# 12/12 Led timer?

Could someone please give me a code to a 12/12 timer led lighting? im going to hook up leds around the house, I want it to turn on for 12 hours and off for 12 hours a day. Thanks!

Wouldnt a Walmart \$3 timer do as good a job?

Will you use a real-time clock?

Yes, Is there a code like this?

I need the code asap :( it will be not real time, it will just turn on in 12 hours and turn off in the other 12 hours

I'm confused. Your one reply seemed to indicate you'd use a real time clock, and then you say not real time. Wanna go for two out of three?

Anyhoo, this is pretty straightforward, have you given it a try yourself? Might be an educational experience you know.

I'm not sure you really need to bother with a microcontroller... couldn't you do the job with a 555 timer and some counter ICs? If you really want to use an arduino for this simple task, look up the millis() function and how it relates to keeping time.

100Grand: I need the code asap :( it will be not real time, it will just turn on in 12 hours and turn off in the other 12 hours

Indoor farming?

Simple example:

``````const unsigned long twelve_hours = 12*60*60*1000;
unsigned long elapsed;
bool light_state;

void loop()
{
if ( millis() - elapsed >= twelve_hours )
{
light_state = !light_state;
elapsed = millis();

print( light_state ? "Light enabled" : "Light disabled" );
}
}
``````

fungus:

100Grand: I need the code asap :( it will be not real time, it will just turn on in 12 hours and turn off in the other 12 hours

Indoor farming?

Yes, Indoor farming planning on growing tomatoes

guix: Simple example:

``````const unsigned long twelve_hours = 12*60*60*1000;
unsigned long elapsed;
bool light_state;
``````

void loop() {   if ( millis() - elapsed >= twelve_hours )   {     light_state = !light_state;     elapsed = millis();                 print( light_state ? "Light enabled" : "Light disabled" );   } }

I need this code here, But only for the light, Could you edit it for me in a way that only the light will work? And I just want to use flower mode. http://www.instructables.com/files/orig/FY8/6LS8/FV4LSLHL/FY86LS8FV4LSLHL.tmp thanks, And if you do good you may get a donation :)

anybody? is there a code like this? http://www.instructables.com/files/orig/FY8/6LS8/FV4LSLHL/FY86LS8FV4LSLHL.tmp

100Grand: I need this code here, But only for the light, Could you edit it for me in a way that only the light will work? And I just want to use flower mode.

Well if you remove everything but what is related to light and flowering, you will end up with a code similar to mine, :D

guix:

100Grand: I need this code here, But only for the light, Could you edit it for me in a way that only the light will work? And I just want to use flower mode.

Well if you remove everything but what is related to light and flowering, you will end up with a code similar to mine, :D

What about the pins on your code? And it would be only flowering mode...

``````/*
Blink
Turns on an LED on for one second, then off for one second, repeatedly.

This example code is in the public domain.
*/

// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;

// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(led, OUTPUT);
}

// the loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
delay(43200000);               // wait for 12 hours
digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
delay(43200000);               // wait for 12 hours
}
``````

This is a modied version of the very first arduino project, blink. it originally blinks an LED on pin 13. The only thing I did to change this program was to change the timing from 1 second, to 12 hours.

My guess is that you will need more than 40ma, so you will need to use transistors or relays to switch to higher current devices, but the code is still the same.

Honestly, i think the cheapo 24 hour switch thing like someone previously mentioned would be more appropriate.

Like the previous code example, this would only do the flowering lights, which is really all you need, the other room would be lighted 24/7, and not need anything to control that.

I would be interested to find out how well LEDs work for growing. Most setups that i have seen require their own service panel, lots of expensive lights that use crazy amounts of current, and enclosures with fans to keep the lights from heating everything too much.

How many LEDs are you using? Im guessing it must be thousands.

Hippynerd: ``` /*   Blink   Turns on an LED on for one second, then off for one second, repeatedly.

This example code is in the public domain. */

// Pin 13 has an LED connected on most Arduino boards. // give it a name: int led = 13;

// the setup routine runs once when you press reset: void setup() {                  // initialize the digital pin as an output.   pinMode(led, OUTPUT);    }

// the loop routine runs over and over again forever: void loop() {   digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)   delay(43200000);               // wait for 12 hours   digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW   delay(43200000);               // wait for 12 hours }

``````

This is a modied version of the very first arduino project, blink. it originally blinks an LED on pin 13. The only thing I did to change this program was to change the timing from 1 second, to 12 hours.

My guess is that you will need more than 40ma, so you will need to use transistors or relays to switch to higher current devices, but the code is still the same.

Honestly, i think the cheapo 24 hour switch thing like someone previously mentioned would be more appropriate.

Like the previous code example, this would only do the flowering lights, which is really all you need, the other room would be lighted 24/7, and not need anything to control that.

I would be interested to find out how well LEDs work for growing. Most setups that i have seen require their own service panel, lots of expensive lights that use crazy amounts of current, and enclosures with fans to keep the lights from heating everything too much.

How many LEDs are you using? Im guessing it must be thousands.
``````

Thanks so much! ive been looking for something JUST LIKE THIS!!! :D

Yer welcome buddy. Good luck.

Hippynerd: ``` /*   Blink   Turns on an LED on for one second, then off for one second, repeatedly.

This example code is in the public domain. */

// Pin 13 has an LED connected on most Arduino boards. // give it a name: int led = 13;

// the setup routine runs once when you press reset: void setup() {                  // initialize the digital pin as an output.   pinMode(led, OUTPUT);    }

// the loop routine runs over and over again forever: void loop() {   digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)   delay(43200000);               // wait for 12 hours   digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW   delay(43200000);               // wait for 12 hours }

``````

This is a modied version of the very first arduino project, blink. it originally blinks an LED on pin 13. The only thing I did to change this program was to change the timing from 1 second, to 12 hours.

My guess is that you will need more than 40ma, so you will need to use transistors or relays to switch to higher current devices, but the code is still the same.

Honestly, i think the cheapo 24 hour switch thing like someone previously mentioned would be more appropriate.

Like the previous code example, this would only do the flowering lights, which is really all you need, the other room would be lighted 24/7, and not need anything to control that.

I would be interested to find out how well LEDs work for growing. Most setups that i have seen require their own service panel, lots of expensive lights that use crazy amounts of current, and enclosures with fans to keep the lights from heating everything too much.

How many LEDs are you using? Im guessing it must be thousands.
``````

Im using about 30 leds would it be sufficient? lol just a test

its not bright enough how do I Fix this?

Im using this code with 30 leds but its not bright enough? I Dont have any more relays ect, If i put the brightness on a scale of 1 - 10 its 5, but when I hook it up to a 9v battery its bright :(

``````/*
Blink
Turns on an LED on for one second, then off for one second, repeatedly.

This example code is in the public domain.
*/

// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;

// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(led, OUTPUT);
}

// the loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
delay(43200000);               // wait for 12 hours
digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
delay(43200000);               // wait for 12 hours
}
``````