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Exponential smoothing on expression pedal ADC (factor 8) to filter noise

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ash
2026-07-04 05:05:35 +00:00
parent 33c9dd10c0
commit 4f58d4b8e6
2 changed files with 6 additions and 2 deletions
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include/expression_pedal.h
+1
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@@ -29,6 +29,7 @@ private:
uint32_t last_read_time; uint32_t last_read_time;
uint16_t current_raw; uint16_t current_raw;
uint16_t smoothed_raw;
uint16_t cal_min; uint16_t cal_min;
uint16_t cal_max; uint16_t cal_max;
src/expression_pedal.cpp
+5 -2
View File
@@ -10,6 +10,7 @@ ExpressionPedal::ExpressionPedal(uint8_t adc_pin)
, midi_cc(4) , midi_cc(4)
, last_read_time(0) , last_read_time(0)
, current_raw(0) , current_raw(0)
, smoothed_raw(0)
, cal_min(36) , cal_min(36)
, cal_max(1180) , cal_max(1180)
{ {
@@ -21,7 +22,8 @@ void ExpressionPedal::begin() {
pinMode(adc_pin, INPUT); pinMode(adc_pin, INPUT);
delay(10); delay(10);
current_raw = analogRead(adc_pin); current_raw = analogRead(adc_pin);
current_value = adc_to_midi(current_raw); smoothed_raw = current_raw;
current_value = adc_to_midi(smoothed_raw);
last_sent_value = current_value; last_sent_value = current_value;
Serial.printf("[EXP] Starting: raw ADC=%d -> MIDI=%d (cal: %d-%d)\n", Serial.printf("[EXP] Starting: raw ADC=%d -> MIDI=%d (cal: %d-%d)\n",
current_raw, current_value, cal_min, cal_max); current_raw, current_value, cal_min, cal_max);
@@ -34,7 +36,8 @@ void ExpressionPedal::update(UsbMidiTransport& midi) {
last_read_time = now; last_read_time = now;
current_raw = analogRead(adc_pin); current_raw = analogRead(adc_pin);
uint8_t new_value = adc_to_midi(current_raw); smoothed_raw = (smoothed_raw * 7 + current_raw + 4) / 8;
uint8_t new_value = adc_to_midi(smoothed_raw);
if (new_value > current_value + HYSTERESIS || if (new_value > current_value + HYSTERESIS ||
new_value + HYSTERESIS < current_value || new_value + HYSTERESIS < current_value ||