diff options
Diffstat (limited to 'wasp')
| -rw-r--r-- | wasp/drivers/battery.py | 50 |
1 files changed, 42 insertions, 8 deletions
diff --git a/wasp/drivers/battery.py b/wasp/drivers/battery.py index c13f117..5bf06cd 100644 --- a/wasp/drivers/battery.py +++ b/wasp/drivers/battery.py @@ -1,35 +1,69 @@ # SPDX-License-Identifier: LGPL-3.0-or-later # Copyright (C) 2020 Daniel Thompson -# Generic lithium ion battery driver - +"""Generic lithium ion battery driver +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +""" from machine import Pin, ADC class Battery(object): + """Generic lithium ion battery driver. + + .. automethod:: __init__ + """ + def __init__(self, battery, charging, power=None): + """Specify the pins used to provide battery status. + + :param Pin battery: The ADC-capable pin that can be used to measure + battery voltage. + :param Pin charging: A pin (or Signal) that reports the charger status. + :param Pin power: A pin (or Signal) that reports whether the device + has external power, defaults to None (which means + use the charging pin for power reporting too). + """ self._battery = ADC(battery) self._charging = charging self._power = power def charging(self): + """Get the charging state of the battery. + + :returns: True if the battery is charging, False otherwise. + """ return self._charging.value() def power(self): + """Check whether the device has external power. + + :returns: True if the device has an external power source, False + otherwise. + """ if self._power: return self._power.value() return self._charging.value() def voltage_mv(self): - # Assumes a 50/50 voltage divider and a 3.3v power supply + """Read the battery voltage. + + Assumes a 50/50 voltage divider and a 3.3v power supply + + :returns: Battery voltage, in millivolts. + """ raw = self._battery.read_u16() return (2 * 3300 * raw) // 65535 def level(self): - # This is a trivial battery level estimation approach. It is assumes - # the discharge from 4v to 3.5v is roughly linear and 4v is 100% and - # that 3.5v is 5%. Below 3.5v the voltage will start to drop pretty - # sharply to we will drop from 5% to 0% pretty fast... but we'll - # live with that for now. + """Estimate the battery level. + + The current the estimation approach is extremely simple. It is assumes + the discharge from 4v to 3.5v is roughly linear and 4v is 100% and + that 3.5v is 5%. Below 3.5v the voltage will start to drop pretty + sharply to we will drop from 5% to 0% pretty fast... but we'll + live with that for now. + + :returns: Estimate battery level in percent. + """ mv = self.voltage_mv() level = ((19 * mv) // 100) - 660 if level > 100: |