Showing posts from January, 2019

Controlling lots of OLED displays with a few GPIO pins

On my mission to learn as much as possible about "IoT" and all of the accessories/sensors/displays that are popular in the market, I came across some projects which were using multiple OLED displays to form dashboards and control panels. I hadn't thought about this usage, but it makes sense considering how inexpensive (and small) they are. The challenge presented with this idea is that the inexpensive hobby parts either have a fixed I2C address (usually 0x3C) or a single jumper to select an alternate address (usually 0x3D).

The photo above shows a collection of readily available and inexpensive I2C OLED displays. The top 3 have a single address selection jumper. The bottom 2 don't show any specific jumper for changing the address, although one or more of the SMD resistors might control it. Either way, most hobbyists are not prepared to work with tiny, surface mount resistors.

If they all are set to the same I2C address, then in order to get more than 1 display workin…