Recently, I have been trying to build a project where I need to connect an ev3 to a raspberry pi. I have decided doing it by i2c after reading (and successfully replicating) an article about connecting an ev3 to arduino by i2c https://www.dexterindustries.com/howto/connecting-ev3-arduino/.  However, after setting it up with raspberry pi, I realized a huge problem that I am facing, both of these devices acted as masters and I could not get them to connect to each other.

So, I decided to use an Arduino between those two which transports the data that it receives to the other device, which I couldn't get working. I have no idea how to get it working anyways, it was just a hopeless try.

Is such a project possible or should I just give up? If I should, what type of communication do you suggest that I use?

If you know any way of putting the Raspberry Pi into the slave mode, I would really appreciate if you share it.

  • I'm using TCP over USB to connect to my EV3. It allows me to ssh into EV3, it's a level I feel more comfortable with than i2c. Jun 11, 2018 at 9:08
  • What exactly is an ev3 Jun 11, 2018 at 17:10
  • What exactly did you "successfully replicate"? Jun 21, 2018 at 7:00
  • Lego Mindstorms EV3.
    – NomadMaker
    Feb 19, 2020 at 5:04

1 Answer 1


pigpio has limited support for the Pi to act as an I2C slave.

See http://abyz.me.uk/rpi/pigpio/python.html#bsc_i2c

That example is Python.

Note that when acting as a slave device you need to use GPIO 18 (SDA) and GPIO 19 (SCL). You also need to fit external pull-ups to 3V3. For reference the ones on GPIO 2/3 are 1k8 pull-ups to 3V3.

If you look through the documentation you will see several examples in C, Python, and the command line (pigs).

It is what it is - that means you will have to work around its limitations or find another solution.

See my post for background information and a usage example.

  • Wow, thanks man, you literally saved my life, though I need to ask, can I connect 43 K to 4.7 V since that worked with arduino. Sorry for the noob question, I am quite new to electronics.
    – Fr1nge
    Jun 11, 2018 at 7:35
  • I do not know what you mean by 43 K to 4.7 V. Remember ALL the Pi GPIO are only tolerant to a voltage between 0 and 3.3V. Anything outside those limits risks damaging the GPIO and the Pi.
    – joan
    Jun 11, 2018 at 10:02

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