Using both the water flow sensor and GSM shield on pin 2 or another one


Im building a small circuit sending the flow rate to an online system, the flow is calculating correctly but when i add the gsm shield on top of the arduino the shield take over the 2nd pin, im wondering if there is a way of doing it.

im using this code for the flow rate

byte statusLed = 13;

byte sensorInterrupt = 0; byte sensorPin = 12;

// The hall-effect flow sensor outputs approximately 4.5 pulses per second per // litre/minute of flow. float calibrationFactor = 4.5;

volatile byte pulseCount;

float flowRate; unsigned int flowMilliLitres; unsigned long totalMilliLitres;

unsigned long oldTime;

void setup() {

// Initialize a serial connection for reporting values to the host Serial.begin(38400);

// Set up the status LED line as an output pinMode(statusLed, OUTPUT); digitalWrite(statusLed, HIGH); // We have an active-low LED attached

pinMode(sensorPin, INPUT); digitalWrite(sensorPin, HIGH);

pulseCount = 0; flowRate = 0.0; flowMilliLitres = 0; totalMilliLitres = 0; oldTime = 0;

attachInterrupt(sensorInterrupt, pulseCounter, FALLING); }

/** * Main program loop */ void loop() {

if((millis() - oldTime) > 1000) // Only process counters once per second { // Disable the interrupt while calculating flow rate and sending the value to // the host detachInterrupt(sensorInterrupt);

// Because this loop may not complete in exactly 1 second intervals we calculate // the number of milliseconds that have passed since the last execution and use // that to scale the output. We also apply the calibrationFactor to scale the output // based on the number of pulses per second per units of measure (litres/minute in // this case) coming from the sensor. flowRate = ((1000.0 / (millis() - oldTime)) * pulseCount) / calibrationFactor;

// Note the time this processing pass was executed. Note that because we've // disabled interrupts the millis() function won't actually be incrementing right // at this point, but it will still return the value it was set to just before // interrupts went away. oldTime = millis();

// 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 = (flowRate / 60) * 1000;

// Add the millilitres passed in this second to the cumulative total totalMilliLitres += flowMilliLitres;

unsigned int frac;

// Print the flow rate for this second in litres / minute Serial.print("Flow rate: "); Serial.print(int(flowRate)); // Print the integer part of the variable Serial.print("."); // Print the decimal point // Determine the fractional part. The 10 multiplier gives us 1 decimal place. frac = (flowRate - int(flowRate)) * 10; Serial.print(frac, DEC) ; // Print the fractional part of the variable Serial.print("L/min"); // Print the number of litres flowed in this second Serial.print(" Current Liquid Flowing: "); // Output separator Serial.print(flowMilliLitres); Serial.print("mL/Sec");

// Print the cumulative total of litres flowed since starting Serial.print(" Output Liquid Quantity: "); // Output separator Serial.print(totalMilliLitres); Serial.println("mL");

// Reset the pulse counter so we can start incrementing again pulseCount = 0;

// Enable the interrupt again now that we've finished sending output attachInterrupt(sensorInterrupt, pulseCounter, FALLING); } }

/* Insterrupt Service Routine */ void pulseCounter() { // Increment the pulse counter pulseCount++; }

Please add code tags around your code above (edit and fix it)

What are all the pins used by your shield? Pin 3 will Also support interrupts for example

when i add the gsm shield on top of the arduino the shield take over the 2nd pin

If that happens so you can do SoftwareSerial on pins 2 and 3, bend them so they don't make contact, and solder jumper wires onto them, and connect the wires to other pins.

Then, write to the manufacturer and tell them that they are idiots for trying to force you to do SoftwareSerial on the interrupt pins.

You could put the turbine on pin 3, but I bet that doesn't help much.

I'm surprised your GSM shield doesn't give you options for the pins

It sounds like you are wanting to use software serial for the GSM, which is never such a good idea anyway. You could use hardware serial instead and you should find jumpers to that effect.

Does your GSM [u]actually work[/u] on pins 2,3? I only ask that because mine uses pins 7,8 for software serial, and I think one GSM shield is much like another. Indeed I wouldn't think the GSM manufacturer would be so stupid as to hog pins 2,3.

@nick - have a look at the Arduino GSM shield info....

Indeed I wouldn't think the GSM manufacturer would be so stupid as to hog pins 2,3.

Nice fantasy you've got going there.


It's not just GSM shields. Try finding an XBee shield that doesn't require the use of either the hardware serial pins or the external interrupt pins.