I am working on a gas flow sensor SFM4100. It's communcation protocol is i2c. And according to gasses bus adresses are changing. For o2 gas, address is 2.

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When I connected the all pins according to datasheet , raspberry pi doesn't detect i2c address. I tried both sudo i2cdetect -y 0 and sudo i2cdetect -y 1

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What is the reason of that ?

Also, my pin connection . Any help is appreciated.

  • 1
    Did you enable the I2C bus in raspi-config?
    – PMF
    Mar 23, 2021 at 12:16
  • What is reported by i2cdetect? Where is the photo clearly showing the connections you have made?
    – joan
    Mar 23, 2021 at 12:29
  • What are your pullup resistor values? Mar 23, 2021 at 12:40
  • Yes, i2c bus enabled. I think that is because of i2c device address. Raspberry pi 4 doesnt detect i2c addresses which are smaller than 3.@PMF
    – noobinmath
    Mar 23, 2021 at 12:44
  • I didn't use pull up resistor. @ElliotAlderson
    – noobinmath
    Mar 23, 2021 at 12:45


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