A scanning Fabry Perot interferometer is made using a piezoelectric transducer tube (PZT) as a scanning element, and a photodiode as a detector. The paper gives the constructional details of the interferometer and also of the electronic circuit required for obtaining the scanning. The performance of the interferometer is tested by analysing with it, the output of a 633 nm He-Ne lasers operating in single, and two mode fashion. The linearity of the PZT tube movement as a function of applied voltage is also estimated.