When a circuit board layout is created from the schematic shown in Figure 9-1, a small circuit board is possible. The accuracy of a temperature and relative humidity measurement is dependent upon the sensor accuracy and the setup of the sensing system. Since the HDC302x measures relative humidity and temperature in its immediate environment, it is critical that the local conditions at the sensor match the ambient environment. Use one or more openings in the physical cover of the thermostat to obtain a good airflow even in static conditions. Refer to the layout (Figure 11-1) for a PCB layout which minimizes the thermal mass of the PCB in the region of the HDC302x, which can improve measurement response time and accuracy.