Still some problems

Yesterday we found out that the I2C expanders (PCF8574) could not source the LEDs of the LED matrix. We did some measurements and apparently the output ports of the PCF8574 IC's gave only 70µA as output current which is to low of the LEDs to light up. The LEDs need 20mA. As a solution we drew another PCB to place on top of our original PCB. This new PCB has an LED driver circuit with a transistor for each LED. Below you can see the new PCB.

We also have a problem with our program for the arduino, it seems that using the NFC card reader with SPI and the I/O expanders with I2C work perfect separately but if we combine the 2 programs, only the SPI works and the I2C doesn't work anymore then. We are still trying to find what causes this problem, maybe the arduino is not able to use SPI and I2C at the same time or maybe it's something else, we don't know but we hope we'll find it soon.