Abstract: A liquid flow rate detector and controller having a microprocessor that senses the rate of drops falling in a monitoring balloon on a fluid tube. A light emitter/detector diode pair detects drops as they fall in the balloon, which are timed by the microprocessor. The device has first and second switches manufactured in a single small unit made of thin laminates. Each switch comprises an electrode and a contact point, mutually facing across a gap in the layers. The lamina on at least one side of each switch is elastic. External force flexes the elastic layer, causing it to bend across the gap, causing the electrode and the contact point to touch. A fluid tube is inserted in a narrow channel between the first switch and a movable wedge. A stepper motor under control of the microprocessor moves the wedge to press the fluid tube against the first switch until the contacts close. This indicates that the fluid tube is completely flattened and closed.