Mechanical Engineering
Graduate Seminar
NOTICE OF SEMINAR PRESENTATION
CANDIDATE: Abdulrahman Altabbaa
DEGREE SOUGHT: MASc
DATE: 10/9/2026
TIME: 11:30am
PLACE: Room 1101 CEI
TITLE: Virtual Temperature Sensor for Peltier-Based Systems: Non-Invasive Droplet Temperature Estimation
Abstract
Digital microfluidic (DMF) lab-on-a-chip devices move and process individual droplets on an electrode array, which makes them attractive for automated, portable biochemical analysis. Assays such as glucose detection rely on enzymatic reactions whose rates depend on temperature, so the droplet must be held at a precise temperature for reliable results. Measuring that temperature directly is difficult. A sensor at the droplet surface obstructs droplet motion, damages the hydrophobic coating that DMF actuation depends on, and complicates fabrication. A virtual temperature sensor, which estimates the droplet temperature from measurements taken away from the droplet, avoids these problems.
This work develops such a virtual sensor for a Peltier-based DMF platform. A Peltier module beneath the PCB heats and cools the droplet, and the only physical sensor is a thermocouple between the Peltier and its heatsink. An analytical, layer-by-layer model combines this bottom temperature with the Peltier's live current and voltage to predict the Peltier's top-surface temperature. It then carries that prediction through the PCB using its thermal resistance and capacitance to estimate the droplet temperature. Compared with placing sensors at the droplet, this approach leaves the DMF surface untouched, needs no extra fabrication steps, and uses a single low-cost sensor that stays hidden under the Peltier. Because the model is built from physical parameters, changes in PCB thickness or heatsink, or Peltier only require updated parameters. The result is a low-cost method to reliable droplet temperature monitoring, which supports more accurate and repeatable assays in portable DMF biochemical analysis devices.