I have a school project that help babies who has a heart problem, I'm using an Arduino UNO R3, HC-05 Bluetooth and pulse Oximeter MAX40100(RCWL-0530), and I'm using the library at https://github.com/oxullo/Arduino-MAX30100pariculary MAX30100_debug.ino, when I tried to run it in that way:

VCC --> 3v3
SCL --> A5
SDA --> A4
INT --> D2

it was stuck at Initializing MAX30100... then I tried to connect it using a logic level converter (note: I couldn't find any in my country and it's impossible to buy from internet so I made one using this datasheet twice one for SDA and one for SCL), so it's showing this failure in the serial monitor

Failed to initialize the HRM sensor
ERROR: Failed to initialize pulse oximeter

(Note: I'm sure about connecting that Logic level converter)
So I need help in that

  • The MAX30100 is for 3.3v and the MAX40100 is for 3.3v and 5v. Which one do you have? Can you give a link to the RCWL-0530 module? Is there a schematic for it? Which mosfet do you use for the level converter? If you have the possibility to run the arduino uno at 3.3v, that will also work. For the i2c bus, start with a i2c scanner: playground.arduino.cc/Main/I2cScanner – Jot Jan 25 at 8:47

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