TouchSensor Sleep+Wakeup

Other Hardware Sensors
1

Hello so I'm about 75% there (I Think) I have a touchsensor connected to pin 2 and the standard ground and % volt connected to the arduino uno. My question is when I start the code it runs the function "Wakeupnow" fine and when I touch the sensor it puts the arduino to sleep perfectly fine. The issue i'm running is when I wake the arduino back up it runs "wakeupnow" once then goes immediately to the Loop() function then goes right back to sleep.

Anyway I can have it so when it wake up it runs the wakeupNow() function only without going immediatly to the second function (Loop() ) which puts it back to sleep? Here is the code

#include <avr/sleep.h>

int wakePin = 2; // pin used for waking up

void wakeUpNow() // here the interrupt is handled after wakeup
{
Serial.println("running code");
delay(100);
}

void setup()
{
Serial.begin(9600);
pinMode(wakePin, INPUT);
Serial.begin(9600);
attachInterrupt(0, wakeUpNow, LOW); // use interrupt 0 (pin 2) and run function
digitalWrite(led, HIGH);
delay(100);
digitalWrite(buzzer, LOW);
digitalWrite(led, LOW);
}

void loop()
{
Serial.println("work");
delay(1000);
sleepNow();
}

void sleepNow() // here we put the arduino to sleep
{
Serial.println("sleep");
delay(200);
set_sleep_mode(SLEEP_MODE_PWR_DOWN); // sleep mode is set here
sleep_enable(); // enables the sleep bit in the mcucr register
attachInterrupt(0,wakeUpNow, RISING); // use interrupt 0 (pin 2) and run function
sleep_mode(); // here the device is actually put to sleep!!
sleep_disable(); // first thing after waking from sleep:
wakeUpNow();
detachInterrupt(0); // disables interrupt 0 on pin 2 so the
}
2

The Arduino will run loop() all the time, it's supposed to run loop() all the time. This code will put it to sleep about a second after you start up the device, whether you touch the sensor or not.

Solution: have your ISR (wakeUpNow()) set a flag, indicating you want to go to sleep. Then have loop() react to that flag.

And another thing: DON'T try to print from an ISR. That is not sure to work, and generally a bad thing to do from an ISR. Set a flag here and have loop() do the print() command based on it.

Don't forget to set all global variables that the ISR writes to as volatile.

3

Thank you for your replay I truly appreciate it. So I modified it where it is behaving a lot better. The main goal here is to run off a battery and have the arduino turn itself off and on with the button. Would this serve to put the arduino to sleep effieciently?

#include <avr/sleep.h>
#include <SoftwareSerial.h>
#include <DFPlayer_Mini_Mp3.h>

const int buttonPin = 2;     // the number of the pushbutton pin
boolean buttonWasLow = false;         // variable flag for when the pushbutton goes low

//int wakePin = 2; // pin used for waking up
SoftwareSerial mySerial(9, 10); // RX, TX

void wakeUpNow() // here the interrupt is handled after wakeup
{
 Serial.println("waking up now");
}

void setup(){
Serial.begin(9600);
//pinMode(wakePin, INPUT);
mySerial.begin (9600);
pinMode(buttonPin, INPUT);    // initialize the pushbutton pin as an input:
mp3_set_serial (mySerial);  //set softwareSerial for DFPlayer-mini mp3 module 
mp3_set_volume (30); 
delay(100);
}

void loop()
{
    // read the state of the pushbutton and set a flag if it is low:
    if (digitalRead(buttonPin) == LOW)  {
        buttonWasLow = true;
        wakeUpNow();
    }

    // This if statement will only fire on the rising edge of the button input
    if (digitalRead(buttonPin) == HIGH && buttonWasLow)  {
        // reset the button low flag
        buttonWasLow = false;
        sleepNow();
    }
}

void sleepNow() // here we put the arduino to sleep
{
Serial.println("sleeping now");
delay(200);
set_sleep_mode(SLEEP_MODE_PWR_DOWN); // sleep mode is set here
sleep_enable(); // enables the sleep bit in the mcucr register
attachInterrupt(0,wakeUpNow, RISING); // use interrupt 0 (pin 2) and run function
sleep_mode(); // here the device is actually put to sleep!!
sleep_disable(); // first thing after waking from sleep:
wakeUpNow();
detachInterrupt(0); // disables interrupt 0 on pin 2 so the
}
4

I'd have to consult the docs on Arduino's sleep.

More consideration:

  • LEDs that are still lit.
  • you don't put the mp3 player to sleep (I think it has a sleep mode).
  • check the power consumption of the touch sensor itself - by nature they're active sensors, or they can't sense the touch.