Thanks to the extension connector, you can buy or design yourself a lot of add-on boards and peripherals. It’s a standard 2.54mm header, so it is also compatible with standard electronic prototyping platforms. In addition to the power rail there are 4 digitals inputs/outputs. You can choose between various mode : SPI protocol, I2C protocol + 2 GPIO, UART (Serial) protocol + 2 GPIO or 4 GPIO. This is the perfect things to bring interactive game design to live, or even crazy robots !