I have a brass valve flow meter connected to a Nano with bluetooth transmitting to a mobile ios app.
Currently the code transmits data in real time but I'd like to make sure I have the last data saved in case the unit hangs or something. I'm wondering how to go about that?
Here is the code:
/*
Liquid flow rate sensor -DIYhacking.com Arvind Sanjeev
Measure the liquid/water flow rate using this code.
Connect Vcc and Gnd of sensor to arduino, and the
signal line to arduino digital pin 2.
*/
//BLE
//include <SPI.h> and <ble.h>
//setup()SPI.setDataMode,setBitOrder, setClockDivider, begin(), ble_begin
//ifble_connected() while ble_available(), ble_read() or ble_write()
byte statusLed = 13;
byte sensorInterrupt = 0; // 0 = digital pin 2
byte sensorPin = 2;
// The hall-effect flow sensor outputs approx 4.5 pulses/sec/litre/min 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(115200);
// 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;
// The Hall-effect sensor is connected to pin 2 which uses interrupt 0.
// Configure to trigger on a FALLING state change (transition from HIGH
// state to LOW state)
attachInterrupt(sensorInterrupt, pulseCounter, FALLING);
}
/**
* Main program loop
*/
void loop(){
if((millis() - oldTime) > 5000) { // 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");
//Send data over BLE
sendOverBLE();
// 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++;
}
///////ble send
void sendOverBLE() {
int mystring;
mystring = int(totalMilliLitres);
// if (Serial.available() > 0) {
// Serial.println(mystring);//send what has been received
// Serial.println(); //print line feed character
// }
Serial.println(mystring);//send what has been received
Serial.println(); //print line feed character
//Sometimes I get null in the BlunoTerminal ap and I must open the Serial Monitor
//in order to get the valid data across...How would I do this in the app?
//Serial.flush();
}