micro:bit and MMA7361 accelerometer example

The MMA7361L is a low power, low profile capacitive micromachined accelerometer featuring signal conditioning, a 1-pole low pass filter, temperature compensation, self test, 0g-Detect which detects linear freefall, and g-Select which allows for the selection between 2 sensitivities. Zero-g offset and sensitivity are factory set and require no external devices. The MMA7361L includes a Sleep Mode that makes it ideal for handheld battery powered electronics.

Features
• 3mm x 5mm x 1.0mm LGA-14 Package
• Low Current Consumption: 400 μA
• Sleep Mode: 3 μA
• Low Voltage Operation: 2.2 V – 3.6 V
• High Sensitivity (800 mV/g @ 1.5g)
• Selectable Sensitivity (±1.5g, ±6g)
• Fast Turn On Time (0.5 ms Enable Response Time)
• Self Test for Freefall Detect Diagnosis
• 0g-Detect for Freefall Protection
• Signal Conditioning with Low Pass Filter
• Robust Design, High Shocks Survivability
• RoHS Compliant
• Environmentally Preferred Product
• Low Cost

Typical Applications
• 3D Gaming: Tilt and Motion Sensing, Event Recorder
• HDD MP3 Player: Freefall Detection
• Laptop PC: Freefall Detection, Anti-Theft
• Cell Phone: Image Stability, Text Scroll, Motion Dialing, E-Compass
• Pedometer: Motion Sensing
• PDA: Text Scroll
• Navigation and Dead Reckoning: E-Compass Tilt Compensation
• Robotics: Motion Sensing

Schematic and connection

 

microbit and mma7361
microbit and mma7361

 

Code

 

void setup() 
{ 
  Serial.begin(9600); // 9600 bps
  pinMode(3, OUTPUT);
  digitalWrite(3, HIGH);
}
 
void loop() 
{
  int x,y,z;
  x=analogRead(0);
  y=analogRead(1);
  z=analogRead(2);
  Serial.print("x= ");
  Serial.print(x ,DEC);
  Serial.print(',');
  Serial.print("y= ");
  Serial.print(y ,DEC);
  Serial.print(',');
  Serial.print("z= ");
  Serial.println(z ,DEC);
  delay(250);
}

 

Output

Open the serial monitor and move the sensor around, you should see soemthing like this

X = 86
Y = 82
Z = 656
X = 68
Y = 80
Z = 640
X = 76
Y = 80
Z = 657
X = 422
Y = 96
Z = 653
X = 354
Y = 80
Z = 656
X = 1573
Y = 216
Z = 857

 

Links

http://www.nxp.com/files/sensors/doc/data_sheet/MMA7361L.pdf

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