acid-drop

- Hacking the planet from a LilyGo T-Deck using custom firmware
git clone git://git.acid.vegas/acid-drop.git
CapacitiveButton.ino (2903B)
      1 /*
      2  * A demo sketch that uses the AceButton Library
      3  * (https://github.com/bxparks/AceButton) and the CapitiveSense Library
      4  * (https://github.com/PaulStoffregen/CapacitiveSensor) to detect touches and
      5  * clicks of a capacitive switch.
      6  *
      7  * Prompted by questions from Gaston Loos.
      8  *
      9  * Brian T. Park 2018
     10  */
     11 
     12 #if defined(ESP32) || defined(ESP8266)
     13   #error ESP32 or ESP8266 not supported
     14 #endif
     15 
     16 #include <CapacitiveSensor.h>
     17 #include <AceButton.h>
     18 using namespace ace_button;
     19 
     20 /**
     21  * A subclass of ButtonConfig that emulates a mechanical switch connected to a
     22  * pull-up resistor on the input pin. A "touch" sends a LOW signal, just like a
     23  * mechnical switch.
     24  */
     25 class CapacitiveConfig: public ButtonConfig {
     26   public:
     27     CapacitiveConfig(CapacitiveSensor& sensor):
     28       mSensor(sensor) {}
     29 
     30   protected:
     31     // Number of iterations to sample the capacitive switch. Higher number
     32     // provides better smoothing but increases the time taken for a single read.
     33     static const uint8_t kSamples = 30;
     34 
     35     // The threshold value which is considered to be a "touch" on the switch.
     36     static const long kTouchThreshold = 100;
     37 
     38     int readButton(uint8_t /*pin*/) override {
     39       long total =  mSensor.capacitiveSensor(kSamples);
     40       return (total > kTouchThreshold) ? LOW : HIGH;
     41     }
     42 
     43   private:
     44     CapacitiveSensor& mSensor;
     45 };
     46 
     47 // Timeout for a single read of the capacitive switch.
     48 static const unsigned long TIMEOUT_MILLIS = 10;
     49 
     50 // I used a 1M resistor between pins 4 (send) & metal plate, and a 1K resistor
     51 // between the plate and pin 6 (receive). Try adjusting the
     52 // CapacitiveConfig::kTouchThreshold value for other resistor values.
     53 CapacitiveSensor capSensor(4, 6);
     54 
     55 CapacitiveConfig buttonConfig(capSensor);
     56 AceButton button(&buttonConfig);
     57 
     58 void handleEvent(AceButton* /* button */, uint8_t eventType,
     59     uint8_t /* buttonState */) {
     60   switch (eventType) {
     61     case AceButton::kEventPressed:
     62       Serial.println(F("Pressed"));
     63       break;
     64     case AceButton::kEventClicked:
     65       Serial.println(F("Clicked"));
     66       break;
     67     case AceButton::kEventDoubleClicked:
     68       Serial.println(F("DoubleClicked"));
     69       break;
     70   }
     71 }
     72 
     73 void setup() {
     74   Serial.begin(115200);
     75   while (!Serial); // Leonardo/Micro
     76 
     77   // Set the timeout to 10 millisecond so that AceButton::check()
     78   // can have about 4-5 iterations during the 50 millisecond debouncing time.
     79   capSensor.set_CS_Timeout_Millis(TIMEOUT_MILLIS);
     80 
     81   // Configure the button using CapacitiveConfig.
     82   buttonConfig.setFeature(ButtonConfig::kFeatureClick);
     83   buttonConfig.setFeature(ButtonConfig::kFeatureDoubleClick);
     84   buttonConfig.setEventHandler(handleEvent);
     85 }
     86 
     87 void loop() {
     88   unsigned long start = millis();
     89   button.check();
     90 
     91   // check on performance in milliseconds
     92   unsigned long duration = millis() - start;
     93   if (duration > TIMEOUT_MILLIS) {
     94     Serial.print(F("duration: "));
     95     Serial.println(duration);
     96   }
     97 }