Table 13.
Typical Constraints of Sensors Used in Wearable Gait Monitors.
| Parameter (Sensor Type) | Example | Power [mW] 1 | Cost [USD] 4 | Size [cm] 5 |
Weight [g] |
|---|---|---|---|---|---|
| Bending/Vibration (PVDF Strips) |
TE Connectivity LDT0 [69] used in [19] | NA | $2.69 | 2.5 × 1.3 | NA |
| Angular rate, orientation (gyroscope) | Analog Devices ADXRS290 similar to ADXRS150 [70] used in [19] | 39 (0.4) 2 |
$16.06 | 0.6 × 0.4 | NA |
| Acceleration, angular rate, orientation (IMU) | XSens MTi-1 [71] | 45 | $139 | 1.2 × 1.2 | 0.66 |
| Distance (Hall effect) |
Allegro 139X [68] replacement for sensors used here | 9.6 (0.08) 2 |
$1.20 | 0.8 × 0.3 | 0.014 |
| Distance (Infrared IR) |
Sharp GP2YOA41SKOF [72] used in [61] | 60 | $9.93 | 4.4 × 1.9 | 3.5 |
| Distance (Ultrasonic) | URM07 [73] | 25 (0.07) 2 |
$5.59 | 2.7 × 2.7 | 4.2 |
| Force/Pressure (Force-Sensitive Resistor) | FSR-400 [74] used in [19] | 2.5 3 | $4.40 | 4.0 × 4.0 | NA |
| Linear Acceleration (accelerometer) |
Analog Devices ADXL202E [75] used in [19] | 3.0 | $19.72 | 0.7 × 0.7 | 5 |
| Object Presence (electric field sensors) |
Motorola MC33794DH [71] used in [19] | 98 | $24 (est) | 1.6 × 1.1 | NA |
1 Power consumption provided at typical supply voltages (as specified in datasheet). 2 In measurement (sleep) or measurement (non-actuated) mode at typical supply voltage. 3 Based on 10 k measurement resistance when bent and a basic measurement circuit. 4 Cost estimated at quantities of 100 units. 5 Thickness was either not specified or is small compared to remaining two dimensions; NA: not available.