The idea has been slightly changed since I installed a LED tape on my kitchen counter, but there are other places in the house where to use this project.
In order to start slow and getting things done, I decided to build an Arduino prototype first. Then I'll try bit by bit to alter the configuration to avoid using an IC (if possible).
This project is the use of a motion sensor and an LDR to light up some LEDs when I pass by the sensors at night.
I already wrote about the PIR Motion Sensor and the LDR on previous posts.
Now it's time to use them together.
The PIR Motion Sensor needs 6 to 12V to work correctly because it has an in-built 5V regulator. As I intend to use it with an Arduino or with an external regulator for the whole circuit, I decided to bypass that internal regulator.
I read on Sparkfun's forums that some people had no problems from doing that simple bypass, and it looks safe enough, so I managed to it with some clumsy soldering:
I connected the sensors like on the previous posts and added a couple of pots to control LDR sensitivity and on time for the LED. Looks a mess, but it's quite simple.
Here are the schematics for a better understanding:
And of course, all this needs some Arduino code:
void setup() {
pinMode(2, INPUT);
pinMode(5, OUTPUT);
Serial.begin(9600);
}
//int sample = 0;
void loop() {
// LDR value: the bigger the value, the darker the room
// mapping the LDR input to correspond to a valid PWM value
int m = map(analogRead(A1), 0, 1023, 0, 255);
// PIR value: when motion is detected turns LOW, else HIGH
int v = digitalRead(2);
// Sensitivity pot
int p = map(analogRead(A0), 0, 1023, 0, 255);
// Time pot
int t = map(analogRead(A2), 0, 1023, 1000, 10000);
if( m > p && v == LOW )
{
digitalWrite(5, HIGH);
delay(t);
}
else
digitalWrite(5, LOW);
// Writes to serial only 1 in 5 turns
/*if(sample % 5 == 0)
{
Serial.print("LDR: ");
Serial.print(m);
Serial.print(" Sense: ");
Serial.print(p);
Serial.print(" PIR: ");
Serial.print(v);
Serial.print(" Time: ");
Serial.println(t);
}*/
delay(50);
// Avoid overflow
/*if(sample == 10000)
sample = 0;
sample++;*/
}
