28029 Parallax Inc, 28029 Datasheet - Page 254

• 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 242 · Smart Sensors and Applications
Graphing Ollie Acceleration
Figure 6-15 shows a graph of the accelerometer's y-axis for the first of two ollies that
were datalogged with the next example program. Each step from Figure 6-14 is marked
on the graph.
This first ollie was a little deficient in Figure 6-14 steps b and c, so the back of the board
didn't quite meet the back foot in step e. Note that the impact of the board during step f
was 3.5 g. The highs and lows that follow step f resemble the oscillations when a bell is
struck. This is partially due to the board's vibration and partially due the turbulence of
the gas inside the accelerometer caused by the impact.
Figure 6-16 shows the data for a slightly better ollie. It was a little higher, and it made it
to step e gracefully. Notice that step a to b is steeper, and gets to -1.25 g before rising to
over 1 g for steps c and d. These values, which are larger than the ones from the previous
graph, indicate a higher ollie. Notice also that the impact was below 3 g, because the
skater was not trying to catch up with the board on the way down.
-0.5
-1.5
3.5
2.5
1.5
0.5
-1
a, b
3
2
1
0
170
190
Acceleration vs Tim e for First Ollie
c, d e
210
tim e (m s)
230
250
270
f
Figure 6-15
Acceleration during an
Ollie