DEMOAPEXSENSOR Freescale Semiconductor, DEMOAPEXSENSOR Datasheet - Page 19

• Manufacturer Part Number: DEMOAPEXSENSOR
• Description: BOARD DESIGN ALTITUDE PRESSURE
• Manufacturer: Freescale Semiconductor

Specifications of DEMOAPEXSENSOR

• Sensor Type: Accelerometer, Pressure, Water Level, Altimeter/Barometer
• Sensing Range: Multiple Ranges
• Interface: I²C, SPI, Analog
• Sensitivity: Multiple
• Voltage - Supply: 10 V
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: MPX2102, MPXV5004G, MPL115A2, MMA7361L
• Acceleration: 6 g
• Sensing Axis: Triple Axis
• Output Type: Digital
• Interface Type: I2C, SPI
• Operating Voltage: 16 V
• Operating Current: 10 mA
• Leaded Process Compatible: Yes
• Peak Reflow Compatible (260 C): Yes
• Rohs Compliant: Yes
• Silicon Manufacturer: Freescale
• Silicon Core Number: MPXM2102A, MPXV5004G, MPL115A2, MMA7361L
• Kit Application Type: Sensing - Sampling Kit / Related Components
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: MPL115A, MPXM102A, MPXV5004G

Inertial MMA7361L
implements the tilt function of the accelerometer and Freefall detection. The
function.
TILT ANGLE ON THE DEMOAPEXSENSOR
Note: MMA7361 was set to a g-level of 1.5 g.
FREEFALL DETECT ON THE DEMOAPEXSENSOR
given as an output on the MMA7361L as the 0g-Detect pin. ‘1’ or logic high is the output for a detected Freefall. Note that this is
also for Freefall in a linear fashion such that the board is not spinning or in rotation as it falls. The DEMOAPEXSENSOR emits a
buzzer noise and a flashing red LED as the Freefall detect occurs.
Sensors
Freescale Semiconductor
The DEMOAPEXSENSOR has a quick implementation of the 3 axis selectable low-g accelerometer. Notably the demo board
The ADC counts are converted to tilt angles using the equation below:
Freefall detect is the situation where all three axes of the inertial sensor converge towards the offset or ‘0g’ range. This is also
Where:
Offset voltage is typically 1.65V @ 3.3V biasing supply
Vout = Analog output of accelerometer
Voff = Offset voltage of accelerometer
V/g = Sensitivity
1.0g = Earth’s gravity
θ = Tilt Angle
Vout
=
Voff
+
⎛
⎝
ΔV
------- - 1.0g Sinθ
Δg
⋅
⋅
Quick Start Guide
⎞
⎠
(eq. 4)
shows the modes to select either
AN3956
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