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ArduSensor Phototransistor Quickstart Guide



The Basics:

 

A phototransistor can be used as a black-to-white (line) detector or a distance finder (.5 to 1cm away).  They are also ideal for coin slots (fast motion across the sensor).  They are made up of two main components: a IR LED, and a IR Receiver.  The phototransistor sends an infrared pulse through the IR LED, and then when the IR Receiver picks up that same pulse that had bounced off an object, it sends a reading of how far away the object is.

 

Assembly:

 

First off, if you don’t know how to solder, go here to learn the basics so that you are thoroughly prepared to assemble your kit.

 

Parts in Kit:

 

Qtechknow ArduSensor Phototrasnsistor PCB (Printed Circuit Board)

QRD1114 Phototransistor

4.7K Ohm Resistor - 1/4W

200 Ohm Resistor - 1/4W

Male Headers (5)

 

Tools Needed to Assemble:

 

Soldering Iron

Rosin Core Solder

Safety Glasses

Safety Mask

Vice or Third Hand

 

You will need to get on your own:

 

Arduino Leonardo with micro-B USB Cable

or

Arduino Uno with USB-B Cable

 

When using lead, take precautions like:

 

  • Make sure to wash your hands with soap and water twice after you solder
  • Don’t eat the solder
  • Don’t touch your face or eyes after touching the solder
  • Wear a mask to prevent the solder smoke to come into your mouth, and inhale it
  • When working with hot solder, you especially want to wear eye protection, to protect your eyes

 

Assembling the Kit:

 

Take out the ArduSensor Phototransistor PCB out of the the bag and put face up into a vice or third hand.

Insert the phototransistor into the copper holes corresponding.  Make sure that the writing (QRE1114) is facing to the right when you are looking at the “ArduSensor” text.

 

Flip the PCB over and put it back into the vice or third hand face down, so that all of the leads show on the back and bend the leads outwards towards the outline of the PCB.

Put your soldering iron on one of the junctions where there is a copper hole, and one of the phototransistor legs popping through it.

Wait three seconds, and then take your solder, touch it briefly to the junction, and then take your soldering iron away.  The junction should look something like the 'OK' volcano shapes:

Credit: Adafruit

Repeat this process 3 more times to the other joints with the copper hole and a phototransistor leg popping through it.

Trim the leads with your diagonal cutters, so that they don’t poke you

After you are done, flip the PCB over again so that the text and phototransistor are facing upwards.

Take your 4.7K (Yellow, Violet, Red) ohm resistor out.

Bend the leads so that they make an upside-down “U” shape.  

Put these two leads into the 4.7K ohm resistor footprint on the PCB.  

Flip the PCB over and bend the leads of the resistor out in opposite directions.

Solder the two copper holes that have resistor legs popping out of them (using the same method as before).

 

Trim the leads so that they don't poke you.

Take your 200 (Red, Black, Brown, Gold) ohm resistor out.

Bend the leads so that they make an upside-down “U” shape. 

Put these two leads into the 200 ohm resistor footprint on the PCB, flip the PCB over, and bend the leads of the resistor out in opposite directions.

Solder the two copper holes that have resistor legs popping out of them (using the same method as before).

Trim the leads so that they don't poke you.

Take the 1 pin male header and 4 pin male header, and put them into these Arduino pins:  The 1 pin male header goes into A0, and the 4 pin male header goes into VIN, GND, GND, and +5V as shown below in the picture.  

Place the ArduSensor Phototransistor on top of these pins, making sure that the 1 pin male header goes into the 1 pin male header socket, and the 4 pin male header goes into the 4 pin male header.

Solder in place.  But make sure that you don’t put too much solder in, because that can cause the ArduSensor Phototransistor to be permanently installed on your Arduino!

Wait for the ArduSensor Phototransistor to cool off (around 20-30 seconds), then pull out of the Arduino sockets.  Now you are finished soldering your ArduSensor Phototransistor!

 

Programming:

 

If you haven’t downloaded the Arduino IDE, go here to download the latest version.  If you haven’t installed drivers for the Arduino (haven’t downloaded the software yet, or haven’t done this step yet), read the following table:

 

 

If you have...

Arduino Uno

Arduino Leonardo

Mac:

No drivers needed, proceed to the next step

Go here, then proceed

Windows:

Go here, then proceed

Go here, then proceed

 

 

Put in your ArduSensor Phototransistor to your Arduino like this: Put the 1 pin male header into A0, and the 4 pin male header in VIN, GND, GND, and +5V.  

Plug in your Arduino with your USB cable (USB-B on the Arduino UNO or earlier, and USB-microB for Arduino Leonardo) to your computer.  Download this zip file and unzip onto your computer.  If you are on a Mac, double click the folder labeled “FishBank-ArduSensor-Phototransistor-Example-Code-f78ead3”, double-click the file named “PhototransistorRead.ino”, then press OK when the dialogue box pops up. If you are on a Windows computer, press Save instead of Open when you press the download button, double click the folder labeled “FishBank-ArduSensor-Phototransistor-Example-Code-f78ead3”, double-click the file named “PhototransistorRead.ino,” and then press OK in the pop up box.

The Arduino IDE should open up with the ArduSensor Phototransistor Read sketch.  This sketch prints out the reading of the phototransistor on the serial monitor.

First, make sure to select the board that you are using from Tools > Board.

Then, go into Tools > Serial Port, and select the correct COM/Serial Port.  On a Mac, the usual Serial Port will be /dev/tty.usbmodemfa131.  Any small variation of that will be fine.

On Windows, the COM Port will usually be COM 4, and anything lower or higher might work.

Here are the basic buttons/functions in the Arduino IDE:

Now let’s upload the sketch/code to the Arduino.  Plug one end of the cable into your Arduino, and then the other end into your computer.  Press the Compile + Upload button (Verify if there is any errors in the code, and then upload the sketch/code onto the Arduino), and the program will run on the Arduino.

Press the Serial Monitor button (in the upper-right hand corner), and you should see that it prints out a number from 0 to 100.

When you put your hand closer to the phototransistor, it reads a higher value, and when your hand is farther away from the phototransistor, it reads a lower value.

If you have any more questions on this product, contact Qtechknow Tech Support at support@qtechknow.com

 



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