Hello currently trying to make a motion sensor light that i can turn on and off with sensor detection but also have auto turn off after lets say 15 minutes if left on. I've got it so i can turn it off and on now using motion but not sure how to have it auto turn off after a set time since delay blocks me from turning it off with motion if i try using that. I'm thinking I'll have to use the millis function? but not sure where to start and feel like I've hit a wall so any guidance would be appreciated. here's the code i have so far to have the sensor turn it off and on. int led = 8; int pir = 2; int val; int state = 0; void setup() { pinMode(led, OUTPUT); pinMode(pir, INPUT); } void loop() { val = digitalRead(pir); if (val == HIGH) { if (state == 0) { state = 1; digitalWrite(led, HIGH); delay (4000); } else { state = 0; digitalWrite(led, LOW); delay (4000); } } }

When sensor detects the turn on state, you enable a timing flag and start the TIMER. The operative word is when. If you manually turn off the light, disable the flag. When the flag is enabled the TIMER is checked to see if the interval has been reached, if so, turn off the light. if(flag == enabled && millis() - startTime >= (15 * 60 *1000ul)) { // turn off the light flag = disabled; }

how exactly do i go about implementing this into what i already have? I've tried for a while now but don't seem to be getting anywhere sorry. i can't seem to be able to get my thick skull around millis no matter how hard i try.

Show us the sketch you tried. In the Arduino IDE, use Ctrl T or CMD T to format your code then copy the complete sketch. Use the icon from the ‘reply menu’ to attach the copied sketch.

this old version is all i have now unfortunately, but it'll show you what i think i was trying to do? still quite new to this so it's probably embarrassingly far from right. int led = 8; int pir = 2; int val; int state = 0; unsigned long sleep_start; unsigned long previousMillis = 0; void setup() { pinMode(led, OUTPUT); pinMode(pir, INPUT); } void loop() { unsigned long currentMillis = millis(); val = digitalRead(pir); if (sleep_start > 0 && millis() > sleep_start + 15 * 60 * 1000) if (val == HIGH) { if (state == 0) { state = 1; digitalWrite(led, HIGH); sleep_start = millis(); delay (4000); } else { state = 0; sleep_start = 0; digitalWrite(led, LOW); delay (4000); } } }

[image] bobbycarry: currently trying to make a motion sensor light that i can turn on and off with sensor detection but also have auto turn off after lets say 15 minutes if left on. Is this what you had in mind ? // Version YY/MM/DD Description // 1.00 21/07/03 Functional code // 1.01 21/07/03 Added comments //********************************************************************* #define movementDetection HIGH #define LEDon HIGH #define LEDoff LOW #define enabled true #define disabled false //********************************************************************* const byte heartbeatLED = 13; const byte led = 8; const byte pir = 2; bool autoOffFlag = disabled; byte lastPIRstate = !movementDetection; byte val; byte state = 0; //Timing stuff const unsigned long timeoutDuration = 5000; //5 seconds for testing //const unsigned long timeoutDuration = 15 * 60 * 1000ul; //15 minutes unsigned long heartbeatMillis; unsigned long switchMillis; unsigned long autoMillis; //********************************************************************* void setup() { pinMode(heartbeatLED, OUTPUT); //turn the light OFF digitalWrite(led, LEDoff); pinMode(led, OUTPUT); pinMode(pir, INPUT); } //END of setup() //********************************************************************* void loop() { //*********************** //time to toggle the heartbeatLED ? if (millis() - heartbeatMillis >= 500) { //restart the TIMER heartbeatMillis = millis(); //toggle the LED digitalWrite(heartbeatLED, !digitalRead(heartbeatLED)); } //*********************** //time to check the switches ? if (millis() - switchMillis >= 50) { //restart the TIMER switchMillis = millis(); checkSwitches(); } //*********************** //if enabled, has the auto timout duration be reached ? if (autoOffFlag == enabled && millis() - autoMillis >= timeoutDuration) { //disable the TIMER autoOffFlag = disabled; //turn the light OFF digitalWrite(led, LEDoff); } } //END of loop() //********************************************************************* void checkSwitches() { //***************************************** PIR // byte state = digitalRead(pir); //*********************** //has the PIR changed state ? if (lastPIRstate != state) { //update to the new state lastPIRstate = state; //************ //has the PIR detected movement ? if (state == movementDetection) { //enable the TIMER autoOffFlag = enabled; //start the TIMER autoMillis = millis(); //turn ON the light digitalWrite(led, LEDon); } //PIR sensor must have timed out else { //disable the TIMER autoOffFlag = disabled; //turn OFF the light digitalWrite(led, LEDoff); } } //END of if (lastPIRstate != state) } //END of checkSwitches() //*********************************************************************

not entirely sure to be honest, tried to change the times on that code to stay on but couldn't keep it on for more then a few seconds, i think the sensor stays active for 3-4 seconds after activation so not sure if that could have something to do with it?

If the sensor detects movement are you saying it sends a HIGH (+5v) to the Arduino input ? This HIGH lasts for at least 3-4 seconds by an internal timer in the sensor ?

i believe so, that's why at first i was just using delay as a way to wait for the sensor to finish before i started checking for movement again but ran into the problem of figuring out an auto time off as well. sorry I'm a bit of a newbie at this, it's my first Arduino project

It is very important that the following be confirmed: the PIR sends a HIGH (+5v) to the Arduino input when the PIR detects movement (use a DVM to confirm) OR does the sensor just close a dry relay contact ? if movement is detected every 1 second will the PIR signal to the Arduino ever time out ? if there was constant movement for 2 minutes then all movement stops completely, when would you like the LED to turn OFF ?

Motion Sensor Light timer

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anon21599558 July 4, 2021, 12:39am 2

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Motion Sensor Light timer

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