 The PCA9548, an 8-channel multiplexer, you can use multiples of the same board that have a conflicting address on I squared C. I have a cutie pie plugged into the PCA9548, and then I have two of these Vemmel 7700 light sensors. There is no jumper for addresses. We just have one address to work with, so I've got two of them plugged in here. This is a little graph that's showing the light sensor reads from the two sensors. I've got one facing down and one facing up here. So now you'll see a big difference between these, and let's say my light comes around to the other side, and now it's pointing up at that bottom one. So now we can detect light in two directions with this really great light sensor. It is the PCA9548 multiplexer for I squared C.