Smart Petri: Automating Lab Work One Dish at a Time

This report outlines the development of an automated Petri dish handling system—Smart Petri—designed to streamline bacterial culturing workflows in veterinary diagnostic laboratories. In partnership with Hamilton Company, a global leader in laboratory automation, the ME310 team at Stanford University explored ways to reduce technician workload, increase operational efficiency, and improve diagnostic reliability in settings traditionally underserved by automation. The veterinary diagnostics industry faces distinct challenges compared to human biolabs, including smaller sample volumes, higher sample variability, limited workspace, and frequent manual interventions. These constraints are exacerbated by rising labor costs and technician shortages, which have created a pressing need for affordable, compact, and modular automation solutions. In response, Smart Petri was conceptualized as a semi-automated, user-centered system to handle the most tedious and error-prone tasks in the Petri dish workflow: unlidding, labeling, handling, and restacking. Our design process followed an iterative prototyping approach grounded in extensive needfinding, benchmarking, and user testing. Initial prototypes, including the "Dark Horse" and "Funky" iterations, validated critical functional goals—such as reducing dish handling time by up to 28.1%—while surfacing mechanical challenges like lid removal tolerances and system jamming. These insights guided the development of our current Functional Prototype, which integrates four key modules: Petri dish cartridges, a rotating dish carousel, an unlidding station, and a thermal inkjet labeler. The system is controlled via a state-machine architecture implemented on an Arduino-based platform. User feedback and performance testing informed both mechanical and usability improvements, such as reducing cantilevered components, refining lid removal methods, and planning for sensor integration to enable closed-loop operation. The modular architecture of the system ensures adaptability to various lab environments and provides a foundation for adding future capabilities like automated streaking and imaging. Ultimately, Smart Petri offers a scalable solution to modernize veterinary bacterial culturing. By addressing real-world constraints and prioritizing user experience, the system contributes to Hamilton’s goal of redefining animal-centric lab automation while laying the groundwork for future deployment in agricultural and food safety contexts.