MER 2.0 — An Open-Hardware, Computer-Vision Lab Kit for Coupled-Oscillator Modeling in Lower-Division Linear Algebra
[DRAFT — pilot data section marked as forthcoming.] Anderson (2018) introduced the Make Eigenvalues Resonate (MER) project as a hands-on bridge from introductory linear algebra to vibrations analysis using a spring-coupled pair of pendula. Six years later, the project still depends on ad-hoc hardware and bespoke video analysis, which limits adoption outside Anderson's own classroom. We present MER 2.0: a fully reproducible, sub-$80 hardware bill of materials, an open-source OpenCV tracking pipeline that runs from any phone-recorded video, and a three-mass extension that lets students see — and verify by measurement — the eigenstructure of a system with multiple natural frequencies. A single-section pilot in Math 2BL at Foothill College is planned for spring 2026; pilot results (kit assembly, eigenvalue-vs-measurement agreement, and self-reported gains against Anderson's five anti-racist learner-centered objectives) will be reported in the full draft. We argue that low-cost reproducible hardware is the binding constraint on the spread of modeling-rich linear algebra labs, and offer MER 2.0 as a template for hardening other projects in the Math 2BL family.
- RQ1Can a sub-$80 BOM reproduce — within tolerable error — the same eigenvalue-vs-measurement comparisons that the original MER apparatus achieved?
- RQ2Does adding a third mass (and therefore a third visible eigenmode) qualitatively improve students' intuition that eigenvalues are physical things, not just symbols?
- RQ3What is the smallest hardware + software footprint that lets a community-college student verify their own model without a teacher present?
Hybrid (engineering + classroom). (i) Design and bench-test a v2 hardware kit. (ii) Build the OpenCV pipeline as a single Python script + a Colab notebook with zero local install. (iii) Derive the 2-mass and 3-mass equations of motion, diagonalize, and validate predictions against tracked motion. (iv) Run a single-section pilot in Math 2BL Spring 2026 with pre/post survey on Anderson's learner-centered objectives. (v) Publish kit, code, and curriculum under CC-BY + MIT.
Eigenvalue/eigenvector decomposition; small-angle linearization; coupled ODEs; OpenCV (BGS, optical flow, or color-blob tracking); basic statistics (RMSE, paired t-test); LaTeX.
- Wk 1–2Reread Anderson (2018) end-to-end. Recreate the original 2-mass derivation by hand. Annotate every figure.
- Wk 3–4Bench prototype: dowel + fishing line + neoprene springs + 3D-printed mass holders. Phone-camera recording on a tripod against a known scale. Cost ledger updated.
- Wk 5–6OpenCV pipeline. Single Python script that ingests an .mp4 and outputs CSV of (t, x1, x2, x3) plus a fitted-frequency JSON. Colab port.
- Wk 7Derive 3-mass case symbolically (SymPy). Diagonalize. Compare to measured frequencies. Iterate hardware until RMSE < 5%.
- Wk 8Lock the BOM. Photograph the kit. Write the curriculum sheet (student-facing 8-step modeling worksheet).
- Wk 9Pilot in one Math 2BL section. Pre/post survey. Collect at least one student-built kit photo per group.
- Wk 10Draft v1 of paper following PRIMUS structure (Motivation → Theory → Activity → Student Work → Reflection).
- Wk 11Mentor-review pass with Jeff. Revisions.
- Wk 12Submit to PRIMUS.
- Hardware drift. Cheap springs have nonlinear and temperature-sensitive constants — RMSE may explode. Mitigation: characterize each spring before assembly; report uncertainty bounds.
- Tracking failures. Phone video at 30 fps may alias the higher modes. Mitigation: 60 fps minimum; verify Nyquist at design time.
- IRB / consent. Pre/post survey of students requires Foothill IRB exemption. Start the paperwork in Wk 1, not Wk 8.
- Scope creep. Resist the urge to also rewrite the LANA paper. Three-mass case is the ceiling.
Mediocre: “Here is a cheaper version of MER, and students liked it.”
Publishable: “Here is the smallest verifiable footprint at which a student can check eigenvalue theory against the physical world without a teacher; here is the data; here is the BOM you can buy from Amazon today.”
Three-mass system phase-space animation overlaid with predicted vs. measured trajectories — same plot, different colors, RMSE annotated.
- · Hardware BOM v0
- · OpenCV pipeline v0
- · Wk 1 reread
- · IRB exemption form
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