--> There are some *cheap* way of measuring 635nm and 532nm laser beam power? <-- You can buy a calibrated photodiode from Sam Wasserman (Sam's Laser FAQ) for a couple of bucks. Neil -- http://www.pixpopuli.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist