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Compass Module 3-Axis HMC5883L (#29133)
The Compass Module 3-Axis HMC5883L is a low-field magnetic sensing device with a digital interface.
The compass module converts any magnetic field to a differential voltage output on 3 axes. This voltage
shift is the raw digital output value, which can then be used to calculate headings or sense magnetic
fields coming from different directions. The module is designed for use with a large variety of
microcontrollers with different voltage requirements.
Features
3-Axis magneto-resistive sensor
1 to 2 degree compass heading accuracy
Wide magnetic field range (+/-8 gauss)
Fast 160 Hz maximum output rate
Precision in-axis sensitivity and linearity
Measures Earth’s magnetic field, from milli-gauss
to 8 gauss
Key Specifications
Power Requirements: 2.7 to 6.5 VDC
Communication Interface: I²C (up to 400 kHz)
Operating temperature: -22 to +185 °F
(-30 to +85 °C)
Dimensions: 0.73 x .65 in ( 1.8 x 1.7 cm)
Application Ideas
Auto and personal navigation
UAV systems
Robotic navigation
Location-based services (LBS)
Resources and Downloads
Check for the latest version of this document, free software, and example programs from the Compass
Module 3-Axis HMC5883L product page. Go to www.parallax.com and search for part number 29133.
Copyright © Parallax Inc.
Compass Module 3-Axis HMC5883L (#29133)
v1.0 11/4/2011 Page 1 of 6
Quick-Start Guide
The following is a very basic procedure to get started initializing and reading values from the Compass
Module. This module is equipped with 4.7 kΩ pull-up resistors on the SDA line and a 2.2K resistor on the
SCL line. There is no need for any external hardware to operate. The schematic is available from the
29133 product page at www.parallax.com.
1. With main power off, make the proper connections between the compass module and a
microcontroller as shown above. The voltage connected to the VIN pin should be the same as the
voltage powering the microcontroller communicating with the device.
2. Power on the device and load the BASIC Stamp or Propeller microcontroller sample code
provided on the 29133 product page.
Note: For other microcontrollers first, setup the module for continues output mode by writing
(0x3C) 0x00 to the MODE register (0x02). Once running in continues mode set a pointer to
OUTPUT_X_MSB by writing (0x3C) 0x03 to the device. Now the compass module will output raw
data from OUTPUT_X_MSB - OUTPUT_Y_LSB. The compass will automatically index through
these registers; there is no need to set pointers for each of these registers. The last step would
be to read from each of the six output registers, 8 bits of data per register. For more details on
these modes and registers please see the datasheet on the 29133 product page at
www.parallax.com.
Precautions
This module
is VERY sensitive to ferrous material, metal objects, magnets and power supplies,
etc. Any of these items in close range may affect performance. If you’re experiencing adverse
results, check your environment for anything that may influence magnetic fields. It is
recommended to connect the unit with wires, keeping it away from a breadboard.
Without tilt compensation the device will need to be level for accurate headings. For tilt
compensation, you will need an accelerometer. See the application notes available on the 29133
product page for details on tilt compensation.
Copyright © Parallax Inc.
Compass Module 3-Axis HMC5883L (#29133)
v1.0 11/4/2011 Page 2 of 6
Pin Descriptions
Pin
1
2
3
4
5
Name
GND
VIN
DRDY
SCL
SDA
Type
G
P
I
I
IO
Function
Ground
Supply Voltage – 2.7 to 6.5 VDC (module is regulated to 2.5VDC)
Data Ready, interrupt. (internally pulled high, see datasheet for details)
I²C Clock (Pulled high on module, Clock 160Hz Default)
I²C Data (Pulled high on module)
Module Dimensions
Copyright © Parallax Inc.
Compass Module 3-Axis HMC5883L (#29133)
v1.0 11/4/2011 Page 3 of 6
Device Information
The following information is taken from the HMC5883L datasheet; please refer to it for complete details.
It is available for download from the 29133 product page at
www.parallax.com.
Specifications
Characteristics
Average Current Draw
Field Range
Mag Dynamic Range
Resolution
Linearity
Hysteresis
Cross-Axis Sensitivity
Output Rate (ODR)
Measurement Period
Turn-on Time
Gain Tolerance
I²C Address
I²C Rate
I²C Hysteresis
Conditions
Idle Mode
Measurement Mode
Full Scale (FS) – Total applied
field (Typical)
3-bit gain control
VDD=3.0V, GN=2
±2.0 gauss input range
±2.0 gauss input range
Test Conditions: Cross field =0.5
gauss, Happlied = ±3 gauss
Continuous Measurement Mode
Single Measurement Mode
From receiving command to
data- ready
Ready for I²C commands
All gain/dynamic range settings
7-bit address
8-bit read address
8-bit write address
Controlled by I²C Master
Hysteresis of Schmitt trigger
inputs on SCL & SDA –
Fall (VDDIO=1.8V)
Rise (VDDIO=1.8V)
±25
±0.2%
0.75
6
200
±5
0X1E
0X3D
0X3C
400
75
160
Min
-
-
-8
±1
5
0.1
Typ
2
100
Max
-
-
+8
±8
Units
µA
gauss
gauss
milli-gauss
±% FS
Ppm
%FS/gauss
Hz
Hz
ms
µs
%
hex
hex
hex
kHz
0.2*VDDIO
0.8*VDDIO
Volts
Volts
Communication Protocol
The compass module communicates via a two-wire I²C bus system as a slave device. It supports
standard and fast modes, 100 kHz and 400 kHz, but does not support a high-speed mode. No external
pull-up resistors are required to support these standard and fast speed modes (4.7 kΩ pull-up resistors
are built into module). *See page 8 in the datasheet for I²C communication details.
Copyright © Parallax Inc.
Compass Module 3-Axis HMC5883L (#29133)
v1.0 11/4/2011 Page 4 of 6
Modes of Operation
The Compass Module has several modes that can be accessed from the I²C bus, whose primary purpose
is power management. All the modes are controlled by the Mode Register. The following section
describing modes, was taken from the Honeywell HMC5883L datasheet.
*See page 9 in the datasheet for more details.
Continuous-Measurement Mode
During continuous-measurement mode, the device continuously makes measurements, at user selectable
rate, and places measured data in data output registers. All registers maintain values while in continuous-
measurement mode and I²C bus is enabled for use by other devices on the network.
Single-Measurement Mode
This is the default power-up mode. During single-measurement mode, the device makes a single
measurement and places the measured data in data output registers. All registers maintain values while
in single-measurement mode. The I²C bus is enabled for use by other devices on the network while in
single-measurement mode.
Idle Mode
During this mode the device is accessible through the I²C bus, but major sources of power consumption
are disabled, such as, but not limited to, the ADC, the amplifier, and the sensor bias current. All registers
maintain values while in idle mode. The I²C bus is enabled for use by other devices on the network while
in idle mode.
Register List
This device is controlled and configured via a number of on-chip registers, The table below lists the
registers and their access. All address locations are 8 bits. For a detailed description of these registers
please access the datasheet on our Product Page.
Address Location
00
01
02
03
04
05
06
07
08
09
10
11
12
Register Name
Configuration A
Configuration B
Mode
Data Output X MSB
Data Output X LSB
Data Output Z MSB
Data Output Z LSB
Data Output Y MSB
Data Output Y LSB
Status
Identification A
Identification B
Identification C
Access
Read/Write
Read/Write
Read/Write
Read
Read
Read
Read
Read
Read
Read
Read
Read
Read
Copyright © Parallax Inc.
Compass Module 3-Axis HMC5883L (#29133)
v1.0 11/4/2011 Page 5 of 6
