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Address feedback: Perform interpolation in code, proper use of struct & const

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MickiusMousius 2023-12-12 12:42:43 +10:30
parent f4c9b12d78
commit 86885c19bd
1 changed files with 23 additions and 22 deletions
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45
app/module/drivers/sensor/battery/battery_common.c
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@ -29,34 +29,35 @@ int battery_channel_get(const struct battery_value *value, enum sensor_channel c
return 0;
}
typedef struct {
int16_t millivolts;
float slope;
float offset;
} batt_est_formula;
uint8_t lithium_ion_mv_to_pct(int16_t bat_mv) {
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/
const batt_est_formula lipo_formula_lookup[9] = {
{.millivolts = 4200, .slope = 0, .offset = 100},
{.millivolts = 4150, .slope = 0.1, .offset = -320},
{.millivolts = 4110, .slope = 0.125, .offset = -423.75},
{.millivolts = 4020, .slope = 0.111, .offset = -366.22},
{.millivolts = 3870, .slope = 0.133, .offset = -454.68},
{.millivolts = 3690, .slope = 0.278, .offset = -1015.84},
{.millivolts = 3610, .slope = 0.063, .offset = -222.47},
{.millivolts = 3270, .slope = 0.015, .offset = -48.09},
//
struct lookup_point {
float millivolts;
float percent;
};
for (int i = 0; i < 9; i++) {
batt_est_formula current_formula = lipo_formula_lookup[i];
if (bat_mv >= current_formula.millivolts) {
float capacity = bat_mv * current_formula.slope + current_formula.offset;
return (uint8_t)capacity;
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 > 4200) {
return 100;
}
for (int i = 0; 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) {
float slope = (one.percent - two.percent) / (one.millivolts - two.millivolts);
float offset = one.percent - slope * one.millivolts;
float batt_percent = (slope * batt_mv) + offset;
return (uint8_t)batt_percent;
}
}