Shares in AIM-listed Photonstar lost a third of their value on Wednesday after warning on revenues and predicting a loss for the year.The group explained that sales of fixed white lighting products for the year had been lower than previously indicated and that several large lighting domestic and export contracts had been delayed into 2015.The light engines business also experienced a slow-down in sales with pressure on margins.As such, the board has now decided to commit no further development resources to this area of business and focus its efforts on expanding the Halcyon product range more rapidly."The board believes this strategy will offer a greater return on investment in 2015," it said.The latest problems come on the back of previously reported weather-related delays in the new build market, which resulted in some revenue slipping into the second half of the year.As part of its reinforced focus on the Halcyon product range, the group has appointed David McTurk as interim chief operating officer, who was most recently the chief executive of OWL Institution, a manufacturer of wireless and cloud based energy monitoring and heating control systems.Group chief executive James McKenzie said McTurk has "a strong background and track record in the development of connected products that will contribute significantly to our future growth". "We believe that the intelligent, energy saving and data-centric applications of our unique Halcyon technology offer the potential to address a broad range of significant future business opportunities and markets," he added.