In this article we learn how to make a simple 2-step Arduino programmable timer circuit, which can be used to switch an electrical load ON/OFF with independently adjustable ON and OFF timings.
For example if you want a light to remain ON for 24 hours and OFF for 2 hours, you can simply do this through a quick modification in the program code. In the same way you can customize the output timings to any other desired set of time intervals by changing the code appropriately.
You just have to compile and upload the following code to your Arduino board and start the timer function as per your specific application needs.
Program Code
void setup(){
pinMode(13, OUTPUT);
}
void loop(){
digitalWrite(13, HIGH);
delay(86400000);
digitalWrite(13, LOW);
delay(3600000);
}In the above example code the lines delay(86400000); and delay(3600000); determine the output ON and OFF delay time intervals respectively, in milliseconds. Here, the figure 86400000 milliseconds corresponds to 24 hours, while 3600000 exhibits 1 hour delay.
You can customize these two values as per your personal preference to get the required output delays.
Once setup and powered, the Arduino will continue switching between the two step ON/OFF timing sequence. as long as power remains applied to the system.
Circuit Diagram
The complete circuit diagram along with the Arduino connections can be witnessed in the following diagram:
Arduino One-Shot Timer Circuit
If you don't want the timer to loop through the two step timer, instead want the timer to be a one-shot type, which will switch OFF permanently after the set delay, you can apply the following code:
int led = 13; // Pin 13 has an LED connected on most Arduino boards.
unsigned long DELAY_TIME = 10000; // 10 sec
unsigned long delayStart = 0; // the time the delay started
bool delayRunning = false; // true if still waiting for delay to finish
void setup() {
pinMode(led, OUTPUT); // initialize the digital pin as an output.
digitalWrite(led, HIGH); // turn led on
// start delay
delayStart = millis();
delayRunning = true;
}
void loop() {
// check if delay has timed out
if (delayRunning && ((millis() - delayStart) >= DELAY_TIME)) {
delayRunning = false; // finished delay -- single shot, once only
digitalWrite(led, LOW); // turn led off
}
}If you want a discretely designed version of an identical programmable timer circuit, you can opt for this circuit
Parts Required for the Arduino Programmable Timer Circuit
- Arduino UNO Board = 1
- IC 7809 = 1
- BC547 = 1
- 1N4007 Diode = 1
- 10k 1/4 w resistor = 1
- Relay 12V/400 ohm/SPDT/5 amp = 1
- 12V AC to DC Adapter = 1
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Hello, sorry if this may seem off topick, am trying to make a inverter using arduino uno, am not good in cording so i generated a code from an android app, the inverter seem to be working ok, the only problem i have is how to give it feedback so the output voltage can be stable.
below is the generated code
#include
#define HO1 12
#define LO1 11
#define HO2 10
#define LO2 9
int f_sin=50;
int f_pwm=10000;
float sin_buffer[200];
float sampling_tot,pwm_period,sin_period,us=1000000;
int count=0,flag=0,Ampli=1000;
void setup() {
Serial.begin(9600);
pinMode(HO1,OUTPUT);
pinMode(LO1,OUTPUT);
pwm_period=(us*1)/f_pwm;
sin_period=(us*1)/f_sin;
sampling_tot=(sin_period/pwm_period)/2.0;
Serial.println(pwm_period);
Serial.println(sin_period);
Serial.println(sampling_tot);
for(int deg=0;deg(sampling_tot) && flag==1 ){
flag=0;
count=1;
TCCR1A=0b10110000;
}
if(count>(sampling_tot) && flag==0 ){
flag=1;
count=1;
TCCR1A=0b11100000;
}
count++;
if(flag==0){
Timer1.pwm(HO2,sin_buffer[count]* Ampli);
Timer1.pwm(LO2,sin_buffer[count]* Ampli);
digitalWrite(HO1,HIGH);
digitalWrite(LO1,LOW);
}
if(flag==1){
Timer1.pwm(HO2,sin_buffer[count]* Ampli);
Timer1.pwm(LO2,sin_buffer[count]* Ampli);
digitalWrite(HO1,LOW);
digitalWrite(LO1,HIGH);
}
}
Hello, if the inverter is working that means the code should be fine too…sorry, just like you I am too not good with coding stuff, so won’t be able to help you much in this regard.
Good day sir…happy Sunday…please I want be familiarize with arduino system..please help..how do I give a command it or program it? Thanks Engr.
Hello Sunshine, You can read the following article to get some basic tips regarding Arduino programming:
Learning Basic Arduino Programming – Tutorial for the Newcomers
Dear Sir;
I am in need of Arduino controlled reverse and forward relay controlled project details.
Following are the steps:-
1. After power ON, only after pushing ON push button (PB1), after 15 seconds, both relay1 (Motor1) and relay2 (Motor2) will start automatically simultaneously and stopped simultaneously, by pushing OFF push button (PB2) .
2. Relay3 (Motor3) will remain stopped, unless and until we press direction change push button (PB3).
3. When we will press PB3, relay2 stops and relay3 will ON after a timing gap of 15 seconds. Both relay2 and relay3 are interlocked. And stopped through PB2.
4. Along with PB3, there is also provision for a proximity switch (PB3 OR proximity switch) to change direction as per step number 3.
5. All three relay1, relay2 and relay3 will start with PB1 and stopped with PB2.
6. Relay1 is controlled with PB1 and PB2 only.
Thanks in advance for your kind guidance and support.
Sanjiv Mohbansi
sbmohbansi@gmail.com
Dear Sanjiv, I am not good with Arduino coding, so won’t be able to help you with this project.
Thank you Sir for your kind reply!!
Else as per your view, is there any option without using Arduino??
Awaiting your suggestion.
Thanks in advance!!
Yes it is possible using a simple flip flop circuit
Please Sir can you elaborate on how to load a bootloader to ATMEGA 328?
Thank you
Sorry Dan, I have no idea about it.
Thank you very much Sir for your quick responds. its exactly what I need.
You are welcome Dan!
wow Thanks a lot Swagatam the code (sketch) is working very well.
Glad it’s working Dan, hope you succeed with the project.