Westside Middle School students in Danbury are participating in a district wide Invention Convention.  100 6th graders and 30 7th graders set up their projects yesterday in advance of district wide judging at Western Connecticut State University tomorrow.  Elementary school students are competing today for a chance to move on to the state competition.  Winners will participate in the 33rd annual Connecticut Invention Convention in April at UConn.  The Danbury students will face children from more than 130 Connecticut schools.  Students have been working for weeks to come up with ideas on how to solve problems, put them into motion and tweak them to perfection.