The in-situ detection of air bubbles in fluid transport lines is a significant problem in both industry and medicine. To address this challenge, we designed a microfluidic device embedded with a piezoresistive film made by evaporating metallic nanoislands on graphene. The piezoresistive film senses bubbles by measuring the change in the elastohydrodynamic deformation of the channel wall. By embedding the piezoresistive film a few microns away from the channel, we create a device that is non-contact, resistant to extreme environments (acidic, basic, turgid, etc.), and doesn’t interfere mechanically or electrically with the sample fluid. In addition to the advantages in other non-contact detectors, our sensor allows us to create a low power device with a high signal to noise ratio. We are able to detect bubbles in a fluid and report these events to a smartphone wirelessly through our battery-powered device.