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Actually use the devicetree calibration coeffs

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rbaron 2023-03-19 10:14:07 +01:00
parent 2f7a25e266
commit b34bc60a0a
1 changed files with 3 additions and 10 deletions
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13
code/nrf-connect/prstlib/src/adc.c
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@ -93,18 +93,11 @@ static inline float eval_poly(const int coeffs[3], float x) {
static inline float get_soil_moisture_percent(float battery_voltage,
int16_t raw_adc_output) {
const float x = battery_voltage;
const float dry = -11.7f * x * x + 101.0f * x + 306.0f;
const float wet = 3.42f * x * x - 4.98f * x + 19.0f;
const float dry = eval_poly(dry_coeffs, x);
const float wet = eval_poly(wet_coeffs, x);
const float percent = (raw_adc_output - dry) / (wet - dry);
LOG_INF("Read soil moisture: %.2f | Raw %u | Batt: %.2f | Dry: %.2f | Wet: %.2f",
100.0f * percent, raw_adc_output, x, dry, wet);
const float dry2 = eval_poly(dry_coeffs, x);
const float wet2 = eval_poly(wet_coeffs, x);
const float percent2 = (raw_adc_output - dry2) / (wet2 - dry2);
LOG_INF("Read soil moisture 2: %.2f | Raw %u | Batt: %.2f | Dry: %.2f | Wet: %.2f",
100.0f * percent2, raw_adc_output, x, dry2, wet2);
100.0f * percent, raw_adc_output, x, dry, wet);
return percent;
}