I recently bought a Dissolved Oxygen Kit from Atlas Scientific.

First I followed the instruction on the website to connect the device to my Raspberry Pi. This is my final result.

I then followed this guide which shows how to enable the i2c display on the Raspberry Pi.

When I try to run the command sudo i2cdetect -y 1 it should displays the information about the i2c devices connected. However, nothing shows up for me. I tried using another Raspberry Pi, different wires, even another i2c device but it definitely can't detect it.

I run the command sudo nano /etc/modules and added those two lines:



I also try using lsmod | grep i2c to be sure that everything is loaded and it is.

What am I missing here?

  • Is that LED green or blue? If it's green then your unit is in UART mode.
    – joan
    Oct 7, 2016 at 15:40
  • It flashes green, then green and blue and loop. Oct 7, 2016 at 15:43
  • I thought it was meant to be steady blue if it was set in I2C mode?
    – joan
    Oct 7, 2016 at 15:46

2 Answers 2


If you are using recent software (last 6 months or so) you should be using device tree.

Add the line dtparam=i2c_arm=on to the file /boot/config.txt.

Remove the line i2c-bcm2708 from /etc/modules.



As joan pointed out, it was indeed in UART mode so it is normal I could not detect it. More info here.

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