![\"night-security-light-gif\"](\"https:\/\/i0.wp.com\/rntlab.com\/wp-content\/uploads\/2016\/11\/Night-Security-Light-GIF.gif?resize=480%2C270&quality=100&strip=all&ssl=1\")
<\/p>\nIn this project you\u2019re going to build a night security light with a relay module, a photoresistor and an Arduino.<\/p>\n
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A night security light only\u00a0turns on when it’s dark and when\u00a0movement is detected.<\/p>\n
Here\u2019s the main features of this project:<\/p>\n
The following resources include guides on how to use\u00a0the relay module and the PIR motion sensor with the Arduino, which might be useful for this project.<\/p>\n
Here\u2019s a complete list of the parts required for this project:<\/p>\n
![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/06\/Parts-required.jpg?resize=700%2C460&quality=100&strip=all&ssl=1\")
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Besides these electronics components, you also need an AC male socket, an AC wire and a lamp bulb holder (a lamp cord set). My lamp cord set is the one in the figure below.<\/p>\n
![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/06\/lamp-cord-set.jpg?resize=700%2C418&quality=100&strip=all&ssl=1\")
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You can use the preceding links or go directly to MakerAdvisor.com\/tools<\/a> to find all the parts for your projects at the best price!<\/p> Download or copy the following\u00a0code to your Arduino IDE, and upload it to your Arduino board.<\/p>\n Warning:<\/span> do not upload a new code to your Arduino board while your lamp is\u00a0connected to the\u00a0mains voltage. You should unplug the lamp from mains voltage, before upload a new sketch to your Arduino.<\/strong><\/p>\n View raw code<\/a><\/p>\n Here\u2019s the schematics for this project.<\/p>\n![](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/10\/header-200.png?w=1200&quality=100&strip=all&ssl=1\")
<\/a><\/p>\nCode<\/h2>\n
\/*\n * Rui Santos \n * Complete Project Details http:\/\/randomnerdtutorials.com\n *\/\n \n\/\/ Relay pin is controlled with D8. The active wire is connected to Normally Closed and common\nint relay = 8;\nvolatile byte relayState = LOW;\n\n\/\/ PIR Motion Sensor is connected to D2.\nint PIRInterrupt = 2;\n\n\/\/ LDR pin is connected to Analog 0\nint LDRPin = A0;\n\/\/ LDR value is stored on LDR reading\nint LDRReading;\n\/\/ LDR Threshold value\nint LDRThreshold = 300;\n\n\/\/ Timer Variables\nlong lastDebounceTime = 0; \nlong debounceDelay = 10000;\n\nvoid setup() {\n \/\/ Pin for relay module set as output\n pinMode(relay, OUTPUT);\n digitalWrite(relay, HIGH);\n \/\/ PIR motion sensor set as an input\n pinMode(PIRInterrupt, INPUT);\n \/\/ Triggers detectMotion function on rising mode to turn the relay on, if the condition is met\n attachInterrupt(digitalPinToInterrupt(PIRInterrupt), detectMotion, RISING);\n \/\/ Serial communication for debugging purposes\n Serial.begin(9600);\n}\n\nvoid loop() {\n \/\/ If 10 seconds have passed, the relay is turned off\n if((millis() - lastDebounceTime) > debounceDelay && relayState == HIGH){\n digitalWrite(relay, HIGH);\n relayState = LOW;\n Serial.println("OFF");\n }\n delay(50);\n}\n\nvoid detectMotion() {\n Serial.println("Motion");\n LDRReading = analogRead(LDRPin);\n \/\/ LDR Reading value is printed on serial monitor, useful to get your LDRThreshold\n \/\/Serial.println(LDRReading);\n \/\/ Only turns the Relay on if the LDR reading is higher than the LDRThreshold\n if(LDRReading > LDRThreshold){\n if(relayState == LOW){\n digitalWrite(relay, LOW);\n }\n relayState = HIGH; \n Serial.println("ON");\n lastDebounceTime = millis();\n }\n}\n<\/code><\/pre>\n\tSchematics<\/h2>\n
![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2016\/11\/warning-m-1.png?resize=700%2C200&quality=100&strip=all&ssl=1\")
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![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/06\/Schematics_f.png?resize=700%2C448&quality=100&strip=all&ssl=1\")
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