± 2g / 4g / 8g / 16g Tri-axis Digital
Accelerometer Technical
Reference Manual
PART NUMBER:
KX132-1211
Rev. 1.0
31-Jul-2019
36 Thornwood Dr.
–
Ithaca, NY 14850
© 2019 Kionix
–
All Rights Reserved
tel: 607-257-1080 – fax:607-257-1146
893-12874-1907311402-0.17
www.kionix.com -
Page
61
of
73
2.3
Directional-Tap Detection Feature Description
The Directional-Tap
TM
Detection feature of the KX132-1211 recognizes single and double tap inputs and reports the
acceleration axis and direction that each tap occurred. Eight performance parameters, as well as a user-selectable
ODR are used to configure the KX132-1211 for a desired tap detection response.
Performance Index
The Directional-Tap
TM
detection algorithm uses low and high thresholds to help determine when a tap event has
occurred. A tap event is detected when the previously described jerk summation exceeds the low
threshold (TTL) for
more than the tap detection low limit, but less than the tap detection high limit as contained
in FTD. Samples that exceed
the high limit (TTH) will be ignored. Figure 17 shows an example of a single tap event meeting the performance index
criteria.
Figure 17:
Jerk Summation vs Threshold
3.14
3.15
3.16
3.17
3.18
3.19
3.2
3.21
0
20
40
60
80
100
120
140
160
180
Calculated Performance Index
time(sec)
je
rk
(
c
o
u
n
ts
)
PI
TTL
: Sampled Data