I have many ideas to use these nice little 128X32 oled screens. Or even the 128X64. I wanted to use a single cheap UNO and the Pro Mini was about the smallest and most practical. The problem with using a single I2C port, these oleds only use a single address, 0x3C. I decided to attempt to use 9 I/O pins to act as the SDA pin for each oled and then use a single I/O pin to act as the SCL ouput for all 9 ports. This obviously reqired a software I2C implementation. I experimented with a lot of libraries and most would overwhelm the RAM of the Pro mini and did not even download. The one I found worked the best was U8X8lib.h This library allows you to assign pins to the SDA anc SCL pins from any port and draw or write text to the oled. I created 3 sets of 3 oled arrays. Making a single 9 oled array was for some reason breaking down the operation. It would compile but not operate. My first test was to power all 9 and display a number for each oled.