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Added shake detection #13

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Merged
merged 4 commits into from
Nov 27, 2017
Merged

Added shake detection #13

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0325149
Added shake detection
kattni Nov 26, 2017
82d96bd
Syntax update
kattni Nov 26, 2017
aba03b0
Updated with requested changes
kattni Nov 27, 2017
11a318b
Explanation moved to internal comment
kattni Nov 27, 2017
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27 changes: 27 additions & 0 deletions adafruit_lis3dh/lis3dh.py
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,8 @@
import ustruct as struct

from micropython import const
import time
import math

# Register addresses:
REG_OUTADC1_L = const(0x08)
Expand Down Expand Up @@ -113,6 +115,31 @@ def acceleration(self):

return (x / divider * 9.806, y / divider * 9.806, z / divider * 9.806)

def shake(self, shake_threshold=30, avg_delay=0.01, avg_count=10):
"""Detect when the accelerometer is shaken. This takes a series of readings
from acceleration, finds the average, then calculates the total acceleration
by taking the square root of the sum of squares, i.e. sqrt(X*X + Y*Y + Z*Z).
The result is compared to a threshold to determine if the device has been
shaken.
Optional parameters:
shake_threshold - Increase or decrease to change shake sensitivity. This
requires a minimum value of 10. 10 is the total
acceleration if the board is not moving, therefore
anything less than 10 will erroneously report a constant
shake detected. (Default 30)
avg_delay - The speed in seconds at which the series of values used for the
average acceleration are taken. (Default 0.01)
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I think it'd be clearer if this was total delay. That way its easy to tell how long it will take. Then, in the sleep just divide total delay by the number of samples.

avg_count - The number of readings taken and used for the average
acceleration. (Default 10)
"""
shake_accel = (0, 0, 0)
for i in range(avg_count):
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Please put the internal explanation here after a #. The """ comment should only have the "public" info.

shake_accel = tuple(map(sum, zip(shake_accel, self.acceleration)))
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This is pretty tricky. How about adding a comment explaining how it works.

time.sleep(avg_delay)
avg = tuple(value / avg_count for value in shake_accel)
total_accel = math.sqrt(sum(map(lambda x: x * x, avg)))
return total_accel > shake_threshold

def read_adc_raw(self, adc):
"""Retrieve the raw analog to digital converter value. ADC must be a
value 1, 2, or 3.
Expand Down