Eric Fossum / Mbed 2 deprecated SprinklerTimer

I needed a device to time my sprinklers, because I had been forgetting to turn them off. So I made a very simple program to turn them off after 45 minutes. Future versions will have an array of outputs, so you can run sections with one button push. Hardware: Either board should work, I used the LPC1768. You will also need a solenoid to control the water, I am testing a 12V rainbird valve with a relay and 12V power supply.

Dependencies:   PinDetect mbed

Sprinkler Timer

I needed a device to time my sprinklers, because I had been forgetting to turn them off. So I made a very simple program to turn them off after some number of minutes.

Hardware

• Tested on the LPC1768
  • Either board should work
• You will also need some way of controlling the flow of water (like a solenoid valve and a relay). My test equipment:
  • 12V Rainbird valve (Rain Bird 3/4-Inch Sprinkler System Automatic In-Line Valve)
  • relay (SainSmart 2 channel relay)
  • 12V power supply (Replacement LCD Monitor Ac Adapter 12v 5a)
• Some Button for start/stop
• Some way of powering the board (maybe someone can help me power it from the 12v supply)

Connections

Button:

• One side to pin 5
• the other to Vout

Relay:

• Vcc to Vout
• Gnd to ground
• IN1 to pin 6

Directions/Use

• The button will start the sprinkler when it is off and vice versa.
• Once started if not interrupted, the sprinkler shall run for 25 minutes.

Future

Future versions will have an array of outputs, so you can run sections with one button push.

#include "mbed.h"
#include "PinDetect.h"

// Objects
DigitalOut myLed(LED1);
DigitalOut solenoid(p6);
PinDetect button(p5);
Timer timer;

// Primitives
int timeInMinutes = 25; // Timer is only good to about 30 mins!
float halfSecond = 0.5; // LED blink rate

// Interrupt function for start/stop button
//////////////////////////////////////////////////
void StartStop() {
    // Enabled = !Enabled
    if(solenoid.read()) {
        // Turn off
        timer.stop();
        solenoid = false;
    } else {
        // Turn on
        timer.reset();
        timer.start();
        solenoid = true;
    }
}

// Main loop
//////////////////////////////////////////////////
int main() {
    // Set button interrupt w/PullDown and debounce
    button.mode(PullDown);
    button.attach_asserted_held(&StartStop);
    button.setSampleFrequency(9);
    
    // Infinite loop
    while(true) {
        // Stop if time(s) > n Mins(m) * 60(s)
        if(timer.read() > timeInMinutes * 60) {
            solenoid = false;
            timer.stop();
        }
        
        // Slow pulse status LED when enabled
        if(solenoid.read())
            myLed = !myLed.read();
        else
            myLed = false;
        
        // Wait so LED pulses
        wait(halfSecond);
    }
}