acquiring data from an adxl335 accelerometer
Post on 12-Feb-2016
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DIGIKEY DKSB1002A Evaluation Board3-axis accelerometer
Arduino Unomicrocontroller board
Acquiring Data from anADXL335 Accelerometer
living with the lab
• DKSB1002A is a prototyping board purchased for $20 from Digikey • Screw holes for mounting board onto “object of interest”• Board is ~ 20mm square• ADXL335 3-axis accelerometer chip
• 3-axis• ±3g
• COM - ground• VSS - power (we will provide 5V)• X - acceleration in x-direction• Y - acceleration in y-
direction• Z - acceleration in z-direction
DKSB1002A Evaluation Board and ADXL335 Accelerometer
xy
z
this small chip is the ADXL335 accelerometer(this is an older model . . . they are even smaller now)
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the DKSB1002A is a board used to evaluate the accelerometer; if you were putting an accelerometer in a device like a cell phone, you would only use the ADXL335 chip (and maybe some capacitors)
COM - groundVSS - power (we will provide 5V)X - acceleration in x-directionY - acceleration in y-directionZ - acceleration in z-direction
Implementing a 3-axis Accelerometer: Wiring to Arduino
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void setup(){ Serial.begin(9600);}
void loop(){ int xaccel = analogRead(0); int yaccel = analogRead(1); int zaccel = analogRead(2); unsigned long timevar = millis(); Serial.print(timevar); Serial.print(" "); Serial.print(xaccel); Serial.print(" "); Serial.print(yaccel); Serial.print(" "); Serial.println(zaccel);}
Programming
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associates a time witheach set of accelerations
Calibration
xy
z
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Angle Measurement
xy
z
1g (perceived vertical acceleration)
ax
x
x
+x
θx = asin(ax/g)
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Example Application
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void setup(){Serial.begin(9600); }
void loop(){ int xaccel = analogRead(0); int freq = 1500+xaccel*2; tone(7,freq);
Serial.print(xaccel); Serial.print(" "); Serial.println(freq);}
The piezospeaker below outputs a frequency that varies with the acceleration in the x-direction. The equation for computing the frequency is chosen so that the device makes an audible noise that varies when rotating or shaking the device.
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