Connecting to the Arduino Pro Mini A4 and A5 I2C Pins

A project log for Oneoffs

Small, quick, oneoff projects

parasquidparasquid 08/18/2020 at 18:400 Comments

I needed to use I2C on a project with an Arduino Pro Mini, but on this model the A4 and A5 pins are 0.5in shifted and so wouldn't easily fit on a bread board without some gymnastics. I found a good way to bring them out, but it's only useful if you don't need to bring out all of the pins of the mcu.

I used right angle pin connectors on the raw/gnd/rst/vcc side and long pin 19mm connectors facing upwards on pins A4 and A5. Then I bent them down and angled a bit to compensate for the shift.

Here it is comfortably sitting on a breadboard. You do lose access to the top (mostly digital) pins, but depending on the project it may be a sacrifice that's worth it.