VILNIUS, July 12 (Reuters) - The mayor of Vilnius plans to

install a huge screen on the town hall to broadcast a real-time

"happiness barometer" that will monitor the mood of the

Lithuanian capital.

The giant display will monitor the level of happiness among

the city's 520,000 residents by showing a number on the scale of

one to 10 that reflects tabulated votes sent in by locals from

their mobile phones and computers.

The system is already set up and on televisions in the lobby

of the municipal office.

"This barometer is a great tool for politicians. If we take

a decision and see a sharp fall in the mood of the city, then we

know we have done something horribly wrong," mayor Arturas

Zuokas said.

This week the barometer has been hovering around six to

seven points.

A 2011 poll of global happiness by WIN Association, a

network of pollsters, found Lithuania, hit hard by the 2008-2009

financial crisis, among the unhappiest countries of 58 surveyed.

Only Serbia, Palestine, Egypt and Romania fared worse.

(Reporting by Andrius Sytas; Writing by Alistair Scrutton,

editing by Paul Casciato)