Published December 6, 2020 © GPL3+

Drawer light detector

Device that lets you know if someone has gone into your drawer by using a photoresistor that sends data to another argon device.

IntermediateFull instructions provided4 hours293

Things used in this project

Hardware components

Breadboard (generic)

Particle Argon

Jumper wires (generic)

LED (generic)

Photo resistor

Resistor 10k ohm

USB-A to Micro-USB Cable

Hand tools and fabrication machines

Wire Stripper & Cutter, 18-10 AWG / 0.75-4mm² Capacity Wires

Story

It wouldn't be 2020 without a tragedy. Towards the end of our project our original plan quickly fell apart as our water level sensor snapped and we had to quickly come up with another problem to tackle. Our revised project is a mechanism that can signal another particle argon to tell you if your drawer has been opened. The device works by reading the analog value from the photoresistor and using that value to determine if the drawer is open or not. If the value is lower than our calculated threshold, then the device will not trigger. It has a LED connected to the photoresistor as a possible extra security measure, and also a check to see if the device is working properly. The D7 LED on the receiving argon stays on for 5 seconds and the data is logged into the events so you can see when someone opened your drawer if you missed the LED indicator. We took the readings from the photoresistor at different drawers around the house and determined the average highest success value for the device to work.

Code

int led1 = A5;
int led2 = D7;
double analogValue_dbl;
int photoresistor = A0;
float analogValue; 

void setup()  {

    pinMode(led1, OUTPUT);
    pinMode(led2, OUTPUT);
    pinMode(photoresistor, INPUT);

}

void loop() {
    analogValue = analogRead(photoresistor);


    if (analogValue < 8) {
        digitalWrite(led1, LOW);
        digitalWrite(led2, LOW);
    } else {
        digitalWrite(led1, HIGH);
        digitalWrite(led2, HIGH);

analogValue_dbl = analogValue;


Particle.publish("toggle-led", PRIVATE);
    }
}