I am unable to get the MAX30100 sensor to work
It keeps throwing the following error:

16:06:32.936 -> Initializing...
16:06:32.936 -> MAX30105 was not found. Please check wiring/power.

I am using the Sparkfun library Example sketch "Example5_HeartRate"

As far as I understand the breakout board for the MAX30100 is a bit buggy - By which I mean the internal pullup resistors are connected to 1.8V for some reason instead of 5V

I have used MAX30100 before and had faced the same issue. However, after scouring the internet for hours I found this helpful article: https://reedpaper.wordpress.com/2018/08/22/pulse-oximeter-max30100-max30102-how-to-fix-wrong-board/

I want to use another MAX30100 sensor and have followed the above article again and have done the said changes to my sensor which resulted in the board being detected at address 0x57 when I run the i2c scanner. However, unlike the previous time, the Example sketch did not run as expected.

I even tried this solution: https://github.com/oxullo/Arduino-MAX30100/issues/51#issuecomment-391193292

But kept receiving the same error message.

The pin connections are: ARDUINO -> MAX30100/MAX300102
3V3 -> VIN
SDA (A4)-> SDA\
SCL (A5)-> SCL

I need help asap. Thank you in advance!

I hope the links mentioned are helpful for someone else.

3 Answers 3


This video might help you, in this video, an Indian guy explained the issue in detail with the help of the max30100 sensor schematic diagram, and solved it in two ways. https://youtu.be/ZqdmA4NAqb0

  • 1
    It would be good for you to summarize the important point from the video in case the video disappears in the future.
    – timemage
    Commented Mar 18, 2021 at 17:04

Check out this link. I guess it will work I had the same MAX30100 module what i did was removed those 4.7k resistors mounted through hole resistors on breadboard and pull-uped them using 5V and it was working fine for me


I had similar trouble with a cheap board (RCWL-0531). Used the same “How to fix wrong board” fix you mentioned (pictured).enter image description here Which worked ... sort of ... Achieved terrible sensing stability (both HR and O2). I read the comments in the sample code about Uno boards (which I had started out on) having insufficient capacity to handle the full sample data, so migrated to ESP32. Still not great. Gave up and bought a Sparkfun MAX30105, still connected to an ESP32 and OLED display. Immediately a different experience, much higher quality but I don't know why. I have some "still to-do" ideas to investigate the MAX30102_by_RF library and also to use a more capable processor (e.g., Due) to see if the signal processing capability can be cranked up. Hope this helps - you're not alone.

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