Raspberry Pi and L3GD20 sensor

The L3GD20 is a low-power three-axis angular rate sensor. It includes a sensing element and an IC interface capable of providing the measured angular rate to the external world through a digital interface (I2C/SPI).

The IC interface is manufactured using a CMOS process that allows a high level of integration to design a dedicated circuit which is trimmed to better match the sensing element characteristics. The L3GD20 has a full scale of ±250/±500/ ±2000 dps and is capable of measuring rates with a user-selectable bandwidth.

Features

Three selectable full scales (250/500/2000 dps)
I2 C/SPI digital output interface
16 bit-rate value data output
8-bit temperature data output
Two digital output lines (interrupt and data ready)
Integrated low- and high-pass filters with user-selectable bandwidth
Wide supply voltage: 2.4 V to 3.6 V
Low voltage-compatible IOs (1.8 V)
Embedded power-down and sleep mode
Embedded temperature sensor

Here is a schematic showing the module I had, the module has an on board 3.3v voltage regulator

Connection

A layout showing how to connect this to your Raspberry Pi

Code

Save this as L3GD20.py

[codesyntax lang=”python”]

import smbus
import time

bus = smbus.SMBus(1)

# L3GD20 address, 0x69
bus.write_byte_data(0x69, 0x20, 0x0F)
bus.write_byte_data(0x69, 0x23, 0x30)
time.sleep(0.5)

# Read X-Axis data
data0 = bus.read_byte_data(0x69, 0x28)
data1 = bus.read_byte_data(0x69, 0x29)

xGyro = data1 * 256 + data0
if xGyro > 32767 :
	xGyro -= 65536

# Read Y-Axis data
data0 = bus.read_byte_data(0x69, 0x2A)
data1 = bus.read_byte_data(0x69, 0x2B)

yGyro = data1 * 256 + data0
if yGyro > 32767 :
	yGyro -= 65536

# Read Z-Axis data
data0 = bus.read_byte_data(0x69, 0x2C)
data1 = bus.read_byte_data(0x69, 0x2D)

# Convert the data
zGyro = data1 * 256 + data0
if zGyro > 32767 :
	zGyro -= 65536

# Output data to screen
print "Rotation in X-Axis : %d" %xGyro
print "Rotation in Y-Axis : %d" %yGyro
print "Rotation in Z-Axis : %d" %zGyro

[/codesyntax]

Testing

In a terminal window enter the following – sudo python L3GD20.py

Links
About $4 for one of these sensors

L3GD20 3-axis Gyroscope Sensor replace L3G4200D Angular velocity module