Using multiple breakouts


I’m new to the world of using the GPIO headers on a raspberry pi, and have a question about using multiple breakouts. I notice when looking through the breakout boards, a lot of them say they’re designed for use with pins 1, 3, 5, 6, 9. I’m specifically interested in using the ICM20948 and ADS1015 breakouts together. I see the 3v3, GPIO and ground pattern is repeated on pins 17-25. Would it be possible to move one of the breakouts to this other set of pins, or do I need to buy something like the mini breakout garden?

The 1, 3, 5, 6, 9 pattern was picked because GPIO 3 is SDA and GPIO 5 is SCL. Those are the two pins used for i2c, and i2c is a shared bus. You can connect multiple i2c devices to those two pins, and as long as no two devices have the same i2c address, everything will work just fine. It was just luck that 3.3v and ground are close buy, and GPIO 4 is an extra bonus pin for adding another function.
The Breakout Garden i2c sockets just daisy chain those pins from socket to socket.
You can connect multiple i2c breakouts to those GPIO pins any number of ways.
I’ve done it with a proto hat and some headers and jumper wires.

The green and yellow wires are SDA and SCL, black is ground and red 3.3v.

1 Like

The two breakouts you listed both use i2c, and have different i2c addresses. The only thing that may be an issue is if they both use the Int pin. If your not using the breakout garden hat you could wire one of the breakouts Int pin to a different GPIO pin and edit the python file to match the one you use. Assuming its needed. I don’t think they are always used. I would just leave the Int pin unconnected and see if everything works. If one breakout won’t work connect its Int pin to GPIO 4 and see if that fixes things.

1 Like

Ok, I’ll try daisy chaining them using a breadboard. Thanks very much!

I like using the Proto Hats because they have a 40 pin header that plugs right into the Pi. And all the GPIO are brought out and labeled for easy connection. And if you use a stacking header you can plug a hat in on top of them. There is a Pi A+ under the one in my picture, and a Sense Hat gets plugged in on top.