28029 Parallax Inc, 28029 Datasheet - Page 160

• 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 148 · Smart Sensors and Applications
Your Turn - Averaging the Calibration and Calibration Test Programs
The calibration and test calibration programs significantly improve the accuracy of your
digital compass. By incorporating averaging into both programs, the accuracy of your
digital compass will be further improved.
ACTIVITY #5: MOBILE MEASUREMENTS
This activity demonstrates how to replace the Debug Terminal with the Parallax Serial
LCD to make your digital compass mobile.
Connecting the Parallax Serial LCD with an Extension Cable
The Parallax Serial LCD is a definite source of magnetic field disturbance and needs to
be operated well away from the compass module. This is easily done with an extension
cable.
xSum = ABS(xSum)
x = xSum / 10
IF xSum // 10 >=5 THEN x = x + 1
IF sign = Negative THEN x = - x
sign = ySum.BIT15
ySum = ABS(ySum)
y = ySum / 10
IF ySum // 10 >=5 THEN y = y + 1
IF sign = Negative THEN y = - y
RETURN
√
√
√
√
Follow the steps in this activity to incorporate averaging into a copy of
CalibrateCompass.bs2. Instead of modifying the program's
subroutine
(TestCompassAveraged.bs2) and paste it over the one in your copy of
CalibrateCompass.bs2.
Run your modified copy of CalibrateCompass.bs2 and repeat the steps in
Activity #2.
Make a copy of TestCalibratedCompass.bs2, and modify it to perform averaging.
Repeat the accuracy tests in Activity #3. Your digital compass should perform
really well now.
just
copy
the
modified
' Take absolute value
' x = the average measurement
' Fraction > .5? Round up
' if xSum negative, negate x
' Store sign of ySum
' Take absolute value
' y = the average measurement
' Fraction > .5? Round up
' if ySum negative, negate y
subroutine
from
Compass_Get_Axes
this
program