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# SPDX-License-Identifier: LGPL-3.0-or-later
# Copyright (C) 2020 Daniel Thompson
import wasp
import machine
import ppg
class HeartApp():
"""Heart Rate Sensing application.
.. figure:: res/HeartApp.png
:width: 179
Screenshot of the heart rate application
"""
NAME = 'Heart'
def foreground(self):
"""Activate the application."""
wasp.watch.hrs.enable()
# There is no delay after the enable because the redraw should
# take long enough it is not needed
draw = wasp.watch.drawable
draw.fill()
draw.string('PPG graph', 0, 6, width=240)
wasp.system.request_tick(1000 // 8)
self._hrdata = ppg.PPG(wasp.watch.hrs.read_hrs())
self._x = 0
def background(self):
wasp.watch.hrs.disable()
del self._hrdata
def _subtick(self, ticks):
"""Notify the application that its periodic tick is due."""
draw = wasp.watch.drawable
spl = self._hrdata.preprocess(wasp.watch.hrs.read_hrs())
if len(self._hrdata.data) >= 240:
draw.string('{} bpm'.format(self._hrdata.get_heart_rate()),
0, 6, width=240)
# Graph is orange by default...
color = wasp.system.theme('spot1')
# If the maths goes wrong lets show it in the chart!
if spl > 100 or spl < -100:
color = 0xffff
if spl > 104 or spl < -104:
spl = 0
spl += 104
x = self._x
draw.fill(0, x, 32, 1, 208-spl)
draw.fill(color, x, 239-spl, 1, spl)
x += 2
if x >= 240:
x = 0
self._x = x
def tick(self, ticks):
"""This is an outrageous hack but, at present, the RTC can only
wake us up every 125ms so we implement sub-ticks using a regular
timer to ensure we can read the sensor at 24Hz.
"""
t = machine.Timer(id=1, period=8000000)
t.start()
self._subtick(1)
wasp.system.keep_awake()
while t.time() < 41666:
pass
self._subtick(1)
while t.time() < 83332:
pass
self._subtick(1)
t.stop()
del t
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