Nowadays, in order to fulfill the demands of the current market conditions, the synergy between products and services is becoming very important -- Every day, people are using more technologies being less aware of it -- Ubiquitous Technologies (UT) allows the synergy between this new products and its users in a more effective way: being unobtrusive and having information widely available, reliable and relevant -- These technologies are a useful approach for the design and development of technical systems for mission-critical applications -- Located in a near future where phenomena as global warming and climate change raise the question of how food will be produced -- This work presents a ubiquitous monitoring system for greenhouses -- The system is composed by a modular hardware platform and uses Expert Systems (ES) to support the decision making process during the data processing -- The system was designed, built and tested using two different platforms in order to validate its usability for Ubiquitous Systems (US) -- A step by step process is proposed for the data acquisition, formalization and inclusion of expert knowledge into a U
