Introduction: Power Saving Ultrasonic Switch
This is a prototype switch that automatically switches off any appliance that you have connected to your relay being a 2 way up to a 10 way relay for this specific one i am using a 2 way relay and will only be showing how to build the switch NOT CONNECT IT as it is very straight forward, this prototype also save enormous amount of electricity for obvious reasons.
Step 1: First Gather Parts
1. arduino uno R3
2. (2) way relay, any will work
3. jumper cables
4. breadboard (not necessary but easier to work with)
5. HC-SR04 ultrasonic ping sensor
Step 2: Tools
All you need are
1. A to B arduino USB
2. Arduino programming software
3. Your hands
Step 3: Assembly
1. take 1 ground and 1 5v jumper cable from your arduino to your breadboard
2. connect the grounds and the vcc from the relay and the sensor to the grd and vcc rail on your breadboard
3. connect all of your relay channels to the breadboard and the to digital pin 10 on your arduino
4. connect the echo pin on the ultrasonic sensor to digital pin12
5. connect the trig pin on the sensor to digital pin13
6. done !!!
Step 4: Coding
Connect your arduino to your pc
make sure you have selected the right board
then upload this sketch
#define trigPin 13
#define echoPin 12
#define led 11
#define led2 10
void setup() {
Serial.begin (9600);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
pinMode(led, OUTPUT);
pinMode(led2, OUTPUT);
}
void loop() {
long duration, distance;
digitalWrite(trigPin, LOW); // Added this line
delayMicroseconds(2); // Added this line
digitalWrite(trigPin, HIGH);
// delayMicroseconds(1000); - Removed this line
delayMicroseconds(10); // Added this line
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
distance = (duration/2) / 29.1;
if (distance < 4) { // This is where the Relay On/Off happens
digitalWrite(led,HIGH); // Relay on
digitalWrite(led2,LOW);
}
else {
digitalWrite(led,LOW);
digitalWrite(led2,HIGH);
}
if (distance >= 200 || distance <= 200){
Serial.println("Out of range");
}
else {
Serial.print(distance);
Serial.println(" cm");
}
delay(5000);
}
Step 5: Testing
place this setup within a meter of your door and walk through after connecting the relays if you have any problems please feel free to contact me.

Participated in the
MAKE ENERGY: A US-Mexico Innovation Challenge
Comments
8 years ago on Introduction
Hi Jandre... Been trying to figure out on the hook up plus the code.
I'm ok with the hook up how do i get around with the code? After using your code i'm getting out of range all the way...
Anyways this will safe alot of money if we were to place it on electronics that is on for no reason... good idea...