Turn relay on from Bluetooth for certain amount of seconds - c++

Question

I am working on two way communication between arduino and android phone. Currently everything is working, however I have couple of issues I have been trying to solve recently.
How I can ignite ignition for 5 seconds? I mean if IgnitionPin is on HIGH, run it for 5 seconds then automatically turn off? There is an easy way with delay, but it will not work in my case as don't want any other delays to slow up my script.
I am using Arduino Uno. I want to start my Arduino with pin in OFF position. Why pin 10 always turns ON then shuts down, even with digitalWrite(IgnitionPin, HIGH); I have tried other pins and they work fine -> turned OFF on start.
SoftwareSerial BTserial(12,13);
char choice;
const int loopDelay = 50;
int IgnitionPin = 10;
const long ignitionInterval = 5000;
int ignitionState = HIGH;
unsigned long previousMillis = 0;
void setup()
{
BTserial.begin(115200);
digitalWrite(IgnitionPin, HIGH);
pinMode(IgnitionPin, OUTPUT);
}
void loop()
{
if (BTserial.available())
{
choice = BTserial.read();
}
if( choice == 'm' )
{
ignitionState = HIGH;
digitalWrite(IgnitionPin, ignitionState);
ignitionCountTime = millis();
}
if (ignitionCountTime - previousMillis >= ignitionInterval) {
previousMillis = ignitionCountTime;
if (ignitionState == HIGH)
{
ignitionState = LOW;
}
digitalWrite(IgnitionPin, ignitionState);
}
delay(loopDelay);
}
EDIT:
SoftwareSerial BTserial(12,13);
char choice;
const int loopDelay = 50;
int IgnitionPin = 10;
unsigned long startTime;
unsigned long ignitionInterval = 30000;
unsigned long ignitionCountTime = 0;
void setup()
{
BTserial.begin(115200);
digitalWrite(IgnitionPin, HIGH);
pinMode(IgnitionPin, OUTPUT);
}
void loop()
{
if (BTserial.available())
{
choice = BTserial.read();
}
if( choice == 'm' )
{
digitalWrite(IgnitionPin, HIGH);
ignitionCountTime = millis();
}
if (ignitionCountTime - startTime >= ignitionInterval)
{
digitalWrite(IgnitionPin, LOW);
}
delay(loopDelay);
}

Answer 1

#1
Use the TimerOne library or setup an ISR.
Run the ISR at, 5 times per second.
uint32_t timeout = 5 * 60;
uint8_t flag = 1;
digitalWrite (myPin, HIGH);
if (timeout && flag) {
timeout--;
} else {
digitalWrite (myPin, LOW);
flag = 0;
}
OR
by checking time elapsed since some specific point in time.
unsigned long startTime;
unsigned long interval = 60000;
const byte aPin = 13;
void setup()
{
pinMode(aPin, OUTPUT);
digitalWrite(aPin, HIGH);
}
void loop()
{
if (millis() - startTime >= interval)
{
digitalWrite(aPin, LOW);
}
}
EDIT
Arduino is a microcontroller, it can do only one thing at once.
SoftwareSerial BTserial(12,13);
char choice;
const int loopDelay = 50;
int IgnitionPin = 10;
uint32_t timeout = 5 * 60;
uint8_t flag = 0;
void setup()
{
BTserial.begin(115200);
pinMode(IgnitionPin, OUTPUT);
digitalWrite(IgnitionPin, LOW);
}
void loop()
{
if (BTserial.available())
{
choice = BTserial.read();
}
if (choice == "m")
{
timeout = 5 * 60; //modify this timeout.
flag = 1;
digitalWrite(IgnitionPin, HIGH);
}
else if ((timeout > 0) && (flag == 1))
{
timeout--;
}
else
{
digitalWrite(IgnitionPin, LOW);
flag = 0;
}
delay(loopDelay);
}
#2 - In setup you are running 'digitalWrite(IgnitionPin, HIGH);' this will make it high
just use pinMode(IgnitionPin, OUTPUT); for setting pin as output pin
void setup()
{
Serial.begin(115200);
Serial.println("Enter AT commands:");
BTserial.begin(115200);
sensors.begin();
// Set Pin as an output pin
pinMode(IgnitionPin, OUTPUT);
digitalWrite(IgnitionPin, LOW);
}
If you want IgnitionPin as LOW at each restart - use 'digitalWrite(IgnitionPin, LOW);' in setup() after pinMode call.