128 lines
3.4 KiB
Python
128 lines
3.4 KiB
Python
# SPDX-License-Identifier: LGPL-3.0-or-later
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# Copyright (C) 2020 Daniel Thompson
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"""Heart rate monitor
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~~~~~~~~~~~~~~~~~~~~~
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A graphing heart rate monitor using a PPG sensor.
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.. figure:: res/HeartApp.png
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:width: 179
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This program also implements some (entirely optional) debug features to
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store the raw heart data to the filesystem so that the samples can be used
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to further refine the heart rate detection algorithm.
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To enable the logging feature select the heart rate application using the
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watch UI and then run the following command via wasptool:
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.. code-block:: sh
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./tools/wasptool --eval 'wasp.system.app.debug = True'
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Once debug has been enabled then the watch will automatically log heart
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rate data whenever the heart rate application is running (and only
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when it is running). Setting the debug flag to False will disable the
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logging when the heart rate monitor next exits.
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Finally to download the logs for analysis try:
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.. code-block:: sh
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./tools/wasptool --pull hrs.data
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"""
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import wasp
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import machine
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import ppg
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class HeartApp():
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"""Heart rate monitor application."""
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NAME = 'Heart'
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def __init__(self):
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self._debug = False
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self._hrdata = None
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def foreground(self):
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"""Activate the application."""
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wasp.watch.hrs.enable()
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# There is no delay after the enable because the redraw should
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# take long enough it is not needed
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draw = wasp.watch.drawable
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draw.fill()
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draw.set_color(wasp.system.theme('bright'))
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draw.string('PPG graph', 0, 6, width=240)
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wasp.system.request_tick(1000 // 8)
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self._hrdata = ppg.PPG(wasp.watch.hrs.read_hrs())
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if self._debug:
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self._hrdata.enable_debug()
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self._x = 0
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def background(self):
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wasp.watch.hrs.disable()
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self._hrdata = None
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def _subtick(self, ticks):
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"""Notify the application that its periodic tick is due."""
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draw = wasp.watch.drawable
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spl = self._hrdata.preprocess(wasp.watch.hrs.read_hrs())
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if len(self._hrdata.data) >= 240:
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draw.set_color(wasp.system.theme('bright'))
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draw.string('{} bpm'.format(self._hrdata.get_heart_rate()),
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0, 6, width=240)
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# Graph is orange by default...
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color = wasp.system.theme('spot1')
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# If the maths goes wrong lets show it in the chart!
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if spl > 100 or spl < -100:
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color = 0xffff
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if spl > 104 or spl < -104:
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spl = 0
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spl += 104
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x = self._x
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draw.fill(0, x, 32, 1, 208-spl)
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draw.fill(color, x, 239-spl, 1, spl)
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x += 2
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if x >= 240:
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x = 0
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self._x = x
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def tick(self, ticks):
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"""This is an outrageous hack but, at present, the RTC can only
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wake us up every 125ms so we implement sub-ticks using a regular
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timer to ensure we can read the sensor at 24Hz.
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"""
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t = machine.Timer(id=1, period=8000000)
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t.start()
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self._subtick(1)
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wasp.system.keep_awake()
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while t.time() < 41666:
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pass
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self._subtick(1)
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while t.time() < 83332:
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pass
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self._subtick(1)
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t.stop()
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del t
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@property
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def debug(self):
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return self._debug
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@debug.setter
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def debug(self, value):
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self._debug = value
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if value and self._hrdata:
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self._hrdata.enable_debug()
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