Pullup pulldown (#42)

* describing how to connect the button
* links added
* support for pullup

README.md

@@ -26,7 +26,7 @@ Features
 - Configurable via Web-Interface so no need to compile your own firmware, you just need to download and to flash the microcontroller (see https://tasmota.github.io/docs/Getting-Started/#flashing for example for how to flash a D1 mini). Please note: Those values can be changed by anyone having access to your network since there is no authentication/authorization (yet) implemented! 
 - Acts as normal SIP-Client so it can be used not only with TR064-enabled devices but every SIP-Server/SIP-enabled hardware
 - Can can be initiated via 433 MHz signal (e.g. wireless doorbell sender)
-- Can can be initiated via button (e.g. a simple push button and/or optocoppler to make an existent doorbell a smart doorbell). The call gets initiated when the pin gets HIGH, so when connecting a button you would have to use pulldown resistor
+- Can can be initiated via button/momentary switch (e.g. a simple push button and/or optocoppler to make an existent doorbell a smart doorbell). Supported pin modes are pullup (with and w/o internal resistor, LOW indicates button pressed) and pulldown (HIGH indicates button pressed)
 - Can switch GPIO pin on ring (e.g. to visualize via LED and/or do some action on another microcontroller)
 - Can publish mqtt messages on ring so other tasks can be done via integration platforms like ioBroker, home assistant, node red, ...
 

configuration.json

@@ -78,6 +78,15 @@
         "type": "int16_t",
         "value": "-1"
     },
+    {
+        "name": "button_gpiopin_mode",
+        "label": "Input mode of the GPIO Pin to connect a push button which triggers a call",
+        "type": "char",
+        "length": 20,
+	"control": "select",
+	"options": ["", "PULLUP", "PULLUP (internal)", "PULLDOWN"], 
+        "value": ""
+    },
     {
         "name": "switch_gpiopin",
         "label": "GPIO Pin switched HIGH when button press detected",
@@ -134,4 +143,4 @@
         "value": "Doorbell #1"
     }
 
-]
+]

src/main.cpp

@@ -29,6 +29,9 @@ unsigned long dialingStartedAt;
 // RCSWITCH
 RCSwitch mySwitch = RCSwitch();
 
+// gpio input can be configured pullup and pulldown, so HIGH or LOW could signal a button press
+int pin_pressed_is = HIGH;
+
 // Tasks
 struct task
 {
@@ -94,9 +97,28 @@ void inputPinBegin(void)
 {
   if (configManager.data.button_gpiopin > 0)
   {
+    Serial.print(F("GPIO "));
     Serial.print(configManager.data.button_gpiopin);
-    Serial.println(F(" configured for input button"));
+    Serial.print(F(" configured for input button "));
     pinMode(configManager.data.button_gpiopin, INPUT);
+
+    if (strcmp("PULLUP", configManager.data.button_gpiopin_mode) == 0)
+    {
+      Serial.println(F("pullup"));
+      pin_pressed_is = LOW;
+    }
+    else if (strcmp("PULLUP (internal)", configManager.data.button_gpiopin_mode) == 0)
+    {
+      Serial.println(F("pullup (internal)"));
+      pinMode(configManager.data.button_gpiopin, INPUT_PULLUP);
+      pin_pressed_is = LOW;
+    }
+    else 
+    {
+      // PULLDOWN
+      Serial.println(F("pulldown"));
+      pin_pressed_is = HIGH;
+    }
   }
   else
   {
@@ -187,8 +209,9 @@ void dial(void)
 
 void buttonLoop(void)
 {
-  if (digitalRead(configManager.data.button_gpiopin) == HIGH)
+  if (digitalRead(configManager.data.button_gpiopin) == pin_pressed_is)
   {
+    Serial.print(F("GPIO "));
     Serial.print(configManager.data.button_gpiopin);
     Serial.println(F(" button press detected"));
     dial();