85 lines
2.1 KiB
Python
85 lines
2.1 KiB
Python
# SPDX-License-Identifier: LGPL-3.0-or-later
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# Copyright (C) 2020 Daniel Thompson
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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 Sensing application.
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.. figure:: res/HeartApp.png
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:width: 179
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Screenshot of the heart rate application
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"""
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NAME = 'Heart'
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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.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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self._x = 0
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def background(self):
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wasp.watch.hrs.disable()
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del self._hrdata
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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.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 = 0xffc0
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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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