Arduino + Bluetooth. Your problem may be in your power supply, about which you say nothing.

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The "interference" is probably because he has the HC-05 going to pins 0 and 1 thereby "interfering" with what he is writing to the Serial Monitor.

In addition, there is no voltage divider for RX of the HC-05.

No wonder it does not work. ::slight_smile:

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