A bit more on the goal and constraints, from the 2023 Science Olympiad "Detector Building" project (for grades 9 to 12) rules:
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The goal is a "mass/force-sensing device" that will measure and display the "voltage and actual masses" of "solid samples ranging from 30 to 1,000 grams" to the "nearest 0.1 gram."
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Prohibited: the use of load cells, "printed circuit boards (except digital display boards), and integrated circuit daughter boards." So using an HX711 breakout would be a violation.
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Allowed "FSRs, strain gauges, capacitors, resistors, DIP ICs, and surface-mount adapter boards."
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"deliverables" include: a "scatter plot" showing mass vs voltage, a table showing "raw sensor readings (voltage, time, etc.) vs mass, and if multiple fixed resistors are tried, include the data for all trials."
The rules appear to conflate mass and weight or force.
The mention of "time" suggests a possible spring/mass setup. The mention of trying multiple fixed resistors anticipates the use of an FSR.
A different post on the same project: