Problem with optimizing power consumption

[vga]

Hi,

i´ve made a sensor with the following hardware:

Arduino Mini Pro 3,3v 8Mhz: removed regulator, removed power-LED
NRF24L01+ Tranceiver
Water-Flow Sensor

The Flow-Sensor works, but now i want to power it with a battery:
In measuring mode, the consumption is 19mA, when entering gw.sleep the power consumption of the Sensor reduces to 2mA.
(also if I disconnect the Flow Sensor, and only the Transceiver is connected to the Arduino, it is still 2mA)
Is there a way to optimize the power consumption more?
I´ve heard about 120uA in sleep mode?
Maybe the gw.sleep does not turn of the ADC, SPI, BOD, like the LowPower library?
BTW, when i try to include the LowPower library, the arduino IDE says, it is not possible to compile LowPower for Arduino Pro Mini.

Here is my code:

// Sleep Mode Libraries laden
#include <avr/sleep.h>
#include <avr/power.h> 

// MySensor Library hinzufügen
#include <SPI.h>
#include <MySensor.h> 

#define CHILD_ID 0   // Id of the sensor child


//Batteriestatus 
int BATTERY_SENSE_PIN = A0;  // select the input pin for the battery sense point
int oldBatteryPcnt = 0;


MySensor gw;
MyMessage flowMsg(CHILD_ID,V_FLOW);
MyMessage volumeMsg(CHILD_ID,V_VOLUME);

 
volatile int NbTopsFan; //measuring the rising edges of the signal
float Calc;                               
int hallsensor = 3;    //The pin location of the sensor

unsigned int flowMilliLitres;
unsigned int lastFlowVal;

long totalMilliLitres;
long lastTotalVal;
 
void rpm ()     //This is the function that the interupt calls 
{ 
  NbTopsFan++;  //This function measures the rising and falling edge of the hall effect sensors signal
} 

// The setup() method runs once, when the sketch starts
void setup() //
{ 

  // Start Gateway Kommunikation
  gw.begin();
  
  // Send the sketch version information to the gateway and Controller
  gw.sendSketchInfo("Water Flow Sensor", "1.0");     
  // Register all sensors to gw (they will be created as child devices)  
  gw.present(CHILD_ID, S_WATER);

  
  pinMode(hallsensor, INPUT); //initializes digital pin 2 as an input
  Serial.begin(115200); //This is the setup function where the serial port is initialised,
  attachInterrupt(1, rpm, RISING); //and the interrupt is attached 1 = Digital Pin 3!

  // Batteriestatus
  // use the 1.1 V internal reference
  #if defined(__AVR_ATmega2560__)
   analogReference(INTERNAL1V1);
  #else
   analogReference(INTERNAL);
  #endif
} 
// the loop() method runs over and over again,
// as long as the Arduino has power
void loop ()    
{
   
  NbTopsFan = 0;   //Set NbTops to 0 ready for calculations
  sei();      //Enables interrupts

 if(flowMilliLitres == 0){
    delay (500);
  
    gw.sleep(300000); 
  }
  
  delay (1000);   //Wait 1 second
  cli();      //Disable interrupts
  Calc = (NbTopsFan / 7.5); //(Pulse frequency) / 7.5Q, = flow rate in L/min 
  Serial.print (Calc); //Prints the number calculated above
  Serial.print (" L/min\r\n"); //Prints "L/min" and returns a  new line
  int val=(int)Calc;

  // Divide the flow rate in litres/minute by 60 to determine how many litres have
  // passed through the sensor in this 1 second interval, then multiply by 1000 to
  // convert to millilitres.
  flowMilliLitres = (Calc / 60) * 1000;
    
  // Add the millilitres passed in this second to the cumulative total
  totalMilliLitres += flowMilliLitres;

  // Print the number of litres flowed in this second
  Serial.print("  Current Liquid Flowing: ");             // Output separator
  Serial.print(flowMilliLitres);
  Serial.print("mL/Sec");
  if(lastFlowVal != flowMilliLitres){
    gw.send(flowMsg.set(flowMilliLitres));
    lastFlowVal = flowMilliLitres;
  }
  

  // Print the cumulative total of litres flowed since starting
  Serial.print("  Output Liquid Quantity: ");             // Output separator
  Serial.print(totalMilliLitres);
  Serial.println("mL"); 
  if(lastTotalVal != totalMilliLitres){
    gw.send(volumeMsg.set(totalMilliLitres));
    lastTotalVal = totalMilliLitres;
    //Starting at the first byte on the eeprom.   
    //EEPROMWritelong(address, totalMilliLitres);
  }


  // get the battery Voltage
   int sensorValue = analogRead(BATTERY_SENSE_PIN);
   #ifdef DEBUG
   Serial.println(sensorValue);
   #endif
   
   // 1M, 470K divider across battery and using internal ADC ref of 1.1V
   // Sense point is bypassed with 0.1 uF cap to reduce noise at that point
   // ((1e6+470e3)/470e3)*1.1 = Vmax = 3.44 Volts
   // 3.44/1023 = Volts per bit = 0.003363075
   float batteryV  = sensorValue * 0.003363075;
   int batteryPcnt = sensorValue / 10;

   #ifdef DEBUG
   Serial.print("Battery Voltage: ");
   Serial.print(batteryV);
   Serial.println(" V");

   Serial.print("Battery percent: ");
   Serial.print(batteryPcnt);
   Serial.println(" %");
   #endif
   gw.sendBatteryLevel(batteryPcnt);

    
  
}

Would be nice to get some tipps for reducing the power consumption more, thanks!

[Yveaux]

@vga did you try searching the forum first?
There are numerous topics on power consumption in sleep mode, containing many tips!

[vga]

yes, i used the search function, but there are no tips which are helpful for my problem.
While sleep mode, using gw.sleep, the power consumption is still 2mA.

[AWI]

@vga The gw.sleep() lets you go as low as 2uA so there must be something else in your circuit which still consumes.. Maybe (internal) pull-ups?

[vga]

@AWI you are right. My fault, I checked again my wiring. the flow sensor is connected to vcc, so it consumes permanently. disconnected and restarted the arduino, the consumption in sleep is 0,1mA.

so i tried to connect the flow sensor to a digital pin, set it to output mode and put it HIGH.
When it go to sleep i set it to LOW.

But I fail to see that it wake up again with interruptpin, when sensor change, but if it has no power, of course it can not change! :smirk:

any idea how to make the best of it?
timer interrupt is no alternative, cause of possible missing sensor activity.

[AWI]

@vga What kind of flow sensor are you using? If you could use a passive type (i.e. reed contact) that would make the difference..

[vga]

i am using this sensor:
http://www.seeedstudio.com/wiki/images/b/b7/Water_flow_sensor_datasheet.pdf
Do you know a "reed Sensor" for such a my sensor project?

[AWI]

@vga The sensor you are referring to is working with "hall" effect. I can't find the internal schematics of the thing but I assume there are some active components to give you a nice square wave output. Another principle would be a magnet with reed (magnetic) contact which you can read with minimal current.
You can find the " rest" current by measuring the power line of the sensor .