122-28029 Parallax Inc, 122-28029 Datasheet - Page 132

• Manufacturer Part Number: 122-28029
• Description: GUIDE STUDENT SMART SENSORS
• Manufacturer: Parallax Inc

Specifications of 122-28029

• Accessory Type: Manual
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Smart Sensors
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

Page 120 · Smart Sensors and Applications
trigonometry identities, it turns out that the angle θ is the arctangent of −y/x. So in
addition to accelerometer rotation, the compass module's angle from north is another
value that can be determined using the PBASIC
ACTIVITY #1: CONNECTING AND TESTING THE COMPASS MODULE
In this activity, you will connect the compass module to the BASIC Stamp and run a test
program. This will verify that the electrical connections are correct and the module is in
working order.
Connecting the Compass Module
The Hitachi HM55B Compass module needs connections to Vdd and Vss (power and
ground) and three communication line connections to the BASIC Stamp.
Parts Required
(1) Hitachi HM55B Compass Module
(6) Jumper wires
There are no external resistors or capacitors required; they are all built onto the module.
Figure 4-2
Compass Module Sensing Axes
tan
tan
θ
=
tan
−
θ
ATN
1
=
(
tan
−
−
N
1
operator.
N
⎛ −
⎜ ⎜
⎝
θ
cos
sin
x
)
y
=
⎞
⎟ ⎟
⎠
θ
tan
θ
=
−
−
1
x
y
⎛ −
⎜ ⎜
⎝
x
y
⎞
⎟ ⎟
⎠