SUNSETSEJONG UNIVERSITY
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P-05 · Supporting

Intellichair

SupportingPrototypeEmbeddedRobotics

Verified summary

Smart-chair sensing prototype estimating seated balance and posture-related signals from load cells and an IMU.

Problem or experiment question

Can four load cells and an IMU provide useful seated symmetry and posture-related feedback on embedded hardware?

What was actually built

  • Four load cells with HX711 interfaces
  • Left/right normalization, Symmetry Index, and Center of Pressure calculation
  • BMI270/BMM150 IMU accelerometer-angle calculation
  • Buzzer feedback and BLE service/characteristic concept in firmware

Architecture or workflow

  • Sensor layer: load cells and IMU
  • Signal layer: normalization and symmetry metrics
  • Feedback layer: buzzer and proposed BLE notifications

Important technical decisions

  • Symmetry Index simplifies bilateral load comparison
  • IMU augments load-only sensing with orientation context
  • Buzzer provides immediate local feedback without a companion app requirement
Intellichair smart-chair sensing prototype using four load cells with HX711 interfaces and a BMI270 BMM150 inertial unit to compute symmetry index, center of pressure, and accelerometer angles, with buzzer feedback and a proposed BLE service path.SIG-ICH · POSTURE SENSINGSENSORSLoad cells ×4HX711IMUBMI270 · BMM150Normalizationleft / rightMETRICSSymmetry Indexbalance ratioCenter of Pressureseat mapAccel anglestilt estimateFEEDBACKBuzzerthresholdBLE serviceproposed GATTOUTPUTPosture signalsprototype metricsfirmware pathBLE incomplete
System diagram

Public status

PrototypeImplementedExperimentalIncomplete
Arduino
HX711
Load cells
BMI270
BLE

Known limitations

  • BLE initialization, advertising, and characteristic updates appear incomplete
  • Division-by-zero handling may be missing when total load is zero
  • Center of Pressure may be calculated but not meaningfully used
  • No clinical validation; health-monitoring claims exceed implementation

Repositories

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