U3 IO Shield is the board that can be plugged on the neat of ODROID-U3 via tiny 8 pin IO connector. You can have 36 IO ports of GPIO/PWM/ADC. The shape and dimension are exactly same as ODROID-U3. It comes with 12pcs of PCB spacers for easier and solid stacking assembly.
Best low-cost environmental sensing solution with BME280 and Si1132 on one board. The combination of the BME280 sensor and the Si1132 sensor enables measuring temperature, barometric pressure and humidity, UV Index and ambient light at once. 6pin header socket is already soldered. You can simply plug it on to the right connector.
RTC backup battery Lithium primary battery to back up the RTC on XU board. This battery can keep the RTC running up to 5 years without external power supply.