125 lines
2.8 KiB
C++
125 lines
2.8 KiB
C++
#include "Touchboard.h"
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void Touchboard::scan()
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{
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// For each key, set multiplexers and poll both capacitive sensors simultaneously
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for (int i = 0; i < 8; i++)
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{
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digitalWrite(MUX_A, bitRead(i, 0));
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digitalWrite(MUX_B, bitRead(i, 1));
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digitalWrite(MUX_C, bitRead(i, 2));
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unsigned int* values = sensor.sense(3);
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// Store the values received from the sensor poll into their respective positions
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keys[i] = values[0];
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keys[i + 8] = values[1];
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}
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}
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void Touchboard::calibrateKeys()
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{
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// Reset calibration data for all keys
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for (int i = 0; i < 16; i++)
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{
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em_averages[i] = 0;
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neutral_values[i] = 0;
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key_states[i] = false;
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keys[i] = false;
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}
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for (int i = 0; i < CALIBRATION_SAMPLES; i++) {
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// Repeatedly scan all keys
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scan();
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// Store the lowest read value as our baseline
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for (int j = 0; j < 16; j++) {
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if (keys[j] > neutral_values[j]) neutral_values[j] = keys[j];
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}
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}
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// After calibration is complete, initialize the averages to the baseline values established previously
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for (int i = 0; i < 16; i++) {
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em_averages[i] = neutral_values[i];
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}
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}
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bool Touchboard::update(int key)
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{
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int read_value = keys[key];
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float new_average = alpha * read_value + (1 - alpha) * em_averages[key];
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if (read_value - neutral_values[key] < deadzone)
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{
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// If we are in the deadzone, ignore any touch events, set the key to be untouched and update the moving average.
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if (key_states[key])
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em_averages[key] = neutral_values[key];
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else
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em_averages[key] = new_average;
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key_states[key] = false;
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}
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else
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{
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//If we are outside of the deadzone:
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if (read_value > em_averages[key] + threshold)
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{
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// If we just detected a touch, make the key touched, discard the previous moving average and trigger the callback.
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em_averages[key] = read_value;
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onKeyPress(key, key_states[key]);
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key_states[key] = true;
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}
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else
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{
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// Otherwise, just update the average.
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em_averages[key] = new_average;
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}
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}
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return key_states[key];
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}
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void Touchboard::setThreshold(uint16_t threshold)
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{
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this->threshold = threshold;
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EEPROM.put(0, threshold);
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}
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void Touchboard::setDeadzone(uint16_t deadzone)
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{
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this->deadzone = deadzone;
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EEPROM.put(4, deadzone);
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}
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void Touchboard::setAlpha(float alpha)
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{
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this->alpha = alpha;
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EEPROM.put(8, alpha);
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}
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int Touchboard::getThreshold()
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{
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return threshold;
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}
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int Touchboard::getDeadzone()
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{
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return deadzone;
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}
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float Touchboard::getAlpha()
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{
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return alpha;
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}
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Touchboard::Touchboard(void(*keyPressCallback)(int, bool)) :
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sensor(CapacitiveSensor(KEYBOARDPIN_COM, KEYBOARDPIN_1, KEYBOARDPIN_2)),
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onKeyPress(keyPressCallback)
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{
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EEPROM.get(0, threshold);
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EEPROM.get(4, deadzone);
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EEPROM.get(8, alpha);
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pinMode(MUX_A, OUTPUT);
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pinMode(MUX_B, OUTPUT);
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pinMode(MUX_C, OUTPUT);
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calibrateKeys();
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}
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