Opro9 SmartDiaper is a flat wetness sensor for nappies and is connected via Bluetooth 4.0 with the parents’ smartphone. When the nappy is wet, the sensor sends a signal immediately. The corresponding SmartDiaper app, which can be linked to five such sensors, also indicates the degree of wetness and the temperature in the nappy and memorises how often a child wets it. Both the sensor and its soft silicone holder are easy to clean.