HMR3100
SENSOR PRODUCTS
Solid State Electronics Center • www.magneticsensors.com • (800) 323-8295 • Page 2
INTRODUCTION
The Honeywell HMR3100 is a low cost electronic compassing solution for use in consumer electronics and personal
navigation products. Honeywell’s magnetoresistive sensors are utilized to provide enhanced reliability and accuracy
in a small, two-axis, solid state compass design. This compass solution is easily integrated into systems using a
simple UART interface and binary data format. Performance is optimized for a horizontal circuit board orientations.
SPECIFICATIONS
Characteristics Conditions
Min
Typ
Max
Units
Heading
Accuracy Level
± 5
deg RMS
Resolution 0.5 deg
Repeatability
± 3
deg
Magnetic Field
Range Maximum Magnetic Flux Density
± 2
gauss
Resolution 6 milli-gauss
Electrical
Input Voltage Unregulated 2.6 3 5 volts DC
Current Normal Mode (Average)
Sleep Mode
Calibration
0.1
6.1
0.2
7.3
0.5
1
17.3
mA
µA
mA
Digital Interface
USART USART 9600.N.8.1 2400 9600 19200 Baud
Update Continuous or Polled - 2 20 Hz
Connector 8-Pin -
Physical
Dimensions Circuit Board Assembly 19 x 19 x
4.5
mm
Weight 1.5 grams
Environment
Temperature Operating
Storage
0
-40
-
-
+70
+110
°C
°C
Circuit Description
The HMR3100 Digital Compass Solution circuit board includes the basic magnetic sensors and electronics to provide
a digital indication of heading. The HMR3100 has a Honeywell HMC1022 two-axis magnetic sensor on board. The
HMR3100 allows users to derive compassing (heading) measurements when the board is in a reasonably horizontal
(flat) position.
The HMR3100 circuit starts with the HMC1022 two-axis magnetic sensors providing X and Y axis magnetic sensing of
the earth’s field. These sensors are supplied power by a switching transistor to conserve power with battery operated
products. The sensor output voltages are provided to a dual operational amplifier and then to analog to digital
