This paper presents the development of a wireless flow transmitter using rotameter and operational amplifier based signal conditioning circuit. The rotameter is a linear gravity based flow measuring device. It consists of a display unit which directly displays the flow rate. For industrial applications a new circuitry is required to transmit the measured flow rate to the control unit at remote areas. A ferromagnetic wire attached to the float of rotameter acts as a core of an inductance pickup coil constitutes the flow sensor. The self-inductance of the coil changes according to the change in flow rate. An operational amplifier based circuit is used for the measurement of self-inductance. The voltage corresponding to the flow rate is finally converted into 4-20 mA current. A wireless readout is provided using a microcontroller unit and a Bluetooth module. The results show a linear relation between the variation of self-inductance of a pickup coil as well as transmitter output with respect to flow rate. The theoretical equations and the simulation results are added in this paper.