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# Grove-Single Axis Analog Gyro‏‎

The Grove – Signal Axis Analog Gyro is based on an angular velocity sensor (Murata-ENC-03R) that uses the phenomenon of Coriolis force. It can only measure the X-axis angular velocity, which is different from other 3-Axis gyro, but with a higher speed. It can be used for the position control and attitude control like the self-balanced 2WD.

Model:SEN05091P

## Feature¶

• Input Voltage: 3.3V/5V

• Standard Grove Interface

• Light Weight

• High Speed

• Measure X-axis Angular Velocity

## Demonstration¶

### With Arduino¶

The module detects one-axis rotation with analog signal. High-pass filter and low-pass filter circuit are applied to reduce the temperature drift and suppress the output noise. Before the measurement of the angular velocity, a reference value(the sensor output at Angular Velocity=0) is required. This value is 1.35V in default. But in order to get more accurate reference values, before the measurement,a calibration is necessary. In this calibration, the output voltage when angular velocity =0 been sampled 200 times, and then the average of these data will be treated as the reference value.

1.Connect it to A0 port of Grove - Base Shield, of cause any pin of the analog pins would be OK.

2.Plug the Grove - Base Shield into Arduino/Seeeduino and connect them to PC using a USB cable.



int sensorPin = A0; // select the input pin for the sensor

float reference_Value=0;

int sensorValue = 0; // variable to store the value coming from the sensor

void setup()
{

int i;
float sum=0;
pinMode(sensorPin, INPUT);
Serial.begin(9600);
Serial.println("Please do not rotate it before calibrate!");
Serial.println("Get the reference value:");

for(i=0;i<1000;i++)
{
// read the value from the sensor:
sum += sensorValue;
delay(5);
}
reference_Value = sum/1000.0;
Serial.println(reference_Value);
Serial.println("Now you can begin your test!");
}

void loop()
{
double angularVelocity;
angularVelocity =((double)(sensorValue-reference_Value)*4930.0)/1023.0/0.67; //get the angular velocity
Serial.print(angularVelocity);
Serial.println("deg/s");
Serial.println(" ");
delay(10);
}


4.Now, it is time to the calibration.Put the sensor on your desk horizontally， and then press the Reset button on the Seeeduino, and then Open the serial tool:

5.As you see the "Now you can begin your test", that means the calibration done. You can use the sensor now. Rotating direction can reference the following picture:

### With Raspberry Pi¶

1.You should have got a raspberry pi and a grovepi or grovepi+.

2.You should have completed configuring the development enviroment, otherwise follow here.

3.Connection - Plug the sensor to grovepi socket A0 by using a grove cable.

4.Navigate to the demos' directory:

cd yourpath/GrovePi/Software/Python/ - To see the code

nano grovesingleaxisanaloggyro.py # "Ctrl+x" to exit #

import time
import grovepi

#Connect the Grove Single Axis Analog Gyro to analog port A0
#SIG,NC,VCC,GND
sensor = 0

grovepi.pinMode(sensor,"INPUT")

#calibration
print "calibrating..."

sum = 0

errors = 0

for x in range(0, 100):

try:
#Get sensor value
sum += v
#time.sleep(.05)
except IOError:
print "Error"
errors += 1

if errors == 100:

print "unable to calibrate"

raise SystemExit

reference_value = sum / (100 - errors)

print "finished calibrating"
print "reference_value =", reference_value

while True:
try:
#Get sensor value

#Calculate angular velocity (deg/s)
velocity = ((float)(sensor_value - reference_value) * 4930.0) / 1023.0 / 0.67

print "sensor_value =", sensor_value, " velocity =", velocity
time.sleep(.5)

except IOError:
print "Error"


5.Run the demo.

sudo python grovesingleaxisanaloggyro.py`

## Resource¶

[Datasheet] File Signal Axis Analog Gyro datasheet

[Code] Demo code on github

## Tech Support¶

Please submit any technical issue into our forum or drop mail to techsupport@seeed.cc.