Pin Change Interrupt on "any" pin.

  • I found this page:

    Iv seen it on other places as well. Is there anyone here that is expert on Arduino and deep sleep/interrupt.

    Is it possible to sleep the Node and then wake up and run a "send-data-loop" if there is a change on any pin. Not just pin 2 and 3 (Arduino Pro Mini)


  • Yes, that is possible , but for now only when using only the interrupt pin to wake up the node. If you want to periodically send a sensor value you'll need to use another way. (Or be patient, as we are trying to find out what and why 😁 )

  • I am about to use the EnableInterrupt library to catch interrupts on lots of pins on a mega. I had to comment out in the header file where it tried to take control of the external interrupts. Yet to test though (gate controller replacement sketch).

  • Thanks for you answers!

    In this particular case I dont want to send data periodically. It is a Door/Lock node. I just want it to wake up when there is a change on one of the pins, run a Loop and then fall back to sleep.

    If I could use more pins I could have 1 node monitor 2 doors/locks.

    Will we see the result of your work (Multiple pin interrupts AND timed interrupts) her on mySensors later?

    Would be great!

  • Hardware Contributor

    @popunonkok sleep is implemented in the MySensors library, with or without interups:

    Int 2 + 3 can detect FALLING, CHANGE and RISING while the other pins can be used for interrupt but only detect CHANGE.

  • I found a library for this, I have not tried myself

    Also a post on Arduino forum

  • This library work great for me. You only need disable external interrupts before include header.

    #define EI_NOTEXTERNAL // Do not use external interrupts in EnableInterrupt lib
    #include <EnableInterrupt.h>

  • @popunonkok

    Well here's the first example of some code that works for me. It's a house controller mounted on a pulse switch (for a standard NL/BE/FR/DE switch box). Own developed PCB that can handle 4 switches, so needed to find a way to be able to sens all our inputs.
    I used the "Button" library to de-clutter the code a bit, and I followed the MySensors way of setting up the program (with defines). That's because I want to deploy a whole bunch of these, so I can adjust some settings quick and then shoot the sketch in the MCU.
    At first I included a sensor function as well but as the standard sketch grew too big I axed that.
    I'll only give the relevant parts of my code now, as I'm not finished yet. Still working on the part where the connection with the GW is lost and reinstated. As this project can also be used as a light switch, it should ALWAYS work. So after the communication is restored the node has to send all the states to the GW again.

    #define PULLUP true        
    #define INVERT true        
    #define bounceTime 20             // A debounce time of 20 milliseconds usually works well for tactile button switches.
    #include <Button.h>
    #include <PinChangeInt.h>
    #define buttApin  14              // Arduino Digital I/O pin numbers for connected buttons 
    #define buttBpin  15              // when connected to '`official' PCB.
    #define buttCpin  8
    #define buttDpin  9
    bool battPower = true;
    int inputPin[5] = {0, 0, 0, 0, 0};          // State machine registers
    int actuatorPin[2] = {0, 0};
    int function[4] = {0, 0, 0, 0};
    bool safetyBttn[4] = {0, 0, 0, 0};
    bool reqAck[4] = {0, 0, 0, 0};
    bool inState[5] = {0, 0, 0, 0, 0};
    bool longPr[5] = {0, 0, 0, 0, 0};
    bool outState[4] = {0, 0, 0, 0};
    Button BtnA(buttApin, PULLUP, INVERT, bounceTime);    
    Button BtnB(buttBpin, PULLUP, INVERT, bounceTime);
    Button BtnC(buttCpin, PULLUP, INVERT, bounceTime);
    Button BtnD(buttDpin, PULLUP, INVERT, bounceTime);
    attachPinChangeInterrupt(inputPin[ChanA], ChanA_ISR, CHANGE);
    attachPinChangeInterrupt(inputPin[ChanB], ChanB_ISR, CHANGE);
    attachPinChangeInterrupt(inputPin[ChanC], ChanC_ISR, CHANGE);
    attachPinChangeInterrupt(inputPin[ChanD], ChanD_ISR, CHANGE);
    void ChanA_ISR()
       pinChanged = ChanA;
       inState[ChanA] =;
    void ChanB_ISR()
       pinChanged = ChanB;
       inState[ChanB] =;
    void ChanC_ISR()
      pinChanged = ChanC;
      inState[ChanC] =;
    void ChanD_ISR()
      pinChanged = ChanD;
      inState[ChanD] =;

    So when the node wakes up from sleep the variable pinChanged carries the number of the pin that has made it enter the ISR. That can be used to take action. After everything is handled pinChangedis set to the resting value (255 in this case).

    Depending on whether the circuit is powered by a battery or a 5V supply the node enters sleep state or simply loops without doing anything. When sleeping I use sleep(0xff,0x00, 0xff, 0x00, 0); When using any other call to sleep, it will not work (the node never wakes up). So I got a hint from one of the developers how to solve it, and I have yet to try that. But I'll keep you updated here (and the other thread).

    I hope this helps you a bit further.

  • Well, that's embarrassing... I gave these tips last week, but it appears now that I have been surpassed by updates to the MyS library. The sleep command i issued here now leads to a loop, the node will not sleep. The changes to the library are intentional, as they make MySensors compliant with the designrules from Atmel/MicroChip.
    I have tried another library by the same author (EnableInterrupt) but to no avail.

    Back to the sketchboard...

  • @DavidZH

    I have been working on a similar problem lately and just noticed your post. I also tried using libraries at first, but ran into issues due to bouncing signals from the buttons. The pin change interrupt service routine tried to detect which button was pressed, but since the signal was bouncing, button presses were missed. The system would wake up but not call the appropriate callback function associated with the pin.

    I put together a sketch that works for me. It involves setting up the change pin interrupts, detecting which button is pressed and some provisions for debouncing the signal. It uses a small hack to leave the timed sleep function on pin change interrupts. I did not have trouble entering sleep like you did.

    Please note that this sketch uses the current MySensors development branch.

    The sketch is below, I hope it helps.

     * The MySensors Arduino library handles the wireless radio link and protocol
     * between your home built sensors/actuators and HA controller of choice.
     * The sensors forms a self healing radio network with optional repeaters. Each
     * repeater and gateway builds a routing tables in EEPROM which keeps track of the
     * network topology allowing messages to be routed to nodes.
     * Created by Henrik Ekblad <>
     * Copyright (C) 2013-2015 Sensnology AB
     * Full contributor list:
     * Documentation:
     * Support Forum:
     * This program is free software; you can redistribute it and/or
     * modify it under the terms of the GNU General Public License
     * version 2 as published by the Free Software Foundation.
     * Interrupt driven binary switch example with dual pin change interrupts
     * Author: Francis Reynders
     * MySensors does not support pin change interrupts currently. This sketch
     * initializes pin change interrupts and combines it with MySensors sleep
     * functions. Some hacking is required to get out of the hwInternalSleep loop.
     * Tested with atmega328p standalone but should work with Arduino Nano/Pro MiniCore
     * Uses RFM69 for transport.
     * Based on original work by:
     * Author: Patrick 'Anticimex' Fallberg
     * Connect one button or door/window reed switch between
     * digitial I/O pin 3 (BUTTON_PIN below) and GND and the other
     * one in similar fashion on digital I/O pin 2.
     * This example is designed to fit Arduino Nano/Pro Mini
    // Enable debug prints to serial monitor
    #define MY_DEBUG
    // Enable and select radio type attached
    //#define MY_RADIO_NRF24
    #define MY_RADIO_RFM69
    #define MY_RFM69_FREQUENCY RF69_433MHZ // Set your frequency here
    //#define MY_IS_RFM69HW // Omit if your RFM is not "H"
    //#define MY_RFM69_NETWORKID 100  // Default is 100 in lib. Uncomment it and set your preferred network id if needed
    #define MY_RF69_IRQ_PIN 2
    #define MY_RF69_IRQ_NUM 0
    #define MY_RF69_SPI_CS 10
    //#define MY_NODE_ID 2
    #include <MySensors.h>
    #define SKETCH_NAME "Binary Sensor"
    #define SKETCH_MAJOR_VER "2"
    #define SKETCH_MINOR_VER "0"
    #define PRIMARY_CHILD_ID 3 // PD3
    #define SECONDARY_CHILD_ID 4 // PD4
    #define PRIMARY_BUTTON_PIN 3   // Arduino Digital I/O pin for button/reed switch
    #define SECONDARY_BUTTON_PIN 4 // Arduino Digital I/O pin for button/reed switch
    #define DEBOUNCE_INTERVAL 100
    #define DEBOUNCE_COUNT_THRESHOLD 15 // required consecutive positive readings
    #define SLEEP_TIME (6 * 60 * 60 * 1000ul) // Check battery every 6 hours
    #define BATTERY_MAX_MVOLT 2900
    #define BATTERY_MIN_MVOLT 2300
    // Change to V_LIGHT if you use S_LIGHT in presentation below
    MyMessage msg(PRIMARY_CHILD_ID, V_LIGHT);
    MyMessage msg2(SECONDARY_CHILD_ID, V_LIGHT);
    bool triggered = false;
    uint32_t lastWakeup = 0;
    uint16_t lastBatteryVoltage = 0u;
    enum wakeup_t {
    volatile wakeup_t wakeupReason = UNDEFINED;
    // Pin change interrupt service routines
    ISR (PCINT0_vect) // handle pin change interrupt for PCINT[7:0]
      wakeupReason = WAKE_BY_PCINT0;
      _wokeUpByInterrupt = 0xFE; // Dirty hack to get out of MySensors sleep loop
    ISR (PCINT1_vect) // handle pin change interrupt for PCINT[14:8]
      wakeupReason = WAKE_BY_PCINT1;
      _wokeUpByInterrupt = 0xFE; // Dirty hack to get out of MySensors sleep loop
    ISR (PCINT2_vect) // handle pin change interrupt for PCINT[23:16]
      wakeupReason = WAKE_BY_PCINT2;
      _wokeUpByInterrupt = 0xFE; // Dirty hack to get out of MySensors sleep loop
    void pciSetup(byte pin)
      *digitalPinToPCMSK(pin) |= bit (digitalPinToPCMSKbit(pin));  // enable pin
      PCIFR  |= bit (digitalPinToPCICRbit(pin)); // clear any outstanding interrupt
      PCICR  |= bit (digitalPinToPCICRbit(pin)); // enable interrupt for the group
    void setup()
      // Workaround to use center frequency
      #ifdef MY_IS_RFM69HW
        _radio.setPowerLevel(16); // 10dBm for RFM69HW
        _radio.setPowerLevel(28); // 10dBm for RFM69W
      pinMode(PRIMARY_BUTTON_PIN, INPUT);           // set pin to input
      digitalWrite(PRIMARY_BUTTON_PIN, INPUT_PULLUP);       // turn on pullup resistors
      pinMode(SECONDARY_BUTTON_PIN, INPUT);           // set pin to input
      digitalWrite(SECONDARY_BUTTON_PIN, INPUT_PULLUP);       // turn on pullup resistors
      // Set up Pin change interrupt
    void presentation()
    	// Send the sketch version information to the gateway and Controller
    	// Register binary input sensor to sensor_node (they will be created as child devices)
    	// You can use S_DOOR, S_MOTION or S_LIGHT here depending on your usage.
    	// If S_LIGHT is used, remember to update variable type you send in. See "msg" above.
    	present(PRIMARY_CHILD_ID, S_LIGHT);
    void loop()
      // Unset value from dirty hack to get out of sleep loop (set in interrupt)
      _wokeUpByInterrupt = INVALID_INTERRUPT_NUM;
      CORE_DEBUG(PSTR("Woken up\n"));
      if(wakeupReason == WAKE_BY_PCINT2) {
        wakeupReason = UNDEFINED;
      CORE_DEBUG(PSTR("Going to sleep...\n"));
    void handleButtons()
      static uint8_t button1Count;
      static uint8_t button2Count;
      static uint32_t started, ended, delta;
      CORE_DEBUG(PSTR("Detecting buttons START\n"));
      button1Count = 0;
      button2Count = 0;
      // Try and detect which key during max DEBOUNCE_INTERVAL
      started = millis();
      while(millis() - started < DEBOUNCE_INTERVAL) {
        if(digitalRead(PRIMARY_BUTTON_PIN) == LOW) {
        } else {
        if(digitalRead(SECONDARY_CHILD_ID) == LOW) {
        } else {
        if(button1Count > DEBOUNCE_COUNT_THRESHOLD) {
          CORE_DEBUG(PSTR("Button 1 pressed\n"));
        if(button2Count > DEBOUNCE_COUNT_THRESHOLD) {
          CORE_DEBUG(PSTR("Button 2 pressed\n"));
      CORE_DEBUG(PSTR("Detecting buttons END\n"));
      // This section prevents detecting additional bounces
      ended = millis();
      if(ended > started) {
        delta = ended - started;
        if(delta < PREVENT_DOUBLE_INTERVAL) {
          CORE_DEBUG(PSTR("Waiting: %d \n"), PREVENT_DOUBLE_INTERVAL - delta);
          wait(PREVENT_DOUBLE_INTERVAL - delta); // In case the signal still is not stable after detection
    void handleBatteryLevel()
      static uint16_t voltage;
      static uint8_t batteryPct;
      CORE_DEBUG(PSTR("Checking Battery BEGIN\n"));
      voltage  = hwCPUVoltage();
      CORE_DEBUG(PSTR("Voltage: %d\n"), voltage);
      // Process change in battery level
      if(lastBatteryVoltage == 0 || lastBatteryVoltage != voltage) {
        lastBatteryVoltage = voltage;
        if(voltage < BATTERY_MIN_MVOLT) {
          batteryPct = 0;
        } else {
          batteryPct = 100 * (voltage - BATTERY_MIN_MVOLT) / (BATTERY_MAX_MVOLT - BATTERY_MIN_MVOLT);
      } else {
        CORE_DEBUG(PSTR("No Change\n"));
      CORE_DEBUG(PSTR("Checking Battery END\n"));

  • Well I've had some success on my own. There's another thread from January where I've discussed a little bit withe the MySensors team.
    Your dirty hack is beautiful in it's simplicity! 🙂 I have been roving a round in the library files and wound up in MyHWAVR.cpp to change a little bit. And I think I have found a way which is also simple. But I have to offer the change up for review to have it incorporated in a future version of MySensors. Only downside that it's tied to AVR for now. Needs testing to get it going on SAMD as well probably.
    For my tests I have been using the enableInterrupt library by the way. Found no trouble using that. And I have a little RC network on my switches to suppress bounce. Checked that on a scope and that worked like a charm.

    Keep you posted!

  • @DavidZH Any place where I can see your proposed changes? I am using @freynder 's approach but would like something more portable for future use.

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