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Merge e365ab21f4 into 0f972f1cc3

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MickiusMousius 2024-09-02 10:07:57 -05:00 • committed by GitHub
commit 54c3daf376
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1 changed files with 31 additions and 9 deletions
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38
app/module/drivers/sensor/battery/battery_common.c
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@ -29,15 +29,37 @@ int battery_channel_get(const struct battery_value *value, enum sensor_channel c
return 0;
}
uint8_t lithium_ion_mv_to_pct(int16_t bat_mv) {
// Simple linear approximation of a battery based off adafruit's discharge graph:
// https://learn.adafruit.com/li-ion-and-lipoly-batteries/voltages
uint8_t lithium_ion_mv_to_pct(int16_t batt_mv) {
// Lookup table of slope formulas for calculating remaining battery capacity.
// The original values used to calculate slopes come from:
//
// https://blog.ampow.com/lipo-voltage-chart/
//
struct lookup_point {
int16_t millivolts;
int16_t percent;
};
if (bat_mv >= 4200) {
return 100;
} else if (bat_mv <= 3450) {
return 0;
static const struct lookup_point battery_lookup[] = {
{.millivolts = 4200, .percent = 100}, {.millivolts = 3870, .percent = 60},
{.millivolts = 3690, .percent = 10}, {.millivolts = 3610, .percent = 5},
{.millivolts = 3270, .percent = 0},
};
if (batt_mv > battery_lookup[0].millivolts) {
return battery_lookup[0].percent;
}
return bat_mv * 2 / 15 - 459;
for (int i = 1; i < ARRAY_SIZE(battery_lookup); i++) {
struct lookup_point one = battery_lookup[i - 1];
struct lookup_point two = battery_lookup[i];
if (batt_mv >= two.millivolts) {
const int t = batt_mv - one.millivolts;
const int dx = two.millivolts - one.millivolts;
const int dy = two.percent - one.percent;
return one.percent + dy * t / dx;
}
}
return battery_lookup[ARRAY_SIZE(battery_lookup) - 1].percent;
}