Bluetooth-Low-Energy Telemetry Packet Loss in Student-Built Engineering Education Sensor Nodes: A Controlled Attenuation Evaluation Linking Antenna Detuning to Data-Continuity Reliability Bounds

Student-built sensor nodes are widely used in engineering education laboratories, yet their telemetry reliability is rarely characterised with the same rigour demanded of commercial hardware. The model treats the antenna as a resonant element whose detuning, caused by hand placement, enclosure proximity and ground-plane truncation, shifts the reflection coefficient and reduces the effective link margin. A before-after-control-impact (BACIP) design is specified to evaluate the model's operating characteristics under a declared variance structure: between-cluster standard deviation of 6.0, residual standard deviation of 4.5, and intraclass correlation of 0.64. Power was estimated across 2000 design cells for cluster counts of 8, 16, 24 and 32 and effect sizes of 3, 5 and 8 percentage points. The analysis indicates that 56 clusters are required to detect a 5-percentage-point effect at 80% power. The contribution is a bounded, testable specification of the reliability envelope within which student-built BLE nodes can be expected to deliver continuous telemetry, together with the design parameters that a laboratory evaluation must satisfy to detect departures from that envelope.