28029 Parallax Inc, 28029 Datasheet - Page 106

• Manufacturer Part Number: 28029
• Description: KIT PARTS SMART SENSORS W/TEXT
• Manufacturer: Parallax Inc

Specifications of 28029

• Accessory Type: Parts Kit
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: BASIC Stamp® or Javelin Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant
• Other names: 28029PAR

Page 94 · Smart Sensors and Applications
Example Program: VertWheelRotation.bs2
This program displays your board's angle of rotation as shown in Figure 3-20 at the
beginning of this activity, page 92.
The General Case
The angle of rotation (θ) is the inverse tangent or arctangent of the component of gravity
acting on the Memsic 2125’s Y sensing (A
the X sensing axis (A
rotates both sensing axes by θ. By applying a couple of geometry identities, θ is also inside
the two triangles that show the components of gravity acting on each of the accelerometers
sensing axes (x
component acting on y
demonstrates that the angle of rotation θ is in fact the arctangent of A
tan
tan
θ
A
A
Y
X
=
tan
−
θ
=
m
1
and y
=
g
g
(
tan
−
A
A
cos
1
sin
X
X
⎛
⎜
⎜
⎝
Y
m
). The figure below shows the MX2125 tilted at an angle θ, which
m
θ
is A
A
A
). The component of gravity acting on x
θ
θ
)
Y
X
=
Y
=
⎞
⎟
⎟
⎠
tan
= g sinθ. After applying the trig identities shown on the right, it
tan
−
θ
1
⎛
⎜
⎜
⎝
A
A
X
Y
Y
⎞
⎟
⎟
⎠
) divided by the component of gravity acting on
m
is A
Y
/A
X
X
.
= g cosθ, and the