The real-world implementation of a just theoretically elaborated idea is sometimes cumbersome, often a couple of obstacles have to be overcome. That?s likewise in the area of Wireless Sensor Networks (WSN), but complicated by some further restrictions, e.g. little memory or low power consumption. One well-known and often required application within WSN is the geographical localization of several sensor nodes. That?s why this paper deals with some problems arising during the development of a WSN using the time difference of arrival (TDoA) of ultrasound and radio signals for positioning. Its focus is on handling of microcontroller difficulties like little memory, low computational power or low energy consumption as well as hardware driven failures like inaccurate measurements or node failures.