Proximity Sensor

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IR obstacle sensor - is something in front of me? 

This sensor's only job is to tell if something is in front of it or not. It is easy to wire to the Arduino. See the picture to the right to see how to wire it. 

The clear LED is an IR lightbulb. The dark bulb is a IR phototransistor. Phototransitors are devices that amplify current more when more light shines on it. The sensor works by emitting light in front of it and then the detector measures the amount of light reflection. The little screw on the board is a variable resistor that you can use to set the detection threshold. If the detector receives enough light, it outputs that something is there! 

 Plug the sensor into the Arduino, like the picture above. Then point a digital camera, like your cell phone or webcam, at it and see if you can see the light using the camera.
Note, only some cameras can see the light! 

The lightbulb not emitting visible light. It is only emitting a specific wavelength of infrared light (IR)! That means it is not visible to your eye.

Look at this picture and video for how this sensor works. 

The code!

This sensor gives outputs of either 0 or 1 for if something is close to it or not. This code below will print on or off readings to the Serial Plotter depending on if something is close to it or not. 
Step 1: Type out the code below in Arduino IDE

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Checking your code. 

Step 2: Push the check box at the top left of the page. This verifies (aka checks) if the code should work.
It "compiles" the code. That means it turns it from human readable to computer readable language.

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See if you get an error message?

Step 3: Check to see if an orange error message appears in the box at the bottom of the page. Try and fix it. If you cannot figure it out, ask your teacher for help. 

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Sending the code to the Arduino

Step 4. Upload your code to the board 
     a) Plug the USB cord to the Arduino and computer. 

     b) Select the right arrow button (next to the check mark) to send your code to the board. 

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Did you get an error? (Is it working right?) 

You may get a "Problem uploading to board" or something similar.
If you do, it is because your Arduino does not know where the Arduino is plugged in. Or, your USB cord may not be plugged all the way in. 
Follow the steps in the picture below if you get the Port Error. 
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          Open the tools tab, Port, and select the port COM that says Arduino. 

Step 4) If you fixed the port, push the arrow button at the top again.
Give the board a second to upload, it should be blinking quickly and then run your code.

​Let your teacher know if it still does not work and you need help. ​

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Serial Monitor: Seeing what Arduino is saying :) 

The Serial Monitor is where you can see text or data that the Arduino is outputting. After you upload your code to the board successfully, select the magnifying glass on the top right of the IDE. 

After you click that button, a separate window will open up after a few seconds. 
​It will also restart your Arduino. After a few seconds, you will start seeing your proximity sensor data appear. A new line will appear every 1/5th of a second code's delay value was 200 ms or .2 sec.  
The data will read on or off if you are close vs far from the senor. See the example below.

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Buzz and Light up when Close

There is not that much you need to add to this code to get the onboard LED to light up when something sets off the proximity sensor. All I did was add to the if else statement High/Low digital writes and declaring the builtin LED's pin mode in setup. 

Once you get this to work, you can wire up whatever you want to pin 13 to set it off when the sensor is triggered. Maybe add a buzzer so you hear when something is close?