Hello guys! In this instructable I'll teach you how to make a very simple proximity sensor using infrared LEDs and Arduino.
After several times trying to optimize it, I finally came up with something that is quite simple e precise. Just like my first instructable, this project is perfect for beginners in the arduino's world, with a few components anyone can make it. I hope you all enjoy it.
After several times trying to optimize it, I finally came up with something that is quite simple e precise. Just like my first instructable, this project is perfect for beginners in the arduino's world, with a few components anyone can make it. I hope you all enjoy it.
Step 1: Materials
For this instructable you are gonna need:
- Arduino
- 1 IR LED receiver (photodiode with 2 pins, not the phototransistor with 3 pins)
- IR LED emitters (as much as you can get, but at least 2)
- 100K resistor (brown black yellow)
- Jumper wires
- Breadboard
- Electrical tape
- Buzzer(optional)
Be careful to don't mix up the LED receiver with the LED emitter, they all look the same.
- Arduino
- 1 IR LED receiver (photodiode with 2 pins, not the phototransistor with 3 pins)
- IR LED emitters (as much as you can get, but at least 2)
- 100K resistor (brown black yellow)
- Jumper wires
- Breadboard
- Electrical tape
- Buzzer(optional)
Be careful to don't mix up the LED receiver with the LED emitter, they all look the same.
Step 2: Preparing the sensor
Before mount it, we should prepare the IR LED receiver to don't receive light from the sides, so than the sensor is more directional.
I use electrical tape to make it, but you can use a straw or anything that blocks the light from the sides.
Cut a small piece of electrical tape and wrap it around the IR LED receiver, forming a tube. Trim the edge with a pair of scissors until it's about 1cm long.
Have a look at images to see how I made it with electrical tape.
I use electrical tape to make it, but you can use a straw or anything that blocks the light from the sides.
Cut a small piece of electrical tape and wrap it around the IR LED receiver, forming a tube. Trim the edge with a pair of scissors until it's about 1cm long.
Have a look at images to see how I made it with electrical tape.
Step 3: Code time!
Write the code above on the Arduino program and upload it to the Arduino.
I also added an buzzer to this project if you wanna "hear" the distance.
// Simple Proximity Sensor using Infrared
// Description: Measure the distance to an obstacle using infrared light emitted by IR LED and
// read the value with a IR photodiode. The accuracy is not perfect, but works great
// with minor projects.
// Author: Ricardo Ouvina
// Date: 01/10/2012
// Version: 1.0
int IRpin = A0; // IR photodiode on analog pin A0
int IRemitter = 2; // IR emitter LED on digital pin 2
int ambientIR; // variable to store the IR coming from the ambient
int obstacleIR; // variable to store the IR coming from the object
int value[10]; // variable to store the IR values
int distance; // variable that will tell if there is an obstacle or not
void setup(){
Serial.begin(9600); // initializing Serial monitor
pinMode(IRemitter,OUTPUT); // IR emitter LED on digital pin 2
digitalWrite(IRemitter,LOW);// setup IR LED as off
pinMode(11,OUTPUT); // buzzer in digital pin 11
}
void loop(){
distance = readIR(5); // calling the function that will read the distance and passing the "accuracy" to it
Serial.println(distance); // writing the read value on Serial monitor
// buzzer(); // uncomment to activate the buzzer function
}
int readIR(int times){
for(int x=0;x<times;x++){
digitalWrite(IRemitter,LOW); // turning the IR LEDs off to read the IR coming from the ambient
delay(1); // minimum delay necessary to read values
ambientIR = analogRead(IRpin); // storing IR coming from the ambient
digitalWrite(IRemitter,HIGH); // turning the IR LEDs on to read the IR coming from the obstacle
delay(1); // minimum delay necessary to read values
obstacleIR = analogRead(IRpin); // storing IR coming from the obstacle
value[x] = ambientIR-obstacleIR; // calculating changes in IR values and storing it for future average
}
for(int x=0;x<times;x++){ // calculating the average based on the "accuracy"
distance+=value[x];
}
return(distance/times); // return the final value
}
//-- Function to sound a buzzer for audible measurements --//
void buzzer(){
if (distance>1){
if(distance>100){ // continuous sound if the obstacle is too close
digitalWrite(11,HIGH);
}
else{ // beeps faster when an obstacle approaches
digitalWrite(11,HIGH);
delay(150-distance); // adjust this value for your convenience
digitalWrite(11,LOW);
delay(150-distance); // adjust this value for your convenience
}
}
else{ // off if there is no obstacle
digitalWrite(11,LOW);
}
}
Of course you can edit it to fit in your own project. You can for example make a robot change direction or velocity based on the distance read from the IR sensor.
I also added an buzzer to this project if you wanna "hear" the distance.
// Simple Proximity Sensor using Infrared
// Description: Measure the distance to an obstacle using infrared light emitted by IR LED and
// read the value with a IR photodiode. The accuracy is not perfect, but works great
// with minor projects.
// Author: Ricardo Ouvina
// Date: 01/10/2012
// Version: 1.0
int IRpin = A0; // IR photodiode on analog pin A0
int IRemitter = 2; // IR emitter LED on digital pin 2
int ambientIR; // variable to store the IR coming from the ambient
int obstacleIR; // variable to store the IR coming from the object
int value[10]; // variable to store the IR values
int distance; // variable that will tell if there is an obstacle or not
void setup(){
Serial.begin(9600); // initializing Serial monitor
pinMode(IRemitter,OUTPUT); // IR emitter LED on digital pin 2
digitalWrite(IRemitter,LOW);// setup IR LED as off
pinMode(11,OUTPUT); // buzzer in digital pin 11
}
void loop(){
distance = readIR(5); // calling the function that will read the distance and passing the "accuracy" to it
Serial.println(distance); // writing the read value on Serial monitor
// buzzer(); // uncomment to activate the buzzer function
}
int readIR(int times){
for(int x=0;x<times;x++){
digitalWrite(IRemitter,LOW); // turning the IR LEDs off to read the IR coming from the ambient
delay(1); // minimum delay necessary to read values
ambientIR = analogRead(IRpin); // storing IR coming from the ambient
digitalWrite(IRemitter,HIGH); // turning the IR LEDs on to read the IR coming from the obstacle
delay(1); // minimum delay necessary to read values
obstacleIR = analogRead(IRpin); // storing IR coming from the obstacle
value[x] = ambientIR-obstacleIR; // calculating changes in IR values and storing it for future average
}
for(int x=0;x<times;x++){ // calculating the average based on the "accuracy"
}
return(distance/times); // return the final value
}
//-- Function to sound a buzzer for audible measurements --//
void buzzer(){
if (distance>1){
if(distance>100){ // continuous sound if the obstacle is too close
digitalWrite(11,HIGH);
}
else{ // beeps faster when an obstacle approaches
digitalWrite(11,HIGH);
delay(150-distance); // adjust this value for your convenience
digitalWrite(11,LOW);
delay(150-distance); // adjust this value for your convenience
}
}
else{ // off if there is no obstacle
digitalWrite(11,LOW);
}
}
Of course you can edit it to fit in your own project. You can for example make a robot change direction or velocity based on the distance read from the IR sensor.
Step 4: Connect it up.
Connect the resistor from the 5V pin to the anode pin of the IR LED receiver. All the anodes pins of the IR LEDs emitters to the digital pin 2. A wire goes from the analog pin 0 to the anode pin of IR LED receiver. Don't forget to connect all the cathode pins of the LEDs to the ground pin.
The buzzer is optional, but if you are using it connect to the digital pin 11 and the ground.
Infrared light isn't visible to naked eye, but you can see it thru a digital camera, it helps to see if the LED is working or not.
Take a look at the pics.
The buzzer is optional, but if you are using it connect to the digital pin 11 and the ground.
Infrared light isn't visible to naked eye, but you can see it thru a digital camera, it helps to see if the LED is working or not.
Take a look at the pics.
Step 5: It's done!
The sensor responds to 10 inches (25cm) or closer, so it's good for small distances.
Feel free to modify this project to your way, and tell me your progress. Comments are welcome.
Here is a video I've made.
Feel free to modify this project to your way, and tell me your progress. Comments are welcome.
Here is a video I've made.
Visit Our Store »
Go Pro Today »
please somebody help me.
I have done everything as shown but it does not work. I did not connect buzzer (I do not need it). I opened Serial monitor and got something like this: "?&7!" and then nothing.
I the type of LEDs matters (I do not what type I have- ordered from ebay).
Any advise?
Thank you.
will u teach me how to count the rpm using IR sensors.
if(distance>threshold){ //It's greater-than because the "distance" value gets higher when the object is closer
digitalWrite(LEDpin, HIGH);
} else {
digitalWrite(LEDpin, LOW);
}
I hope it helps!
There is no type of diode that can be safely and reliably connected in parallel this way. LEDs are not resistive light bulbs. The forward voltage Vf from device to device is not guaranteed to be the same for a given current. You are effectively limiting the current to the diodes (and not evenly) by maxing out the driver in the microcontroller.
In the simplest and least desirable solution you need one limiting resistor per diode, where the resistor size is (5 -Vf)/If where If is the desired forward current of the diode. So a typical steady 20mA and Vf of 1.3V is a resistor value of 185 ohms.
In practice you should reduce resistive losses by stacking 2 or three diodes such that (5 - 3*Vf)/If = 55 ohms and now you get three times the light for the same current output.
Further, considering the limitations of your power supply, the current can be pulsed much higher, and the values read back during the on cycle, so long as the average power dissipation stays below rated. In this case you will have to offload the switching with an external transistor.
Thanks you!
Abraço.
1 - The 100K resistor can be changed, higher the resistance, higher the sensibility of the sensor.
2 - All the IR LEDs should have a resistor before them, i'm not an expert on electronics. I put a 220 ohm resistor before all of them and the power consumption went as much as 10 times lower, I "THINK" (as i said before, I'm not a electronic guy, I'm a programmer guy), it may be something about the LED impedance (just a guess).
I've done a class to control the sensor, if anybody would like, i can send it. I'll be uploading project in a while, just after my beta testing!
https://www.sparkfun.com/products/9349
int readIR(int times)
{
for(int x=0;x {
digitalWrite(IRemitter,LOW);
delay(1);
ambientIR = analogRead(IRpin);
digitalWrite(IRemitter,HIGH);
delay(1);
obstacleIR = analogRead(IRpin);
distance += (ambientIR-obstacleIR);
}
return(distance/times);
}
There is no need to use an array to supply the average reading unless the individual values that contribute to the final average are also needed for something.