Sir, I had published an article in 2013 which detailed about sourcing data from Tweets. Here is link to the article http://sapexperts.wispubs.com/BI/Articles/Analyze-Customer-Sentiment-by-Sourcing-Tweets-Using-SAP-BODS?id=28055AD319A3448D956229DCA8109462
I am sure that technology has evolved since then and therefore there could be easier/ simpler options to source data and apply algorithms to derive Sentiments from the text (tweets)