An accelerometer of the type in which a disk is mounted upon a vertical post. The biomaterials exhibit biological activity after patterning. The electrical connector allows the cover member to be opened and closed corresponding to the body member. The embodiment of the culture tray warrants uniform moistening of all existing plant spaces and ensures that even those plants receive enough water that are, for example, partly covered by large leaves of adjacent plants, since the water draining down the elevations flows into each individual plant space.