Xiaofan, I use calculator-style LED displays, just 1 Australian dollar each Search for D04 here http://www.oatleyelectronics.com/ Pictures of mine. They're multiplexed just like any other display http://home.clear.net.nz/pages/joecolquitt/led1.jpg End-on, showing lenses http://home.clear.net.nz/pages/joecolquitt/led2.jpg If '7120' is a date code ......... wow ! http://home.clear.net.nz/pages/joecolquitt/led3.jpg -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist