Hi, I have nucleo F401RE and max30100 sensor. the sensor dont get enough voltage apparently, i tried to use voltage regulator and it did not work. The led is on but i can not get information from the sensor. it worked with arduino nano perfectly.

[Eleon BORLINI]

Hi @YBuch.1​ , added STM32F4 topic since the question seems more related to the uC settings. Can you please share more detail on your connection (in terms of schematic and operating voltage)? Are you working at 1.8V or 3.3V)? I see from the MAX30100 datasheet that typ VDD = 1.8V (max 2.2V), VIR_LED+ = VR_LED+ = 3.3V. Regards

[YBuch.1]

Hi,

I connected the max30100 to 3v3 , gnd, scl, sda on the nucleo.

I also tried to connect the max to this voltage regulator: https://www.mouser.co.il/ProductDetail/Adafruit/757?qs=GURawfaeGuCFbCY6Rr8Yew==

and than to the nucleo but it did not worked.

what exactly the details you want me to share? here is the nucleo datasheet --

https://www.st.com/resource/en/user_manual/dm00105823-stm32-nucleo64-boards-mb1136-stmicroelectronics.pdf

page 63 is the relevant.

also found this - not sure if it can help:

https://github.com/oxullo/Arduino-MAX30100/issues/51 - this link is with the same issue but with arduino board.

thanks for your comment and wait to hear from you soon.. best regards !

[YBuch.1]

I am working with 3v3 volts as i know.. the nucleo 3v3 connection is connected to the max30100 connection of 3v3. Also the nucleo is connected to the computer with usb cable.

[Tesla DeLorean]

Sure they have got Nucleo manuals/datasheets...

What you're being asked for is a SCHEMATIC of what YOU have wired up, ie what goes where, how the supplies and grounds, etc connect.

Draw a diagram and photograph it, if that is easier to do. Not a picture of your boards with wires going everywhere.

The Adafruit 757 is a logic level converter, not a regulator.

Lot of the DISCO boards run closer to 3V, get a scope or multimeter check it.

5V should be available on the Arduino shield header if you're using a REGULATOR to drop the voltage

>>it worked with arduino nano perfectly.

Ok, show the wiring diagram that worked.

Understand that "working" / "not working" is an outcome, not a cause.

[Tesla DeLorean]

This is an engineering venue, more diagrams, less prose..

Common Grounds?

[YBuch.1]

hi

thanks for the comment, scheme attached. hope this is what you ment..

[YBuch.1]

Hi,

I attached my connection in the last comment.

I am attaching the max schematics .

thanks , looking forward for your answer.